Achieving Population Immunity and Vaccine Protection Against COVID-19

By Catherine Morrow

The Lancet has published commentary by infectious disease epidemiologist Ben Lopman, PhD, on how to achieve population immunity to COVID-19 through widespread vaccination.

Lopman’s commentary is motivated by the SIREN study, a cohort of health care workers in England, that found the Pfizer/Biontech vaccine to be highly effective against symptomatic or asymptomatic infection with the virus that causes COVID-19. 

He also notes that vaccinated individuals were less likely to report symptoms if they did get infected with the virus, and participants who had previously contracted COVID-19 had 90 percent protection against subsequent infection, regardless of vaccination status.

Lopman and co-author Eyal Leshem, MD, from Sheba Medical Center in Israel, say that this is an “encouraging step forward in our understanding of COVID-19 vaccines” and that “COVID-19 vaccines provide a safe way of getting community transmission under control.”

Lopman and Leshem estimate that about 80 percent of the population would need to be vaccinated with two COVID-19 doses to achieve population immunity from vaccination exclusively.