Herd immunity may indeed have slowed the transmission of COVID-19 in Manaus, Russo says, but this isn’t a strategy that we should be striving for elsewhere. Roughly three million people would die in the process in the US alone, and researchers worry that COVID-19 may lead to long-term health issues even in some people who had mild or asymptomatic cases.
“There will definitely be an excess of deaths and almost certainly an excess of intermediate and long-term health consequences,” Russo says. “There may be ramifications to getting infected that aren’t initially realized from a health point of view, but might rear their ugly head months, years, or decades from now.”
Additionally, most places–even those with severe COVID-19 outbreaks–are nowhere close to achieving herd immunity; only about 27 percent of New Yorkers tested in a recent study had positive antibody tests. However, Russo says relying on public health measures like masks, frequent hand washing, and social distancing could give us a similar effect to herd immunity.
“I’d much rather have zero percent of people infected and 80 to 90 percent of people rigorously using masks. That ship has left the harbor, unfortunately,” he says. “But certainly, minimizing the number of people infected and using the public health measures as a surrogate for protection until we get to the vaccine is key.”