Immunity to SARS-CoV-2 in Africa

Continuing epidemic waves of COVID-19 are anticipated in many countries because of emerging viral variants, the moderate efficacy of vaccines being implemented in many countries, waning immunity and incomplete vaccine coverage.

The protective efficacy and longevity of immune responses induced by SARS-CoV-2 infection and vaccines vary markedly between individuals and populations. Knowledge on immunity to SARS-CoV-2 in African populations, and factors that impact on immunity, is very limited but is important for understanding COVID-19 morbidity and prevention in the Africa region and globally. Repeated exposure to malaria, intestinal parasites, and respiratory viruses, as well and specific nutritional deficiencies are common in sub-Saharan Africa, and can impact on innate and adaptive immunity to influence the magnitude and longevity of immunity.

As part of an international collaborative program, this project will investigate immunity in cohorts of naturally infected and vaccinated individuals in Malawi (central Africa) and address important knowledge gaps. The project will involve laboratory based studies in Melbourne that assess the acquisition and longevity of immunity generated by SARS-CoV-2 infection and vaccination and determine how malaria and intestinal parasite infections, undernutrition, and anemia impact on immunity.

We will use a comprehensive range of immunoassays including quantification of antibody magnitude (subclasses and isotypes), neutralizing antibodies to different variants, avidity and antibody-dependent cellular cytotoxicity. Additionally, studies will profile specific epitopes targeted by immunity and their relationship to immune escape by virus variants.

The overall objective of this work is informing strategies to improve protection from COVID-19, and identifying those most at risk, by understanding key gaps in natural and vaccine induced immunity.