Antibody tests: Cause for optimism?
An astonishing 1 in 5 people in New York City may have already had coronavirus, said David Leonhardt in NYTimes.com. Researchers collected blood samples from 1,300 people in New York City and found that 21 percent had Covid-19 antibodies, leading Gov. Andrew Cuomo to speculate last week that 2.7 million New Yorkers may have survived the disease—most with mild or no symptoms. Two new antibody tests in Southern California also indicate higherthan-expected infection rates. A much higher rate of infection than indicated by officially confirmed cases might be good news, since it suggests that the death rate could be closer to 0.5 percent, not 3 or 4 percent. But a high infection rate would also indicate the virus is far more contagious than we realized, indicating that “it may be harder to contain in coming months” as restrictions are eased. If tens of millions of Americans become infected, the eventual death toll could be “catastrophic”—in the hundreds of thousands.
“Shouldn’t Covid-19’s lethality inform the response to it?” asked Jacob Sullum in Reason .com. Los Angeles County found 4 percent of 863 adults tested positive, suggesting the county’s infection count “was roughly 40 times the number of confirmed cases.” That would indicate a death rate of 0.1 percent to 0.2 percent, making Covid19 “only somewhat more deadly than the seasonal flu.” Policymakers need to modify their “cost-benefit” analyses of blanket lockdowns, which were justified by “terrifying projections” of Covid-19 deaths. It’s time for “more carefully targeted” restrictions on Americans’ “liberty and livelihoods.”
Not until antibody studies are more reliable, said Andrew Joseph in STATNews.com. Neither the New York City nor the California samplings were truly randomized, and may have tested people more likely to have been exposed than the general population. Antibody tests also have been plagued by high rates of false negatives and false positives; the FDA let more than 120 antibody tests hit the market without proof of accuracy.
It’s not even clear whether antibodies guarantee immunity, said Umair Irfan in Vox.com, so positive tests risk giving people a false sense of security. It’s true that “Covid-19 could be way more prevalent and far less deadly than anyone has realized.” But we shouldn’t give people a green light to return to public places without “much more rigorous research.”