Impact case study database
- Submitting institution
- University of Sussex
- Unit of assessment
- 10 - Mathematical Sciences
- Summary impact type
- Environmental
- Is this case study continued from a case study submitted in 2014?
- No
1. Summary of the impact
Insights from mathematical models developed at Sussex have been implemented in Ukraine (the world’s largest producer of sunflower seeds and in the top six producers of potatoes, wheat, barley and corn globally) with the following impact:
Improvement of farming practices in the Prydniprovsky region of Ukraine, resulting in increased crop viability by 7-12% and reduction in pest control costs by 15-20%. The region contains almost 20% of the total Ukrainian sown area of agricultural crops and occupies a third of the country’s steppe.
Development by Ukrainian biotech companies of natural biostimulants which have been used throughout Ukraine, increasing yields of wheat (by 11-21%), barley (9-18%) and sunflowers (19-63%), tomatoes (20-66%), potatoes (10-12%) and cucumbers (23-26%). These biostimulants reduce the need for environmentally harmful pesticides, and are proving to be a successful alternative for use in organic farming.
2. Underpinning research
With the rapidly growing world population and major changes in the global climate, an important factor in sustaining food productivity and security is the ability to effectively and environmentally-safely protect agricultural crops. Their performance can be hindered by many factors, including significant risk from pathogens and parasites that annually cause losses estimated to be in the order of hundreds of billions of dollars. For many years, this problem was addressed using chemical pesticides, but the emergence of pathogen resistance and the potential harm to humans have necessitated the development of alternative approaches.
Having previously published several highly-cited papers on mathematical modelling of the effects of awareness on control of directly transmitted infections, in 2017, Blyuss collaborated with colleagues from Visva-Bharati University in India on modelling vector-borne infections of crop plants and their control [R1]. Their paper proposed a mathematical model for control of mosaic disease through application of nutrients (fertilisers) and insecticides. Analysis of the conditions for disease persistence produced quantitative results for the amounts of nutrients and insecticides that need to be used in order to achieve disease eradication, depending on various factors, such as the rate of disease transmission from vectors to plants, vector mortality, as well as the carrying capacity of crop plantations, and farmer awareness based on observing the proportion of infected plants.
Subsequently, in collaboration with colleagues from India and Ukraine, Blyuss conducted another study that mathematically modelled the effects of applying microbial biostimulants for the purpose of improving crop performance and protecting crops against parasites [R2]. That work identified quantitative relations between the amount of biostimulants required for disease eradication and various features of disease transmission, as well as parameters characterising the performance of these biostimulants, such as their effect on inducing reduction in disease transmission from vectors to plants, and the increase in vector mortality. Although these models used an example of plant mosaic disease, the modelling framework and results are applicable to other plant pests and parasites.
One very promising approach for safe and effective control of crop parasites currently pursued by some of the world's largest agrochemical companies is that of RNA interference (RNAi), also known as “gene silencing”. RNAi is a fundamental biological process (discovery of this was recognized with a Nobel Prize in 2006), by which eukaryotic cells can control expression of specific genes after they are already transcribed. In the specific context of protecting plants from infection, RNAi is used in two different ways. Providing plants, by means of spraying or root soaking, with appropriate double-stranded RNA (dsRNA) can help them stop expressing genes that are necessary for a successful infection. On the other hand, RNAi can also be used to target parasites, where parasites feed on plants and ingest dsRNA that then triggers the process of RNAi against parasites’ own genes, thus reducing their fecundity and causing mortality.
The progress in developing RNAi-based tools for pest control, particularly microbial bioregulators, has been hampered by the lack of detailed quantitative description of the dynamics of RNAi in plants and parasites. To address this problem, Blyuss, Kyrychko and Neofytou at Sussex developed the first ever mathematical models of RNAi in plants [R3-R5] that provided quantitative insights into the mechanisms of how plants respond to infections by means of RNAi. These models showed how the optimal rate at which plant cells are able to express necessary dsRNA constructs, protecting them from infection and/or parasitism, depends on other fundamental parameters, such as plant cell maturation rate, the rate of spread of infection within the plant, as well as how RNAi in the cells of parasites can be amplified by using other types of small interfering RNAs (siRNAs). These results have provided quantitative predictions of the influence of different parameters on the effectiveness of RNAi in silencing plant genes involved in infestation, as well as the essential nematode genes.
Subsequently, Blyuss established contacts with colleagues at three research institutes of the National Academy of Sciences of Ukraine, and together they have used theoretical findings from these models to develop natural microbial biostimulants produced from soil bacteria that are capable of protecting crops against parasitic nematodes using the mechanism of RNAi. The results of this research have been published in Frontiers in Plant Science [R6], the world’s most cited peer-reviewed journal in the field of plant science, where it was experimentally shown how natural microbial biostimulants are able to reduce the levels of nematode infestation in wheat, while targeting essential nematode genes. By January 2021, this paper was viewed over 8100 times by readers from 38 countries and all continents. It has also attracted significant attention on Twitter and in the press.
3. References to the research
R1. F. Al Basir, K.B. Blyuss, S. Ray, Modelling the effects of awareness-based interventions to control the mosaic disease of Jatropha curcas, 2018, Ecological Complexity, vol. 36, pp. 92-100. doi: 10.1016/j.ecocom.2018.07.004
R2. K.B. Blyuss, F. Al Basir, V.A. Tsygankova, L.O. Biliavska, G.O. Iutynska, S.N. Kyrychko, S.V. Dziuba, O.I. Tsyliuryk, O.O. Izhboldin, Control of mosaic disease using microbial biostimulants: insights from mathematical modelling, 2020, Ricerche di Matematica, vol. 69, pp. 437-455. doi: 10.1007/s11587-020-00508-6
R3. G. Neofytou, Y.N. Kyrychko, K.B. Blyuss, Mathematical model of plant-virus interactions mediated by RNA interference, 2016, Journal of Theoretical Biology, vol. 403, pp. 129-142. doi: 10.1016/j.jtbi.2016.05.018
R4. G. Neofytou, Y.N. Kyrychko, K.B. Blyuss, Time-delayed model of immune response in plants, 2016, Journal of Theoretical Biology, vol. 389, pp. 28-39. doi: 10.1016/j.jtbi.2015.10.020
R5. G. Neofytou, Y.N. Kyrychko, K.B. Blyuss, Time-delayed model of RNA interference, 2017, Ecological Complexity, vol. 30, pp. 11-25. doi: 10.1016/j.ecocom.2016.12.003
R6. K.B. Blyuss, F. Fatehi, V.A. Tsygankova, L.O. Biliavska, G.O. Iutynska, A.I. Yemets, Y.B. Blume, RNAi-based biocontrol of wheat nematodes using natural poly-component biostimulants, 2019, Frontiers in Plant Science, vol. 10, 483. doi: 10.3389/fpls.2019.00483
4. Details of the impact
This Impact Case Study focuses on Ukraine, which, according to the latest data from the UN Food and Agriculture Organisation (Statistics Division), is the world’s largest producer of sunflower seeds, and in the top six producers of potatoes, wheat, barley and corn globally. In spring 2019, Ukraine overtook China to become the third largest exporter of agricultural products to the EU after Brazil and the USA. Translation of research results [R1-6] has resulted in a better-informed practices around using fertilisers and pesticides to protect crops against pests, and in the development of natural, environmentally-safe crop biostimulants. This has led to the increase in crop yields by 7-12% with an associated reduction in expenses for crop protection of 15-20% in the Prydniprovsky region of Ukraine, which contains 20% of the total Ukrainian sown area and produces 8% of the world’s sunflower. Natural microbial biostimulants developed through translation of theoretical results have already proved effective in increasing crop yields in major cereals, such as wheat, barley and sunflowers by 11-21%, 9-18% and 19-63%, respectively, while for vegetables, the yields for tomatoes, potatoes and cucumbers have increased across the country by 20-66%, 10-12%, and 23-26%.
Changing farming practices to improve crop viability and reduce pest control costs
In 2017, Blyuss visited Ukraine and signed a Memorandum of Understanding between the University of Sussex and the Prydniprovsky Scientific Centre of the National Academy of Sciences of Ukraine (PSC). In collaboration with colleagues from the Dnipro State Agrarian and Economic University and the PSC, during 2017-2018 Blyuss translated theoretical results from R1-3 into practical recommendations for farmers on optimal strategies of using nutrients, pesticides and microbial biostimulants for protecting crops against pests, based on monitoring the levels of infection at crop plantations. These practical recommendations, focused on crop pests native to the steppe region, were subsequently distributed to farming companies and agribusinesses in the Prydniprovsky region of Ukraine, with 40% of farmers in the region adopting these recommendations into their farming practices. In terms of reach, the Prydniprovsky region contains almost 20% of the total Ukrainian sown area of agricultural crops and occupies a third of the country’s steppe. It has an abundance of fertile chernozem soil, and, according to latest data from the Ukrainian National Statistics Service, produces 20.2% of the total Ukrainian harvest of wheat, 21.8% of barley, 13.3% of vegetables, and 26.3% of sunflower [S1, link 3]. In fact, in 2019 that region alone produced 8% of the total amount of sunflower produced worldwide.
Professor Anatolii Bulat, President of the Prydniprovsky Scientific Centre, has noted:
“Currently, monitoring and control of the processes of growth and development of agricultural crops on farming lands of various agribusinesses in the Prydniprovsky region are performed in accordance with the results of scientific research and technical recommendations developed by Dr K.B. Blyuss…. Through close collaboration with farmers and agribusinesses, … currently around 40% of farmers in Prydniprovsky region are already using above-mentioned technical recommendations. This has allowed farmers and agribusinesses to increase the survivability of crops by 7-12%, to improve quality and yields of cereal crops, and to reduce expenses associated with control of crop pests by 15-20%, compared to 2015-2017 when these techniques were not used. Reductions in expenses were associated with reduced fuel and personnel costs, as well as a substantial reduction in the amount of nutrients, fertiliser and pesticides being used. The latter factor is a particularly important achievement of the newly developed technical recommendations from the perspective of reduction and minimisation of the negative impact of pesticides on environment and biodiversity.” [S1].
With 18% of the working population of Ukraine being involved in agriculture, new technical recommendations on monitoring of crop infestation and the use of pesticides have had a direct impact on performance of local agribusiness in the Prydniprovsky region.
Mr N. Nodzrin, Chief Agronomist of the company “Pisarevsky Oleksandr Stepanovych” based in Vodyane, has said: “As a result of applying practical recommendations regarding monitoring the levels of crop infestation with pests, as well as optimal use of fertilizers and biostimulants, that have been developed by Dr K.B. Blyuss together with colleagues, our expenses associated with control of crop pests have reduced by 12.5-18.0%, while the viability of wheat and barley plants has increased by 7.5-10%.” [S2].
Similarly, Mr Viktor Lisnyi, the Director of “Lisnyi Viktor Mykolayovych” company, specializing in producing cereal grains, sunflower and corn on its 11ha farm in Promin’, has noted:
“This year we have used a new approach to monitoring of plant growth and protection against pests using pesticides and fertilizers, developed by Dr K.B. Blyuss together with colleagues ... This has allowed us to not only increase the viability of wheat, barley, oat and rapeseed plants by 8-10% on average, but it has also reduced our costs for control of pests of these plants by 15-18%.” [S3].
Enabling the development of successful organic biostimulant products for improved crop protection and yields
In R3-5, Blyuss and Kyrychko proposed and analysed mathematical models of RNA interference, explaining quantitatively how this process develops in plants, and how it can be used to target plant parasites. Results of these models helped their colleagues in the Institute of Microbiology and Virology of the National Academy of Sciences of Ukraine select metabolites of soil bacteria that result in the highest levels of within-plant production of siRNAs protecting plants against parasites, and it was these metabolites that formed the basis of natural microbial biostimulants. After testing in laboratory, greenhouse and field conditions, in 2018 Ukrainian agro-investment and agrochemical companies “Bioinvest-agro” ( http://www.bioinvest.com.ua) and “Imptorgservice” ( imptorgservis.uaprom.net) produced these biostimulants and sold them to farmers and over 100 major agribusinesses around Ukraine and in Kazakhstan. The latter of these companies has annual sales of $500,000 - $1million. Besides direct economic impact in terms of profits to these agrochemical companies, the biostimulants have also resulted in a substantial improvement of crop performance for individual farmers and agribusinesses using them. More specifically, across different regions of Ukraine, these biostimulants have increased yields of winter wheat, barley and sunflowers by 11-21%, 9-18% and 19-63%, respectively, while for vegetables, the yields for tomatoes, potatoes and cucumbers have increased across the country by 20-66%, 10-12%, and 23-26% due to using natural biostimulants [S4, S5].
By virtue of being produced from natural products of soil bacteria, natural microbial biostimulants can be used for organic farming. This is extremely important, since organic farmers suffer substantial losses due to inability to protect their crops against pests using conventional pesticides. In this respect, these natural microbial biostimulants are providing a viable alternative, which allows to protect crops against parasites, while minimizing negative effects on the environment, and maintaining standards of organic farming. One of these biostimulants – “Phytovit”, produced by “Bioinvest-agro” [see R6] – has been approved for organic farming and even received international “Organic standard” certification recognized by the EU and Switzerland [S4] and is currently used by some of the largest organic farming companies in Ukraine.
Results of theoretical and experimental work on natural biostimulants have been published in a joint research publication [R6] in Frontiers in Plant Science, the world’s most cited journal in the field of plant science. Due to major significance of this work in terms of providing effective, and at the same time, environmentally safe, tools of pest control, this work has been covered by a large number of global media specializing in farming and agriculture. This includes articles in English, French, Italian, Spanish, Portuguese, Russian, and Turkish [S6].
The significance of this work has been recognised by an award to Blyuss and Kyrychko of Letters of Gratitude from the PSC, which is the highest honour that can be awarded (only once) to any scientist for their major scientific contribution to solving problems of significant practical importance. These awards were given to Blyuss and Kyrychko on the 17 May 2019 at the annual Day of Science ceremony, organised by the National Academy of Sciences of Ukraine [S7].
Natural microbial biostimulants are already widely used in Ukraine and Kazakhstan. The next phase of impact will concentrate on certification of other natural microbial biostimulants for the purpose of their use in organic farming. The largest Ukrainian producer of organic commodities, which is also the second largest organic grower in Europe and the biggest exporter of organic soybean and corn from Ukraine to the EU, is currently testing these biostimulants for the purpose of adopting them as main tools of pest control in its agricultural lands.
5. Sources to corroborate the impact
S1. A scanned copy of the signed and stamped letter from the Prydniprovsky Scientific Centre of the National Academy of Sciences of Ukraine, confirming the adoption of technical recommendations, as developed by Dr Blyuss, by farmers in Prydniprovsky region (clearly stating the level of uptake, and reach of impact), together with quantitative data on the improved crop performance. Also, National Statistics Service of Ukraine (summary of agricultural production) :
S2. Signed and stamped letter from “Pisarevsky Oleksandr Stepanovych”, an agribusiness in Prydniprovsky region, confirming the use of technical recommendation developed by Dr Blyuss, as well as data on their benefits on this particular farm.
S3. Signed and stamped letter from “Lisnyi Viktor Mykolayovych”, an agribusiness in Prydniprovsky region, confirming the use of technical recommendation developed by Dr Blyuss, as well as data on their benefits on this particular farm, as well as data on their benefits on this particular farm.
S4. Signed and stamped letter from “Bioinvest-agro”, a biotech company in Ukraine producing and selling microbial biostimulants, confirming company’s own economic benefits in terms of profits, as well as an impact for farmers in terms of improved productivity and reduced crop losses due to pests. Also, see organicstandard.ua list of 2020 Organic Standard Certified Products for “Phytovit” organic certification (no. 2.3.2.48 on p. 97)
S5. Signed and stamped letter from “Imptorgservice”, a Ukrainian agrochemical company, producing and selling microbial biostimulants confirming company’s own economic benefits in terms of profits, as well as an impact for farmers in terms of improved productivity and reduced crop losses due to pests.
S6. A PDF with a selection of media stories covering this work.
S7. The Letters of Gratitude from the Prydniprovsky Scientific Centre of the National Academy of Sciences of Ukraine (NASU). Information about the Day of Science ceremony on the official governmental website of the NASU, which specifically mentions Dr Blyuss’ and Dr Kyrychko’s awards can be found here (PDF archive of webpage and translation are supplied, as webpage is currently being moved to a new server): http://www1.nas.gov.ua/rsc/psc/chronicle/Pages/nov_22_05_19.aspx
- Submitting institution
- University of Sussex
- Unit of assessment
- 10 - Mathematical Sciences
- Summary impact type
- Technological
- Is this case study continued from a case study submitted in 2014?
- No
1. Summary of the impact
Mathematics research at Sussex has significantly improved the operations of Ambiental, a UK company that provides computational flood risk assessments. Specifically, the results have halved the amount of time the company needs to produce an assessment for clients. This doubling of productivity has enabled Ambiental to launch new products and expand its market share, now reaching 50% of the UK flood insurance market. It has also grown its business overseas, with new customers in [text removed for publication]. [Text removed for publication].
2. Underpinning research
The research project was prompted by a conversation between Lakkis and Ambiental [text removed for publication] in 2013. Ambiental supplies flood maps, data sets, catastrophe models, flood forecasting products and environmental reports to clients including insurers, reinsurers, brokers, governments internationally as well as non-government organisations, commercial clients and strategic partners. However, the company was facing instabilities in [text removed for publication].
Lakkis’s research focused on developing an extension of the shallow water equations to model rivers and floods with precipitation, recharge and infiltration, while also deriving a stable computer method to be used in Ambiental's code. The shallow water equations, also known as Saint-Venant’s equations, use fundamental physical conservation laws, such as the conservation of mass, momentum and energy, to simulate and predict how fluids move over the Earth's surface. Discretised, i.e. converted into computer code, these equations form the core of software used to simulate floods and assess their risk in a given area of the world. Kinetic schemes are one way of discretising shallow water equations.
Unless conducted carefully by respecting mathematical and physical principles, the discretisation of shallow water equations can easily be unstable in so-called shock scenarios, e.g. large amounts of extra water added to a system, say from heavy rainfall or a sudden burst. The numerical instability of code means the equations as such produce [text removed for publication] that only postprocessing by highly skilled practitioners can understand and discard, leading to time and labour consumption.
The research by Lakkis and his team solved this fundamental problem. The stability of simulations is of paramount importance when running Monte Carlo methods to model stochastic shallow water equations, when the rainfall is given as a random term [3.3]. This is crucial to estimating statistical variables in the form of flood maps that are then used to package products for Ambiental's customers. Since unstable runs require human intervention and thus associated costs and times, Ambiental would benefit from reduced costs and delivery times if able to eliminate these instabilities from its code [5.1].
To improve Ambiental's code, Lakkis discretised the shallow water equations by applying a delicate computational technique called [text removed for publication] by using kinetic schemes. Kinetic schemes derive from a concept called kinetic equations where the water flow is viewed as the average of huge numbers of microscopic particles, and this allows the model to account for other features of the flow, such as friction caused by contact between particles and walls and when the added water mixes.
When the microscopic kinetic equations are averaged, the original (macroscopic) shallow water equations are recovered. Discretising the kinetic equations, which are linear, is easier but the code would be much more expensive to run; by averaging such discretisation, an efficient code is obtained that has built-in up-winding. This allows computer code to solve the equations accurately and in a stable manner. Details are found in [3.1], where Lakkis et al. justify the addition of rainfall and ground infiltration in such discretisation. [Text removed for publication], a one-dimensional open source proof-of-concept code is available at [3.2].
Tests showed that using the model gave very similar results to data from a real-world flume experiment [3.1].
3. References to the research
[3.1] M. Ersoy O. Lakkis P. Townsend (2021) A Saint-Venant Model for Overland Flows with Precipitation and Recharge Mathematical and Computational Applications 26 no. 1 pp. 1-27. Published 29 December 2020: https://www.mdpi.com/2297-8747/26/1/1
[3.2] M. Besson O. Lakkis P. Townsend (2013) Finite volume code 1D Saint Venant https://sourceforge.net/projects/finitevolumecode1dsaintvenant/
[3.3] P. Townsend O. Lakkis (2018) A Multilevel Approach to Simulation of a Stochastic Shallow-Water with Rainfall System AGU Fall Meeting Abstracts, 2018AGUFMNG21A0802T http://adsabs.harvard.edu/abs/2018AGUFMNG21A0802T
Research funding
[3.4] O. Lakkis and P. Townsend (2013 – 2017) EPSRC CASE award with Ambiental Technical Solutions Ltd. “Computational stochastic shallow water equations for flood risk assessment” £76,276 (from EPSRC) + £22,883 (from Ambiental)
[3.5] M. Dashti, O.Lakkis, C. Makridakis, V. Styles (2015 – 2020) EU Marie Sklodowska-Curie International Training Network “Mod Comp Shock - Modelling and Computing Shocks and Interfaces” £600,872
[3.6] O. Lakkis and M. Besson (2013) Erasmus support for intern M. Besson and HEIF “Computational flood risk assessment” £6,200
4. Details of the impact
The work under Lakkis's leadership featured in this case study – though inspired by initial discussions with Ambiental's staff – was carried out independently of Ambiental and without sight of the problematic [text removed for publication] code. Nevertheless, it was natural that, once Lakkis produced and openly circulated his findings, they would be relevant and potentially very useful for the company, which proved to be the case. To maximise the impact, an intern student, working under Lakkis, was tasked with integrating those components identified and derived from the existing research [3.2] into the specific [text removed for publication] commercial code. A PhD student of Lakkis, working part-time for Ambiental, further improved the code and worked with Lakkis on the mathematical justification of these improvements.
Lakkis identified a problem with the way the shallow water equations were implemented and then they ran on real-world scenarios such as periods of heavy rain or sudden addition of water (non-conservative regime). Lakkis's team saw that by modifying the underlying kinetic equations (a topic Ambiental's developers were unfamiliar with) to cover the non-conservative equations, there was a possibility of importing stable kinetic schemes (previously only tried for conservative regimes of shallow water) to model the non-conservative scenarios.
In 2014, Ambiental developers integrated the method established by Lakkis in the form of [text removed for publication] fluxes via kinetic averaging as described in section 5.6 of [3.1] within the company’s code. The main import of these novel fluxes is extra stability, and thus robustness, for each single simulation of a flow. Since these simulations could be run hundreds of thousands, or even millions, of times in Monte Carlo runs, this robustness is crucial to reduce, or even eliminate, human intervention in the form of postprocessing of runs and the development of multilevel Monte Carlo methods [3.3].
According to [text removed for publication], the results of the academic work “impacted the whole process”. Previously, filtering out the unstable mathematical simulations from the company’s flood predictions was a time-consuming manual task. It’s “actually the single longest process in building flood maps,” [text removed for publication] [5.1].
After integrating Lakkis’s findings into the [text removed for publication] code, the company [text removed for publication] the amount of time and resources needed to root out instabilities.
[Text removed for publication].
The work of Lakkis and his team has thus benefitted Ambiental’s commercial operations via computational and quantitative products, comprising:
The delivery of FloodMap products is significantly lower effort since 2013 – given the considerable reduction in required re-runs. "Bearing in mind that we run 100’s of thousands of simulations to create a national model – even a reduction of a small percentage of unstable simulations can have a significant uplift in efficiency". [5.1]
The developed FloodCat processes, which "are still in use today – and will help with future product builds". [5.3]
The impact and growth enabled Ambiental to expand its business; it now works with 50% of the UK insurance market, as well as administrations at various levels in [text removed for publication] [5.1].
[Text removed for publication].
As a commitment to further knowledge exchange and benefit from this collaboration, [text removed for publication], the lead software developer of [text removed for publication] at Ambiental since 2008, will join Lakkis’s research team in 2021 for an EPSRC-funded PhD in collaboration with Ambiental, to learn and specialise further numerical and computational techniques to flood-risk modelling.
- Submitting institution
- University of Sussex
- Unit of assessment
- 10 - Mathematical Sciences
- Summary impact type
- Societal
- Is this case study continued from a case study submitted in 2014?
- No
1. Summary of the impact
Research by the Mathematics Applied to Biology Group at Sussex has supported COVID-19 control measures at the levels of (1) national policy (in Ukraine) and (2) regional healthcare management in East and West Sussex, and Brighton & Hove (in the UK). Sussex research co-produced by academics and decision makers within the Ukrainian equivalent of the Scientific Advisory Group for Emergencies (SAGE) fed directly into public health policy interventions that have subsequently been implemented by Ukraine’s Cabinet and the National Security and Defence Council. As a result, the Ukrainian Government devolved implementation of control measures to regional administrations (June 2020) and moved to a tiered system and adaptive quarantine measures (July 2020). These measures enabled the Ukrainian government to make the best-informed policy decisions they could, which the government confirms were as effective as possible in slowing the spread of the pandemic. In parallel, research at Sussex has (a) underpinned decision making with respect to hospital and mortuary demand in East Sussex, West Sussex, and Brighton & Hove. This research has also helped Public Health Local Authorities to (b) translate UK-SAGE national guidelines to regional level for decision making, (c) prevent or mitigate miscalculations in ward and body storage planning, thereby avoiding monetary and resource mismanagement, and (d) provided key scientific evidence for Urgent Community Response’s (UCR) successful business case which secured £1.63 million for care services in West Sussex to deal with the additional burden brought about by COVID-19.
2. Underpinning research
The COVID-19 pandemic, which has already caused over 94 million cases and over 2 million deaths worldwide (at the time of writing), has led to an unprecedented mobilisation of scholarly efforts in order to shed light on the biology of the virus, its means of transmission and to support the development of scientific-evidence-based interventions and policies locally and nationally. The Mathematics Applied to Biology Group has a strong track record in developing and applying epidemiological models to real world problems [R1-3]. The need for designing robust and effective intervention measures has brought into focus the need for mathematical models that could provide important insights into disease dynamics and its subsequent spread, as well as a quantitative comparison of the effects of different intervention scenarios.
Mathematicians at Sussex, in particular Blyuss and Kyrychko , have a track record of developing models with non-Markovian incubation and recovery periods [R1-3] which is a natural feature of the virus’ biology. Although this is often overlooked for the sake of model simplicity, this is an essential feature of the disease. Building on this work, they developed a mathematical model for the spread of SARS-Cov-2 which featured the inclusion of realistic distributions of incubation and recovery periods, and population age structure in different regions [R1]. The latter feature accounts for the strong age effect in mortality rates due to COVID-19. This model was first parametrised using UK regional data, and its results demonstrated the major role of the region-specific age distribution of the population on the effectiveness of lockdowns. Whereas many papers analysed the effects of UK lockdown at national level or compared the effects of age distribution on the spread in different countries, as far as Sussex is aware, the work by Blyuss and Kyrychko was the first to demonstrate the significant impact of age distribution on local epidemic dynamics and the effectiveness of local lockdown [R1].
In collaboration with Dr Igor Brovchenko, chair of the Special Committee of the National Academy of Sciences of Ukraine on Mathematical modelling of dynamics and containment of COVID-19, and building on the research in [R3], Blyuss and Kyrychko developed a model for the spread of COVID-19 in Ukraine [R4]. This model was based on extensive clinical and epidemiological data collected by Ukraine’s Ministry of Health in April-May 2020, which provided accurate parameterisation of incubation, hospitalisation, recovery and death, as well as age-dependent characteristics of the disease. In [R4], they reproduced observed time course of disease, developed short-term forecasts of epidemic dynamics, and also considered the effects of different intervention scenarios on mitigating the effects of the disease. They found that on a longer timescale, a 30% reduction in contacts within the working population resulted in a more substantial reduction in total cases and deaths than a similar reduction in school contacts, or a 50% shielding of people over 60 years of age.
An important component of epidemic models is their integration of real-world data for the purpose of parameter estimation and forecasting. Madzvamuse has a wealth of expertise in Bayesian and other inference methods for more complex systems such as partial differential equations [R4]. Building on his links with experimental biologists, Madzvamuse and his team, including Van Yperen, were tasked with developing a model for forecasting hospital and mortuary demand in East Sussex, West Sussex, and Brighton & Hove. The team used local NHS datasets from the NHS Situational Reports and Office of National Statistics to generate a data-driven ordinary differential equation model with the necessary parameter inference component, which relied on previous approaches developed by Madzvamuse and colleagues [R5]. In particular, the research showed that one can recover estimates of parameters which reflect the impact of the epidemic locally and that, whilst some of these estimates are in line with nationally derived parameters, others are different [R5]. This in part confirmed the views of local authorities across Sussex that the burden on Sussex was significantly less compared to other regions, like Kent or Manchester. Madzvamuse and his team built an online prototype translational toolkit ( https://alpha.halogen-health.org) which provides a description of the model derived in [R5], its assumptions, its methodology, and its outputs, in a user-friendly format and language accessible to non-academics. This tool allows users to carry out scenario-based forecasting driven by the rigorous research in [R5], and provides an educational environment that gives users a hands-on experience of mathematical modelling.
3. References to the research
[R1] K.B. Blyuss, Y.N. Kyrychko. Effects of latency and age structure on the dynamics and containment of COVID-19, Published online April 2020, medRxiv. doi: 10.1101/2020.04.25.20079848. Subsequently in J. Theor. Biol., 2021; 513, 110587: DOI: 10.1016/j.jtbi.2021.110587.
[R2] N. Sherborne, K.B. Blyuss, I.Z. Kiss. Dynamics of multi-stage infections on networks. Bull. Math. Biol., 2015; 77: 1909-33. DOI: 10.1007/s11538-015-0109-1.
[R3] Y.N. Kyrychko, K.B. Blyuss, I. Brovchenko. Mathematical modelling of the dynamics and containment of COVID-19 in Ukraine. Sci. Rep., 2020; 10:1-11. DOI: 10.1038/s41598-020-76710-1.
[R4] E. Campillo-Funollet, C. Venkataraman, A. Madzvamuse. Bayesian Parameter Identification for Turing Systems on Stationary and Evolving Domains. Bull. Math. Biol., 2019; 81: 81–104. DOI: 10.1007/s11538-018-0518-z. Research supported by Leverhulme Trust Research Project Grant [G1]
[R5] E. Campillo-Funollet, J. Van Yperen, P. Allman, M. Bell, W. Beresford, J. Clay, G. Evans, M. Dorey, K. Gilchrist, A. Memon, G. Pannu, R. Walkley, M. Watson, A. Madzvamuse. Predicting and forecasting the impact of local outbreaks of COVID-19: Use of SEIR-D quantitative epidemiological modelling for healthcare demand and capacity. Published online August 2020, DOI: 10.1101/2020.07.29.20164566. Subsequently under review in Int. J. Epidemiol. Research supported by Research England/HEIF Grant [G1]
[G1] Leverhulme Trust (Unravelling new mathematics for 3D cell migration, Madzvamuse, A. (PI), Styles, V. (Co-I), Venkataraman, C. (Co-I); University of Sussex, 09/2014-12/2017; RPG-2014-149, £258,593) .
[G2] Research England/HEIF (COVID Rapid Response – HEIF Programme, Madzvamuse, A. University of Sussex, 04/2020 – 12/2020, £75,280).
4. Details of the impact
The mathematical modelling outlined above has supported COVID-19 control measures at the levels of (1) national policy (in Ukraine) and (2) regional healthcare management in East and West Sussex, and Brighton & Hove (in the UK).
4.1 Impact on the design and implementation of COVID-19 control measures in Ukraine
In Ukraine, the majority of scientific research is done in research institutes of the state-funded National Academy of Sciences of Ukraine (NASU). Prior to emergence of COVID-19, there was no dedicated scientific committee in Ukraine that specialised in modelling epidemics and advising government on strategy. To address the growing problem of COVID-19 and to develop strategies for its containment and mitigation, in early April 2020, the National Security and Defence Council of Ukraine (NSDCU) approached the NASU, which then created the Working Group on “Mathematical modelling of problems related to the coronavirus SARS-CoV-2 epidemic in Ukraine” (equivalent of UK’s SAGE group), chaired by Dr Igor Brovchenko. Since April 2020, this Working Group provides weekly or bi-weekly forecasts of cases, deaths and recoveries for each of Ukraine’s regions to the National Security and Defence Council of Ukraine and the Cabinet of Ministers, who then use those forecasts for policy decisions. It is the only scientific committee in Ukraine that directly communicates with the government with regards to monitoring the dynamics of COVID-19, provides forecasts, and models the effects of different types of interventions.
Building on their previous work on COVID-19 dynamics in the UK [R1], Blyuss and Kyrychko worked closely with Dr Brovchenko to develop a mathematical model of COVID-19 dynamics [R3] that was based on detailed clinical and epidemiological data collected by the Ukraine’s Ministry of Health. Some of the early results of this work featured in a national press conference given to Ukrainian journalists by the Working Group of the National Academy of Sciences of Ukraine on 28 May 2020, where the Chair of the Working Group explicitly stated that the model developed jointly with researchers at Sussex is far superior and more accurate [S1] compared to the basic model used at that point. This new model allowed its users to (i) account for regional differences in population age structure and mixing, and (ii) identify which control measures – such as lockdowns or targeted actions to reduce mixing among the working-age population – lead to the most significant reduction in disease burden. The President and the Head of the Working Group of NASU confirm in their gratitude letter [S5] that the set of “Specific measures that were subsequently introduced on the basis of these results” included:
On 13 June 2020, Ministry of Health introduced a requirement for local authorities to modify working hours at local companies to reduce mixing between working-age people during rush hour [S2].
On 20 June 2020, the Cabinet modified its guidance and allowed regional administrations to make local decisions on anti-epidemic measures and local lockdowns for different regions depending on their current levels of infection, starting from 22 June 2020 [S3, S5].
On 22 July 2020, the Cabinet introduced the tiered system (“green”, “yellow”, “orange”, “red”) for characterisation of severity of epidemiological situation in each of Ukraine’s 25 major administrative regions, starting from 1 August 2020. This tiered system was designed based on the following quantitative measures: the percentage of hospital bed occupancy, the rolling average of the percentage of positive PCR tests per capita, the local growth rate of cases, and the per capita weekly number of administered PCR tests. On the basis of these quantitative measures, restrictions and/or closure of shops, hospitality, sports venues, schools, universities, colleges, public transport were instigated [S4-5].
These measures meant that the Ukrainian Government could:
implement epidemic control measures without a nationwide lockdown; and
make the best-informed policy decisions they could, and that, in the government’s opinion, their interventions were as effective as possible in slowing the spread of the pandemic.
The President and the Head of the Working Group of NASU confirms these impacts and the work’s continuing legacy: “The results of this research and the associated recommendations have been and are being used by the Government of Ukraine and the National Security and Defence Council of Ukraine when making decisions on the strategy of containment of [the] COVID-19 epidemic in Ukraine” [S5].
4.2 Impact on decision making and care provision in the Sussex region
In response to the COVID-19 pandemic in the Sussex region, the Sussex Health and Care Partnership developed a Gold Command structure which posed modelling questions of strategic operational significance to the Local Health Resilience Partnership (LHRP) covering East Sussex, West Sussex, and Brighton & Hove (with a combined population of 1.7 million).
While national-scale planning for COVID-19 is underpinned by the modelling conducted by SAGE-NHSE, local decision making and planning requires finer resolution approaches. As a result, leaders from Public Health Intelligence approached Madzvamuse and his team to create a consortium, known as the “Sussex Modelling Cell (SMC)”, to undertake COVID-19 epidemiological modelling that is specific to the region [R5]. The work addressed questions of strategic and operational significance for local decision making throughout the pandemic.
a. Forecasting the impact of COVID-19 secondary waves within Sussex [S6-7, S10]. By manipulating the reproduction rate (R number), the model results [R5] showed that if a second wave was to happen it could cause up to ten times the strain on hospital demand compared to the experience that incited the first national intervention. On 20 July 2020, this was the basis of LHRP’s decision to not reduce the available wards for COVID-19 patients, and for funding to be provided for a one-year postdoctoral research assistant to focus on the future of COVID-19 within Sussex [S6]. Kate Gilchrist, Head of Public Health Intelligence at Brighton & Hove City Council, said “[national modelling] was not an accurate representation of what was happening at the time, as we found out when we started using the modelling outputs the university team [R5] derived, and so without the Sussex Modelling Team we could have easily mis-calculated the necessity for wards and body storage inducing monetary and resource mismanagement” [S10].
b. Translating the reasonable worst-case scenario (RWCS) SAGE national forecast [S8, S10]. With the success of the second wave modelling, on 11 September 2020, Madzvamuse’s team undertook research to aid the translation of the SAGE national RWCS document to reflect the impact in Sussex. By working with the official sensitive SAGE documents and through modelling, they demonstrated that not only should Sussex expect the peak of hospital demand later than nationally modelled, but in fact Sussex was already experiencing less hospital demand than what was expected from the RWCS document. On 6 October 2020, this underpinned LHRP’s decision that healthcare capacity was accounted for until at least the end of January 2021 and no changes were required [S8]. Graham Evans, Head of Public Health Intelligence at East Sussex County Council, referred to the RWCS modelling and said “After reviewing the information and the presentation, Mark Angus (Director of Urgent Care System Improvement, Sussex Clinical Commissioning Group (CCG)) said ‘this work has been fundamental to how we have developed our plans for our system and how we monitor our systems as part of our incident management and resilience management.’.” [S10].
c. Forecasting demand and capacity for the death management cell (DMC) [S10]. Following the RWCS modelling, on 4 November 2020 the DMC, a subgroup of the Sussex Resilience Forum dealing with excessive deaths, approached the SMC to understand the demand for the potential body storage requirements over the winter period. Madzvamuse’s team provided this information and on 7 December 2020 the DMC decided to renew their body storage contracts for the winter period. The forecasting for the DMC is particularly important as they need at least a month’s notice of any large changes in deaths, which would mean the ability to forecast reliably at least two months in advance, something which is not attainable using the national modelling. Regarding the modelling of death management, Jacqueline Clay, Principal Manager, Public Health and Social Research Unit at West Sussex County Council, said “Without the University of Sussex Mathematics Team, we would have used short term monitoring of deaths by underestimating the lag between infection, illness and death; this would not have provided a sufficient time period to adjust plans. However, the [DMC] knows, ... that the research and forecasting done here was reliable, easily understandable and accessible”, and “Halogen [the online tool developed by Sussex based on [R5]] gave me the ability to understand how the mathematical modelling works, something that is crucial for having the confidence that the modelling techniques work…” [S10].
d. Urgent Community Response (UCR) service within West Sussex [S9-10]. With the growing hospital demand throughout the pandemic, there was a need to understand the added burden COVID-19 was having on acute hospital care and post discharge services. The UCR service tries to minimise the burden in acute care by (i) providing potential patients with care at home or in other care establishments (like care homes) and (ii) providing extra support to discharged patients who may need it. The research provided by Madzvamuse’s team projected the number of patients discharged throughout the winter period, which – in combination with the discharge pathway analysis by Phil Allman, Head of Performance, Planning and Intelligence for West Sussex at the Sussex CCG – provided the Sussex CCG with the information to appropriately allocate resources and successfully secure an additional £1.63 million to deal with the burden of COVID-19 within West Sussex [S9]. In addition to the typical winter services needed, this extra grant almost doubled the amount requested last year. Phil Allman said “Without the Sussex Mathematics Team [R5], I would have simply used the national model outputs and scaled them to fit the Sussex regional numbers. This would have been highly ineffective due to the different impact COVID-19 has had nationally in comparison to Sussex, as well as the crude approximation from the reduction in magnitude of numbers. This will not only have either majorly under- or overly-estimated the funding needed, but would have caused the wrong allocation of resources, potentially causing major issues later in the winter period” [S10].
5. Sources to corroborate the impact
[S1] National press conference for Ukrainian journalists by the Special Committee of the National Academy of Sciences of Ukraine (28 May 2020) https://www.youtube.com/watch?v=VWSRpI1-lAI (research mentioned 20m35s – 21m30s). [in Ukrainian, translated transcript of segment supplied].
[S2] Ministry of Health of Ukraine introduced a requirement for local authorities to reduce mixing of working age people by means of modifying working hours and shifting rush hours https://covid19.gov.ua/karantynni-zakhody [in Ukrainian]
[S3] Ukraine’s Cabinet of Ministers’ directive on delegating decisions on local lockdown measures to individual regions (22 Jun 2020): https://www.kmu.gov.ua/npas/pro-vstanovlennya-karantinu-z-metoyu-zapobigannya-poshirennyu-na-teritoriyi-ukrayini-gostroyi-respiratornoyi-hvorobi-covid-19-sprichinenoyi-koronavirusom-sars-cov-i200520-392 [in Ukrainian]
[S4] Ukraine’s Cabinet of Ministers’ Directive (22 July 2020) on the introduction of tiered system of epidemic monitoring from 1 Aug 2020: https://www.kmu.gov.ua/npas/pro-vstanovlennya-karantinu-ta-zapr-641 [in Ukrainian, summary from the Ministry of Health together with its English translation is supplied].
[S5] Letter of gratitude from the Special Committee of the National Academy of Sciences of Ukraine detailing the contribution of the work of Kyrychko and Blyuss to mathematical modelling of COVID-19 in Ukraine, including the specific list of anti-epidemic measures that were subsequently implemented by Ukraine’s Cabinet and the National and Security Defence Council of Ukraine (26 Oct 2020) [scanned copy supplied].
[S6] Letter documenting supply of Madzvamuse and Van Yperen support to SMC (28 Jul 2020).
[S7] Halogen: Forecast the local impact of COVID-19. Toolkit developed by Madzvamuse, Van Yperen and others to forecast the impact of COVID-19 using their research in an interactive manner: https://alpha.halogen-health.org.
[S8] Action log after the RWCS presentation at the LHRP (9 Oct 2020). Action number 022 (p5) shows the decision to show the official sensitive to Madzvamuse and Van Yperen. Action number 032 (p1) shows that the decision to keep the same number of hospital wards open had been made.
[S9] UCR proposal (5 Oct 2020). Madzvamuse’s and Van Yperen’s modelling contribution is referenced as “the winter demand capacity modelling” in The Requirement section on p4.
[S10] Collection of testimonial letters from Brighton & Hove City Council, East Sussex County Council, West Sussex County Council, Sussex Clinical Commissioning Group (Jan/Feb 2021).