Which face masks do the best job?
Study ranks all, from N95s to bandannas
Study finds that surgical and homemade cotton coverings work well to block respiratory droplets, but that folded bandannas and fleece gaiter masks are poor choices.
That bandanna might make you look like a cool outlaw from an old Western movie but it’s largely ineffective in slowing the spread of the coronavirus, according to a new study.
A group of researchers at Duke University tested 14 different types of common face masks to determine which work best to stop the transmission of respiratory droplets during regular speech — and which are practically useless.
Fitted N95 masks, usually reserved for health care professionals, came out on top of the rankings, while threelayer surgical masks and homemade cotton masks also performed well.
But the study, published Friday, found that folded bandannas and knitted masks offered inadequate viral control, while neck fleece — which are often used by runners
city’s Fire Department.
“We are going to be living with this for some time,” Breed said. “That’s money that I wish we could divert to other things, but unfortunately this is the reality of today. And I hope that’s not the reality of our next budget cycle.”
Nearly $183 million will go toward housing, shelter and medical programs for the city’s homeless population and for hotels reserved for people who cannot safely selfisolate following a coronavirus diagnosis.
Another $45.8 million will go toward food and human services programs, including a $16 million expansion of the city’s public Pit Stop restrooms.
A total of $16.5 million is set aside for operations at the city’s central COVID Command Center, which also handles multilingual outreach to nonEnglishspeaking residents.
Breed’s budget allocates almost $185 million for “health operations,” a broad category that includes funding for coronavirus testing, personal protective equipment, contact tracing and targeted outreach for vulnerable communities. Testing represents the largest share of the health operations budget, at nearly $56 million.
The city’s pandemic spending plan assumes the virus tapers off in the coming months. If it doesn’t, or if cases surge to the point of overwhelming hospital systems, more money will be required.
“It’s important to remember that this funding really assumes we don’t see any major surges. If that happens we will need to divert even more resources,” Breed said. “It also assumes that we will continue to be reimbursed by FEMA, and you all know how uncertain the federal government has been, unfortunately.”
Dr. Grant Colfax, the city’s public health director, joined Breed at the briefing to provide an update on San Francisco’s latest numbers.
As of Tuesday morning, the city recorded 7,692 confirmed cases and 67 deaths due to COVID19. There are currently 88 people hospitalized in the city, a roughly 25% decline compared to the city’s peak on July 28 and July 30.
San Francisco’s coronavirus contagion rate has reached a level at which the outbreak is considered on the decline, Colfax said. The reproduction ratio is just below 1.
This indicator is an epidemiologic metric on contagiousness, estimating the average number of people that one infected person will pass the virus to. An outbreak is expected to end if the number is less than 1, according to the Centers for Disease Control and Prevention.
“We need to see that trend continue so we get much, much lower,” he said.
The number of people hospitalized for COVID19 has been declining in the Bay Area and statewide since late July.
Statewide, 12,431 new cases were reported as of Monday night. That is the largest singleday increase for the state, but the number is likely unusually high because it includes previously underreported cases from July.
The Bay Area reported 64,304 cases and 928 deaths since the pandemic began, as of midday Tuesday. Altogether, California has had 577,643 cases and 10,516 deaths.
The global count of known infections was more than 20.1 million as of Tuesday. More than half of cases are from the U.S., India and Brazil, according to Johns Hopkins University data. Average new cases per day in the U.S. have declined but still number over 54,000, compared to almost 59,000 in India and nearly 44,000 in Brazil.
The recent statewide data glitch with the state electronic case reporting system, known as CalREDIE, did not affect San Francisco’s projections, according to Colfax.
“We are confident in our ability to estimate the effective reproductive rate based on the hospitalization data in the city,” he said. “The case rate — the number of people diagnosed with COVID19 based on testing — that number could change based on the correction from the state.”
The state is expected to correct its data Wednesday.
Colfax attributed the city’s steadying case count to intensive work with community members, key stakeholders, physicians, clinicians and people in the neighborhoods hardest hit by the pandemic.
He added that the city would emphasize outreach over enforcement in making sure residents and businesses comply with the health orders and recommendations from the Public Health Department.
Breed said the city was still short of its goals and urged residents to resist letting their guard down.
“We still have a long way to go,” she said. “As tired as we are of doing what we need to in order to keep one another safe, we have to start getting comfortable with it. We have to start changing our behavior. It really is what’s going to make the difference.”
Urging people to refrain from social gatherings, she noted that Tuesday was her birthday.
“I wish I could have a birthday party,” Breed said. “I’m going to socially distance myself and talk to people on Zoom. That’s what we need to do. Just imagine if we all did our part where we would be today.”
Elsewhere in the Bay Area, Marin County reported 16 active COVID19 hospitalizations on Tuesday, including three inmates from San Quentin, marking its lowest total since June 28.
Citing sharply declining coronavirus transmission rates in the county, county officials allowed nail salons, massage therapy and aesthetic, cosmetology and skin care services to reopen outdoors on Tuesday. The county also plans to allow hotels and shortterm rentals to open Aug. 24 if virus cases remain below 200 per 100,000 residents through Aug. 21.
Marin County officials on Friday will apply for a state goahead to reopen county schools, Public Health Officer Matt Willis said.
He told the Board of Supervisors the earliest schools could open would be Sept. 8, with sitespecific protection plans needed for each facility.
Santa Clara County officials said Tuesday that the number of patients hospitalized with COVID19 has stabilized since late July, holding at just under 200. The county’s average positivity rate for the past three weeks is 4.82%, with residents in the 18to34age group making up the largest demographic.
Officials plan to open a largecapacity, drivethrough testing site at the county fairgrounds later this month. There will be dedicated lanes for people who speak Spanish and people arriving on foot or bicycle.
San Mateo County reported 43 cases of the coronavirus, bringing its total to date to 6,428 cases. The county also recorded an additional two deaths for a total of 122 fatalities so far.
Health officials in Contra Costa County said there were 38 deaths in the last two weeks, bringing the death toll in the county to 146.
“I wish I could have a birthday party. I’m going to socially distance myself and talk ... on Zoom.”
Mayor London Breed