In collaboration with colleagues from King’s College London and UCL, she has published a study on Wellcome Open Research that is undergoing peer review and that estimates how deaths from the COVID-19 pandemic will fluctuate in coming months across seven European countries.
Following the introduction of measures to reduce the spread of COVID-19 such as social distancing, some countries are beginning to report a slowed rate of growth or a decline in the numbers of people testing positive each day for COVID-19. This suggests that countries are at or have past ‘the peak’ of infections. In order to provide insight into the future patterns or cycles of the pandemic, Dr Moran used a modelling approach to estimate the susceptible population, which is the number of people at the start of the outbreak who would eventually become infected.
‘When I first ran the code from various models on data from different countries I was interested to see how small the actual infected population was compared to the whole population,' Dr Moran said. 'I then started to wonder about estimating this susceptible population further down the line of the pandemic to see how this could help understand smaller peaks of infections that might happen in the future.'
Using different epidemiological models, including a new dynamic causal model developed by a former colleague, and assuming that those who have contracted COVID-19 and recovered from the disease are immune, the study estimated that on average across the countries 6.4% of the total population would be immune after the first peak. This percentage ranged from 19.6% of population in the UK to 4.7 % for Germany.
Based on these estimates and by re-running the models on the ever decreasing figures for susceptible populations after each peak, the study suggested that there would be several more peaks of infection in the future which get smaller and smaller until herd immunity has been reached. Herd immunity is when 60% of the population is immune and there is sufficient resistance to the spread of a contagious disease within a population. This is assuming that nobody has innate immunity, which too remains to be fully determined.