DIEP seminar by Rob de Boer
How herd immunity mitigated a deadly second wave of COVID-19 in Manaus
Manaus, Brazil, experienced two severe waves of COVID-19 deaths due to two different strains of SARS-CoV-2. Since most individuals were infected during the first wave, and the second strain nevertheless increased the mortality rates, there seems to be little cross-immunity between the two strains. Brazil has excellent public data bases providing the number of deaths due to COVID-19, and the fraction of the population having antibodies. We model this data to study why the second wave was smaller but deadlier using MCMC methods. We find that cross-immunity indeed provides little protection to reinfection, but provides excellent protection against severe disease. Hence most of the deaths during the second wave are due to primary infections caused by a large wave of reinfected individuals that are themselves well protected. We demonstrate that the first wave elicited such a form of herd immunity by artificially blocking the first wave, and observing that this intervention markedly increases the death rate during the second wave.
Rob de Boer is Professor of Theoretical Biology at Utrecht University. A major part of his work is to develop quantitative understanding of immunology by using in vivo labeling techniques and mathematical modeling, to describe the population dynamics of the major populations within the immune system. He also aims to quantify the diversity of lymphocyte repertoires, and the breadth of immune responses, by bioinformatic analysis of next generation sequencing data.
If you wish to attend this seminar online, please send an email to f.a.nobregasantos@uva.nl to receive the zoom-link.