What policy makers need to know about COVID-19 protective immunity

The Lancet
May 16, 2020 Volume 395 Number 10236 p1521-1586, e83-e89


What policy makers need to know about COVID-19 protective immunity
Daniel M Altmann, Daniel C Douek, Rosemary J Boyton
… Most of the available COVID-19 serology data derive from people who have been hospitalised with severe infection.8,18 In this group, around 90% develop IgG antibodies within the first 2 weeks of symptomatic infection and this appearance coincides with disappearance of virus,18 supporting a causal relationship between these events. However, a key question concerns antibodies in non-hospitalised individuals who either have milder disease or no symptoms. Anecdotal results from community samples yield estimates of under 10% of tested “controls” developing specific IgG antibodies. We await larger seroprevalence datasets, but it seems likely that natural exposure during this pandemic might, in the short to medium term, not deliver the required level of herd immunity and there will be a substantial need for mass vaccination programmes…