Do mask mandates work? Bay Area COVID data says no.

In early June, during an uptick in COVID-19 cases, Alameda County was the only county in the Bay Area to bring back an indoor mask mandate.

At the time, county health officer Dr. Nicholas Moss said, “Put back our masks on gives us the best opportunity to limit the impact of a prolonged surge on our communities.”

But regional case data provides no discernable evidence that the rule, which was lifted on June 25, has achieved that goal.

The graphs below compare Alameda County’s seven-day average case rate over the past two months to rates in neighboring Contra Costa, Santa Clara and San Francisco counties. Contra Costa and Santa Clara, in particular, are natural comparisons to Alameda, as they have similar vaccination rates and demographics. San Francisco, across the bay, provides an additional landmark. All data comes from the California Department of Public Health.

The case rate curves for Alameda and Contra Costa counties are nearly identical. Since neighboring counties are similar in many ways, if the masking policy had an impact on the results of the pandemic, one would expect to see some sort of discrepancy in the graph.

San Francisco and Santa Clara had higher case rates than Alameda County throughout the current outbreak, including the pre-mask term. Once the mandate was introduced, the three counties all followed the same trend line, casting doubt on whether the mask mandate did anything to curb transmission at the community level.

SFGATE emailed Moss these graphs and asked if he could point to any evidence that his county’s mandate had had an impact on reducing the number of cases.

“We believe the recent mask order has contributed to the improvements we are currently seeing with COVID-19 in Alameda County,” Moss said in a statement. “Conditions are more stable now than when the Order was established.”


“Published evidence shows that high levels of community masking reduce transmission rates and survey data has shown an increase in masking over the recent order period,” he added. “In fact, Alameda County saw higher masking rates than anywhere else in the country at the time.”

The Alameda County Health Department did not respond to follow-up questions about how Moss determined his county had higher masking rates than anywhere else in the country, and how, if that claim was true, the graphics would not be cut against the claim that “high levels of community masking reduce transmission rates”.

The Alameda County mandate was implemented shortly after The New York Times published an article titled “Why Masks Work, But Mandates Don’t.” The article says high-quality, well-fitting masks can help minimize the risk of catching or spreading COVID-19, but community-level mandates have failed to affect case rates as the virus is so contagious that it spreads easily in the moments when people take off their masks to eat, drink or get comfortable.

After looking at the case rate charts, UCSF’s Dr. Bob Wachter — one of the region’s most cautious COVID-19 experts and a proponent of mask mandates — echoed many of the sentiments of this article, stating that the mandates do not appear to increase the “likelihood of people wearing good masks correctly. Many people find it difficult to wear an N95 for long periods of time, opting instead for inferior fabrics or surgical masks .

“If the mandate came with a requirement to properly wear a good mask (N95 or equivalent), this could demonstrate a significant benefit in preventing cases,” he wrote to SFGATE in an email. “But there’s no real application (certainly no proper masking using a good mask), which means effective masking rates probably aren’t much different across [the Bay Area counties being compared].”

If, to have a hard-hitting mask mandate, enforcement teams need to make sure people wear N95s indoors correctly, it seems like a doomed policy every time it is implemented. . It also raises the question of whether the costs of such an application would outweigh the benefits.

Residents of the San Francisco Bay Area, with high rates of vaccination and acquired immunity in the last two outbreaks, are well protected from serious illness and death. Over the past two months, Bay Area hospitalizations have fallen far short of winter omicron numbers, which may not have accurately reflected the true impact of the disease. on hospitals. Alameda County’s per capita hospitalization numbers are comparable to Contra Costa and Santa Clara.

Wachter has long pointed out that anyone who wants to limit their chances of catching COVID-19 can easily do so by wearing a properly fitted N95 when going out in public, with or without a mask mandate. It’s rare for doctors to catch the virus while wearing N95 masks, he told SFGATE, even when interacting with patients who test positive.

Wachter’s colleague at UCSF, Dr. Jeanne Noble, is also a proponent of high-risk individuals protecting themselves through prudent mask use. The mandates, she told SFGATE in April, drive people to wear poor quality masks, which “are not likely to make a measurable difference in viral transmission, so it doesn’t matter whether you or others wear one”.

“Mask mandates can create a false sense of comfort for those who really need extra protection,” Noble said in April. “The severely immunocompromised person…should use an N95 in crowded spaces when viral prevalence is high. They shouldn’t opt ​​for a cloth or surgical mask because other people around them are masked and therefore assume it’s “safe enough” to avoid the tight and uncomfortable N95.

About Dwaine Pinson

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