When will it be safe to shop at a grocery store or show up at the office without wearing a mask? Sooner than most experts are willing to admit. If the coronavirus epidemic in the U.S. continues on its current trajectory, the need for masks outside particular local outbreak areas will pass in a matter of weeks.
One way to think about the problem is by analogy to seasonal influenza. Hardly anybody wears a mask in ordinary settings to protect against the flu, and no one is required to do so. The worst flu seasons of recent years saw an average of 220 deaths a day nationwide. The seven-day moving average for Covid-19 daily deaths hovers around 900, still considerably worse. But that’s a 78% reduction since January, and the trends are favorable almost everywhere in the country. When the 14-day rolling average of daily Covid deaths has come down below flu level, which may happen within the next month or two, we should adjust our thinking about the coronavirus accordingly.
Vaccination is the main reason for the sharp decline in Covid cases and deaths. Some three million shots are being administered each day, and once immunity has kicked in, the vaccinated are at negligible risk of being infected, never mind spreading infection. If you’ve been vaccinated, there’s almost no direct safety benefit—to yourself or others—of wearing a mask. You still have to do so only because immunity is invisible. The expectation or requirement of mask-wearing is impracticable to impose only on those who are vulnerable or may be dangerous.
At some point, however, herd immunity is achieved: Enough of the population is immune to make the risk of infection minimal in the population as a whole. Anthony Fauci puts the threshold for herd immunity at full vaccination of 85% of the U.S. population, including children. Since the vaccine has been authorized only for patients 16 and older and not all adults are willing to accept it, Dr. Fauci’s goal almost certainly won’t be reached for another year, if ever. The current figure is only 17% of total population.
Dr. Fauci’s benchmark is unreasonably high. He ignores that many unvaccinated Americans—perhaps as many as 120 million, as seroprevalence studies suggest true incidence levels to be three to 20 times captured infections—have immunity owing to prior infection. A recent large-scale Danish study finds that prior infection provides approximately 80% protection to patients younger than 65 and 47% protection to those older. That difference is why it’s important to prioritize the elderly for vaccination, as U.S. authorities have done. Because of this combination of factors, we will likely surpass 50% combined immunity within the next week or two.