Periodic Reporting for period 3 - ARBODYNAMIC (Coupling dynamic population immunity profiles and host behaviours to arboviral spread)
Reporting period: 2021-04-01 to 2022-09-30
In the first work package, we have concentrated on the development and use of antigenic maps, that capture the antigenic potential of different viruses. We have used the results of these antigenic maps to explore whether we can explain patterns of hospitalizations from dengue. This work has been presented at major conferences (Epidemics, EEID). We have separately used longitudinal data from dengue cohorts in Southeast Asia to capture the dynamics of immunity over time, including in response to a dengue vaccine. We showed that vaccines elucidated a lower antibody response that natural infection, that vaccine efficacy was concentrated to the first three years after vaccination and that antibodies were an excellent correlate of protection. We have also identified a correlate of protection for chikungunya virus.
In the second work package, we have used a combination of sequences and mathematical models to capture the spread of Zika virus in Thailand. We showed that Zika has been circulating endemically in Thailand for over 20 years, highlighting the potential long term consequences from the virus. We have also developed novel modelling approaches that uses genetic data to explain relative importance of human behaviour data (how we move), local environment (e.g. mosquito density), and population immunity in driving dengue spread. We were able to show that infected people move a lot less than the surrounding susceptible population; that most transmission is highly local but the occasional long distance transmission event leads to mixing of the virus after a year. These methods are now being developed for other pathogens.
Finally, we have also been applying some of the techniques we have been developing in the ARBODYNAMIC project to help in the SARS-CoV-2 response. We worked with the French government to understand the level of immunity in the population and the patterns of spread in the country. We also used population immunity estimates to capture the underlying probability of death by age. This work has all been published.