Deborah Birx, the White House's coronavirus task force coordinator, toured North Dakota this fall when the state was overwhelmed by one of the country's worst Covid-19 outbreaks. While praising the state's testing efforts, she was dismayed at the noticeable lack of face masks in public spaces. "This is the least amount of mask use we've seen in retail stores in any place we've been," she said at a news conference on October 26th.
North Dakota, which did not require masks at the time, had the lowest mask wear rate in the country, according to survey data in October.
North Dakota isn't the only state lagging behind in a mask policy during a major outbreak, however: eight of the top ten states that recorded the highest new cases per capita in October had no widespread mask mandate showing below. (Several of these Great Plains and Midwestern states were spared significant outbreaks of the virus through the fall.)
Youyou Zhou for Vox
But the dramatic fall and winter surge in Covid-19 across the country has forced some states to change course. On Nov. 8, Utah implemented a mask mandate as the number of new daily Covid-19 cases continues to grow across the state and across the country. Several other states have since implemented or tightened mandates, including Iowa and North Dakota. Thirty-seven states now have mandates, according to the AARP.
And on December 4, the CDC issued a new recommendation that people should wear masks at all times around the house unless they are at home.
In the course of the pandemic, America was involved in a massive and uncontrolled mask experiment: some jurisdictions have implemented and enforced mask mandates; others opposed them when the public health guidelines were politicized. President Donald Trump has repeatedly questioned and even despised the use of masks, and several Republican governors have followed suit. President-elect Joe Biden, meanwhile, has called for a national mask mandate, urging Americans to wear masks for the "first 100 days" he is in office while vaccines are introduced.
Because of the different approaches at the country level, researchers can now analyze the results of an experiment that they would never have received permission to conduct. New research from Kansas and Tennessee suggests that mask mandates not only prevent the spread of Covid-19, but can also lessen the severity of the disease and reduce the number of serious cases that require hospitalization. Other findings support the argument that more and more public health experts are arguing: masks are still one of our cheapest and most effective tools for fighting the pandemic – if worn consistently.
"When you're not in intensive care, we only have tried and tested public health measures such as social distancing, hand washing and masks," said Vin Gupta, an intensive care pulmonologist and associate professor at the Institute of Health Metrics and Assessment from the University of Washington. "We bear the brunt of the fact that these things are poorly implemented."
"You are less likely to get Covid-19 if you wear a mask," says Donna Ginther, an economist and director of the Institute for Political and Social Research at the University of Kansas. And "even if you get sick with a mask on, you're less likely to get terminally ill."
Let's review some of the latest research on mask mandates and what they mean as we head into one of the most dangerous seasons of the pandemic.
New evidence from Kansas and Tennessee that mask mandates control the spread of Covid-19
Intriguing evidence of the effect of mask mandates on controlling the spread of the virus comes from Kansas. In July, Laura Kelly, the Democratic governor of Kansas, issued a mandate requiring everyone to wear a mask in public places where 6 feet of social distance could not be maintained. It sparked an immediate outcry from the Conservatives. Due to a state law passed in June allowing counties to replace the governor's emergency powers, 81 out of 105 counties have rejected the mask mandate altogether, and only 21 counties have chosen to enforce it.
Two researchers from the University of Kansas analyzed what happened next.
Youyou Zhou for Vox
Ginther, the economist involved in this analysis, noted that in the counties where the wearing of masks was compulsory, new cases remained roughly stable. But in the counties with no mandate they doubled, even after checking the number of times people left their homes. "We were stunned by the strength of the effect," she says.
The health officer for Johnson, the largest county in the state, was so impressed that he asked Ginther to share her work with the Board of County Commissioners, even though it has not yet been peer-reviewed or written on paper. She is currently working on the publication of the results.
Ginther says growth in the cases only slowed down 12 weeks after the mandates went into effect. But she thinks her results are conservative. "A 50 percent reduction in cases is likely a lower bound on the actual effect of wearing a mask," she says. "If you had 100 percent compliance, I would expect an even greater effect."
Other researchers have made related results. A nonprofit group called Prevent Epidemics recently released a report that found coronavirus cases were declining after mask mandates in Alabama, Oklahoma, South Carolina and Texas. The CDC found that after a mask mandate was introduced, Covid-19 cases decreased by 75 percent in Arizona. Conversely, when home stay orders were canceled, cases rose 151 percent, showing that behavior has a significant impact on virus transmission.
New findings from Tennessee are not only slowing the spread of the virus, but also showing that mask mandates can reduce the severity of the virus. An article by researchers at Vanderbilt found that in Tennessee hospitals where at least 75 percent of Covid-19 patients were from countries with mask requirements, hospital stay rates for coronavirus were the same as in July. In hospitals where fewer than 25 percent of patients come from mask-mandated locations, hospital admissions are 200 percent higher. In addition, according to the researchers, hospitals in areas with mask requirements and other mitigation strategies are "much better able to serve the full spectrum of community health needs, not just Covid-19 patients."
Mask mandates lead to more people wearing masks
While not always followed, mask mandates appear to be an effective tool in encouraging behavior change. The Institute of Health Metrics and Assessment (IHME) at the University of Washington found in August that mask use increased 8 percentage points after mask mandates and 15 points after those mandates were enforced.
According to IHME, only around 65 percent of Americans currently wear masks on a regular basis. In Singapore, for example, around 95 percent of people wear masks and have one of the lowest coronavirus death rates in the world. "We know that countries that wear masks are much better off," said Ali Mokdad, chief strategy officer for public health at the University of Washington.
Thirty-three states and Washington, DC implemented nationwide mask mandates between April and August. During the same period, more and more Americans began to wear masks on a regular basis. This is the result of a weekly survey launched by the data intelligence company Premise in mid-April.
Youyou Zhou for Vox
There is one limitation to all of the above analyzes: they only observe the behavior, which means that they can detect associations – such as case numbers that fall after the introduction of mask mandates – but no causes. The gold standard to prove this was a randomized controlled trial. However, ethical concerns make it difficult to design this study in a pandemic.
Even without randomized trials, Rebekah Gee, a public health policy expert and secretary for the Louisiana Department of Health, says the evidence "confirms what public health experts have known since the early days of this pandemic is that masks work."
Masks could save 130,000 lives by February, but more Americans would need to wear them consistently
A study published by IHME's forecasting team in Nature Medicine on Oct. 23 modeled current public health interventions – projected case numbers based on current behavior – and found that using a universal mask could save up to 130,000 lives by the end of February 2021 could.
Therefore, according to Mokdad, it is important to have clear and consistent recommendations for wearing masks. He adds: “We never discuss seat belts. Is it okay if only 80 percent of people wear them? We say everyone should. "But while he would prefer 100 percent of people to wear masks, Mokdad says at this point, any incremental increase in mask use is" a feast for me. "
Unfortunately, in many parts of the United States, mask use is actually decreasing. For example, in Florida, which had some serious spikes this summer, 70 percent of people wore masks in August, according to Mokdad. Now it's only 65 percent. "Wearing masks was more a response to fear than good, persistent behavior," says Mokdad.
Vox analyzed the relationship between the frequency of mask wear from the Premise survey data and Covid-19 cases in states from April to October. As the following graphs show, more people are now wearing masks in states with mandates where cases rose sharply in the spring. In these states, where more and more people are wearing masks on a regular basis, it is less likely to see another large increase in some cases.
Youyou Zhou for Vox
Although mask use has increased in many states, the entire nation is on a troubling path with new daily cases, hospitalizations and deaths increasing. Mokdad says he is very concerned about the holidays. "When we are with our loved ones – our grandparents, our children – do you want to sit down at a table and risk the people who matter most to you, or do you want to wear a mask?" IHME models predict that some US states could reduce the number of future Covid-19 deaths by about 50 percent if they started using more masks from now on.
The stakes to get this right are high – not just for the holidays, but for the rest of the pandemic, however long that may be.
Anthony Fauci, director of the National Institute for Allergies and Infectious Diseases, recently reiterated Biden's call for a national mask mandate. "If you don't want to shut down, at least do the basic things," Fauci told the editor-in-chief of JAMA, "whose flagship is wearing a mask."
Leana Wen, a doctor and former Baltimore City Health Commissioner, says wearing masks allows you to do things rather than seeing a mask mandate as something that takes away your freedom, as anti-mask protesters have claimed. “When everyone wears a mask, transmission is kept low so businesses and schools can stay open.
"If you want a more normal life, we have to adjust our behavior instead of locking ourselves away," says Ginther. "Masks are rising to the top as an approach that we as a society can take to have a more open economy but not make everyone sick."
Lois Parshley is a freelance investigative journalist. Follow her Covid-19 coverage on Twitter @ Loisparshley.
Editor's note, November 7th: Due to a data error, an earlier version of the chart of the increases in Covid-19 cases in October did not include Hawaii and Louisiana was not classified as a mandate. In fact, Louisiana implemented a mandate in August. The chart has been updated to reflect these changes.
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