REinfection in COVid-19 Estimation of Risk (RECOVER)

Studies done with human coronaviruses (hCoV) have shown that antibodies rise on average 12 days after the onset of symptoms, are higher with more severe disease and seem to decrease the risk of reinfection for 1-3 years. Participants challenged with the same virus (hCoV 229E) 8-12 months after being infected with hCoV still developed symptoms and shed virus. Thus, if reinfection, whether symptomatic or not, occurs with viral shedding, achieving natural herd immunity against COVID-19 is unlikely. Awaiting a vaccine that would protect the entire population, there is hope that short-term natural immunity following natural disease can be achieved. However, we do not know at this point in time if COVID-19 positive patients in whom we detect an immune response have a long-lasting response and if this response protects them against reinfection and viral shedding There is a need to know these answers to plan for future actions. If an antibody response is not long-lasting and protective against viral shedding, then herd immunity is not a goal to aim for, as vulnerable patients will remain at risk; individuals having recovered from the disease may get re-infected and be a source of infections for others. In such a case, other non-pharmacological interventions will be necessary until an efficacious vaccine or therapeutic agent becomes available. We aim to estimate the risk of reinfection with SARS-CoV-2 in healthcare workers (HCW) who have already been infected with COVID-19 and aim to study antibody response and levels in asymptomatic and symptomatic HCWs with confirmed COVID-19 reinfection over a 1-year period. Findings from this study will allow public health decision-makers to decide on future strategies for deconfinement/reconfinement and pandemic management. The 6-month results will be shared with public health. Showing that COVID-19 does not protect against mild reinfection or viral shedding will completely change the paradigm under which we are operating currently.