Los Angeles County, the country's most populous local jurisdiction, yesterday reimposed a general face mask mandate for people in indoor public places, whether or not they have been vaccinated against COVID-19. The Department of Public Health cited recent increases in cases, most of which involve the especially contagious delta variant of the coronavirus.
"This is an all-hands-on-deck moment," said L.A. County Health Officer Muntu Davis, who warned that further restrictions may be necessary if cases continue to rise. "Community transmission of COVID-19 has rapidly increased from Moderate to Substantial, based on the trend in daily new cases of COVID-19," the health department says. "Wearing a mask when indoors reduces the risk of both getting and transmitting the virus. This additional layer of protection can help to slow the spread and does not limit business occupancy and operations."
It seems quite unlikely that the marginal benefit from requiring vaccinated people to wear face masks, which contradicts current advice from the Centers for Disease Control and Prevention (CDC), is worth the burden it imposes on them. The mask order, which takes effect just before midnight on Saturday, could even undermine public health by weakening the incentive to get vaccinated.
"While emerging data affirms that fully vaccinated people are well protected from severe infections with Delta variants," the health department says, "people with only one vaccine are not as well-protected, and there is evidence that a very small number of fully vaccinated individuals can become infected and may be able to infect others." As CDC Director Rochelle Walensky has noted, the evidence indicates not only that vaccinated people are unlikely to be infected but also that the rare cases of "breakthrough" infections involve relatively low viral loads. That means vaccinated people are unlikely to pass on the virus even if they defy the odds by becoming infected.
According to a Los Angeles Times tally, the seven-day average of newly identified cases in L.A. County rose sixfold between June 15 and July 15, from fewer than 200 to more than 1,000. While that's a big increase, the current average is still 93 percent lower than the number reported in mid-January. Hospitalizations also are on the rise, although daily deaths remain far below the levels seen earlier this year. Between December 7 and June 7, the Times notes, "the unvaccinated accounted for 99.6% of L.A. County's coronavirus cases, 98.7% of COVID-19 hospitalizations and 99.8% of deaths."
The health department does not cite any evidence that vaccinated people have contributed to the upward trend in cases by transmitting the virus. But since the risk that vaccinated people "may be able to infect others" is greater than zero, it figures, an "additional layer of protection" is warranted. Which makes sense, as long as you attach no weight to the discomfort and inconvenience imposed on people who have gotten their shots or the impact that the indiscriminate mandate is apt to have on people who have not been vaccinated yet.
For young, healthy residents who understand that they face little personal risk from COVID-19, the freedom to eschew masks may be one of the most appealing aspects of vaccination. So far 61 percent of Los Angeles County residents 16 or older are fully vaccinated, and this mask rule does not seem like a good strategy for pushing that number up.
COVID-19 cases are rising not just in Los Angeles County but across the state and the country. In California, the seven-day average (per Worldometer) has tripled since June 15, from fewer than 1,000 cases to more than 3,000. That is still 93 percent lower than the number recorded in mid-January. The seven-day average of daily deaths, 23 as of yesterday, is down 96 percent since late January. Nationwide, the seven-day average of newly identified cases more than doubled between June 15 and July 15, but it is still down 95 percent since mid-January. The seven-day average of daily deaths has risen slightly from a week ago, but it remains 92 percent lower than the number reported in late January.
It's true that Los Angeles County has seen a bigger increase in COVID-19 cases than many other parts of the country. But that does not mean forcing vaccinated people to wear face masks is a sensible or effective response, especially in the absence of evidence that they are playing a significant role in that trend.