Posted on February 20, 2021 at 12:00 am by Carol Tannenhauser
By Carol Tannenhauser
The NYC Health Department is recommending that New Yorkers wear two masks—a paper one covered by a cloth one—to better stem the spread of the coronavirus, Mayor Bill de Blasio and NYC Health Commissioner Dr. Dave Chokshi announced jointly at the mayor’s weekly press conference on Thursday.
This follows the recent release of a CDC study, which found “that two masks are better than one in slowing coronavirus spread,” AP reported. “The researchers found that wearing one mask—surgical or cloth—blocked around 40% of the particles coming toward the head that was breathing in. When a cloth mask was worn on top of a surgical mask, about 80% were blocked. When both the exhaling and inhaling heads were double-masked, more than 95% of the particles were blocked…”
The new guidance comes at a time when there is growing concern about more contagious variants of the virus showing up in the city. It has become a requirement in some NYC courts. “Visitors to Manhattan federal court and other buildings in the Southern District of New York are now required to either wear two face masks or an FDA-approved N95 mask,” wrote the New York Post.
“Of all the things that we’ve learned in this crisis, maybe the most profound is the power of a mask,” Mayor de Blasio said. “What we’re saying today is time to double up. Two masks are better than one. Make it a double.”
“Masks help us face the world and each other but it’s important that we cover up correctly,” said Dr. Chokshi. “The strategies we’re sharing today will help shield all of us from COVID-19.”
The Health Department issued the following guidance on the proper selection and use of face coverings:
Use a face covering with two or three layers of material to better prevent unfiltered air from passing through. A cloth face covering over a disposable mask, is also recommended. However, people should not use two disposable masks. Wearing two of these masks does not help improve fit.
Use face coverings made of tightly woven fabric (fabrics that do not let light pass through when held up to a light source). Face coverings should be made of breathable fabric (like cotton), and not of leather, plastic, or other materials that make it hard to breathe.
Do not use a face covering with an exhalation valve as it allows unfiltered exhaled air to escape.
Make sure the face covering fits snugly against the sides of the face and fully cover both the nose and mouth, without slipping. Face coverings that fit loosely allow respiratory droplets to enter and leak out.
For New Yorkers at greater risk, the guidance recommends two masks or even considering higher-grade masks, such as a KN95 mask, which is similar in design and function to N95 masks used by healthcare workers.
A laboratory study suggests that the South African variant of the coronavirus may reduce antibody protection from the Pfizer/BioNTech vaccine by two-thirds, and it is not clear if the shot will be effective against the mutation, the companies said on Wednesday.
The study found the vaccine was still able to neutralize the virus and there is not yet evidence from trials in people that the variant reduces vaccine protection, the companies said.
Still, they are making investments and talking to regulators about developing an updated version of their mRNA vaccine or a booster shot, if needed.
For the study, scientists from the companies and the University of Texas Medical Branch (UTMB) developed an engineered virus that contained the same mutations carried on the spike portion of the highly contagious coronavirus variant first discovered in South Africa, known as B.1.351. The spike, used by the virus to enter human cells, is the primary target of many Covid-19 vaccines.
Researchers tested the engineered virus against blood taken from people who had been given the vaccine, and found a two-thirds reduction in the level of neutralizing antibodies compared with its effect on the most common version of the virus prevalent in U.S. trials.
Their findings were published in the New England Journal of Medicine (NEJM).
Because there is no established benchmark yet to determine what level of antibodies are needed to protect against the virus, it is unclear whether that two-thirds reduction will render the vaccine ineffective against the variant spreading around the world.
However, UTMB professor and study co-author Pei-Yong Shi said he believes the Pfizer vaccine will likely be protective against the variant.
“We don’t know what the minimum neutralizing number is. We don’t have that cutoff line,” he said, adding that he suspects the immune response observed is likely to be significantly above where it needs to be to provide protection.
That is because in clinical trials, both the Pfizer/BioNTech vaccine and a similar shot from Moderna Inc conferred some protection after a single dose with an antibody response lower than the reduced levels caused by the South African variant in the laboratory study.
Even if the concerning variant significantly reduces effectiveness, the vaccine should still help protect against severe disease and death, he noted. Health experts have said that is the most important factor in keeping stretched healthcare systems from becoming overwhelmed.
More work is needed to understand whether the vaccine works against the South African variant, Shi said, including clinical trials and the development of correlates of protection – the benchmarks to determine what antibody levels are protective.
Pfizer and BioNTech said they were doing similar lab work to understand whether their vaccine is effective against another variant first found in Brazil.
Moderna published a correspondence in NEJM on Wednesday with similar data previously disclosed elsewhere that showed a sixfold drop antibody levels versus the South African variant.
Moderna also said the actual efficacy of its vaccine against the South African variant is yet to be determined. The company has previously said it believes the vaccine will work against the variant.
Wearing a mask — any mask — reduces the risk of infection with the coronavirus, but wearing a more tightly fitted surgical mask, or layering a cloth mask atop a surgical mask, can vastly increase protections to the wearer and others, the Centers for Disease Control and Prevention reported on Wednesday.
New research by the agency shows that transmission of the virus can be reduced by up to 96.5 percent if both an infected individual and an uninfected individual wear tightly fitted surgical masks or a cloth-and-surgical-mask combination.
Dr. Rochelle P. Walensky, director of the C.D.C., announced the findings during Wednesday’s White House coronavirus briefing, and coupled them with a plea for Americans to wear “a well-fitting mask” that has two or more layers. President Biden has challenged Americans to wear masks for the first 100 days of his presidency, and Dr. Walensky said that masks were especially crucial given the concern about new variants circulating.
“With cases hospitalizations and deaths still very high, now is not the time to roll back mask requirements,” she said, adding, “The bottom line is this: masks work and they work when they have a good fit and are worn correctly.”
Virus-related deaths, which resurged sharply in the United States in November and still remain high, appear to be in a steady decline; new virus cases and hospitalizations began to drop last month. But researchers warn that a more contagious virus variant first found in Britain is doubling roughly every 10 days in the United States. The C.D.C. cautioned last month that it could become the dominant variant in the nation by March.
As of Feb. 1, 14 states and the District of Columbia had implemented universal masking mandates; masking is now mandatory on federal property and on domestic and international transportation. But while masks are known to both reduce respiratory droplets and aerosols exhaled by infected wearers and to protect the uninfected wearer, their effectiveness varies widely because of air leaking around the edges of the mask.
“Any mask is better than none,” said Dr. John Brooks, lead author of the new C.D.C. study. “There are substantial and compelling data that wearing a mask reduces spread, and in communities that adopt mask wearing, new infections go down.”
But, he added, the new research shows how to enhance the protection. The agency’s new laboratory experiments are based on the ideas put forth by Linsey Marr, an expert in aerosol transmission at Virginia Tech, and Dr. Monica Gandhi, who studies infectious diseases at the University of California, San Francisco.
One option for reducing transmission is to wear a cloth mask over a surgical mask, the agency said. The alternative is to fit the surgical mask more tightly on the face by “knotting and tucking” — that is, knotting the two strands of the ear loops together where they attach to the edge of the mask, then folding and flattening the extra fabric at the mask’s edge and tucking it in for a tighter seal.
Dr. Brooks cautioned that the new study was based on laboratory experiments, and it’s unclear how these masking recommendations will perform in the real world (the experiments used three-ply surgical and cloth masks).“But it’s very clear evidence that the more of us who wear masks and the better the mask fits, the more each of us benefit individually.”
Other effective options that improve the fit include using a mask-fitter — a frame contoured to the face — over a mask, or wearing a sleeve of sheer nylon hosiery material around the neck and pulled up over a cloth or surgical mask, the C.D.C. said.
Even as vaccines are being slowly rolled out across the country, the emergence of the new variants, which may respond differently to treatments or dodge the immune system to some degree, has prompted public health officials to emphasize that Americans should continue to take protective measures like masking.
About 6% of the US population has been vaccinated against Covid-19, according to the latest data from the US Centers for Disease Control and Prevention. Close to 20 million people have received at least one dose of the two-dose regimen — which trial data shows can offer partial protection against the virus — and more than 3.8 million people are fully vaccinated.
Studies show that people who recover from Covid-19 are largely immune to the virus for a period of time. About 25 million cases of Covid-19 have been reported to the CDC, representing about another 8% of the population with some protection against Covid-19.
However, the CDC estimates that just a fraction of total Covid-19 cases in the US have actually been reported. The latest estimates show that total cases may have topped 83 million through December. Along with the 5 million or so cases that have been reported in January, about 88 million people — more than a quarter of the US population — may actually be protected from Covid-19 after recovering from infection.
Experts say that people who have already had Covid-19 should still get the vaccine. The immunity you get from contracting Covid-19 does last for a certain amount of time, but the nature of the vaccine should provide longer immunity, according to CNN Chief Medical Correspondent Dr. Sanjay Gupta.
The CNN estimates of current protection against Covid-19 do not account for any potential overlap among individuals who may be counted in both the number of people who have been vaccinated and those who have been infected.
With at least one vaccine dose administered to about 6% of the population and potentially a quarter of the population immune after infection, as many as about 1 in 3 people in the US may currently be at least partially protected against Covid-19.
That said, trial data shows that one dose of vaccine only offers partial coverage. And while some studies found that immunity to Covid-19 may last years after infection, others have found it may wane after just five months.
On Tuesday, President Joe Biden announced a boost to vaccine supply allocated to states and promised to have enough doses to vaccinate at least 300 million people by late summer or early fall.
Scientists are settling on a road map that can help critical sectors of the economy safely conduct business, from meatpacking plants to financial services, despite the pandemic’s continued spread.
After nearly a year of study, the lessons include: Mask-wearing, worker pods and good air flow are much more important than surface cleaning, temperature checks and plexiglass barriers in places like offices and restaurants. And more public-health experts now advocate wide use of cheap, rapid tests to detect cases quickly, in part because many scientists now think more than 50% of infections are transmitted by people without symptoms.
The playbook comes after months of investigations on how the coronavirus spreads and affects the body. Scientists combined that with knowledge gained from years of experience managing occupational-health hazards in high-risk workplaces, such as factories and chemical plants, where tiny airborne pollutants can build up and cause harm. They say different types of workplaces—taking into account the types of interactions workers have—need slightly different protocols.
The safety measures have taken on new urgency in recent weeks as new infections, hospitalizations and deaths rise across the U.S. and Europe, and potentially more-transmissible variants of the virus spread around the globe. This phase of the pandemic is prompting a new wave of stay-at-home orders, closures and travel restrictions, important first steps to curbing contagion. Infection-prevention specialists say known strategies for stemming spread should continue to work against the new variants, but that increased adherence is even more important.
Vaccines are rolling out, but slowly, and access will be limited mostly to high-priority groups for some time.
“We have to still deal with ‘the right now.’ We’ve zeroed in on this set of controls that we know work,” said
Joseph Allen,
director of the Healthy Buildings Program at the Harvard T.H. Chan School of Public Health.
Over the past year, the lack of consistent and cohesive messaging among scientists and lawmakers has seeded confusion over what makes up risky behavior, what activities should be avoided and why. That is beginning to change as consensus builds and scientists better understand the virus.
In the U.S., scientists at first advised people against wearing masks, in part because of shortages, while the idea of stay-at-home orders received severe pushback from some lawmakers. Early in the pandemic, testing was limited to people with symptoms, also partly due to shortages. That advice has shifted, but a year later, sufficient testing remains a critical issue.
London’s Regent Street was nearly empty last week.
Photo:
May James/SOPA Images /Zuma Press
Countries such as New Zealand and others in Asia adhered to a combination of basic mitigation strategies from the start—particularly masking, large-scale testing and lockdowns that broke transmission chains. They have tended to fare better than those that didn’t.
In one of his first moves, President
Biden
signed executive orders to require masks be worn on federal property and at airports and other transportation hubs. The administration said it is focusing on increasing the availability of vaccines, and also stressed the importance of widely available testing, which still lags in low-income and minority communities.
The current scientific playbook follows from two of the biggest research insights since the start of the pandemic. First, individuals who aren’t showing symptoms can transmit the virus. Infectious-disease experts worry most about this silent spread and say it is the reason the pandemic has been so hard to contain. While visibly sick people can pass on the virus, data cited by the Centers for Disease Control and Prevention estimate that 40% to 45% of those infected never develop symptoms at all. With the new viral variants that can transmit more readily, the potential for silent spread is even higher, infectious-disease experts said.
Secondly, researchers now know that tiny airborne particles known as aerosols play a role in the spread of Covid-19. These can linger in the air and travel beyond 6 feet.
An early hallmark of the pandemic response focused on the risk of transmission through large respiratory droplets that typically travel a few feet and then fall to the ground. Businesses rushed to buy plexiglass barriers, creating shortages.
The barriers can be good at preventing larger virus-containing droplets from landing on and infecting healthy individuals. They may offer some protection in shielding workers who have brief face-to-face interactions with many people throughout the workday, such as cashiers and receptionists, some occupational-health experts said.
Yet in settings like offices, restaurants or gyms, the role of the barriers is murkier, because activities like talking loudly and breathing deeply create aerosols that can waft on air currents and get around shields.
A Los Angeles Apparel employee added plexiglass to sewing stations in July.
Photo:
Sarah Reingewirtz/Orange County Register/Zuma Press
Outdoor diners at Eat At Joe’s restaurant in Redondo Beach, Calif., in December.
Photo:
patrick t. fallon/Agence France-Presse/Getty Images
A gym in Milan in October.
Photo:
DANIEL DAL ZENNARO/EPA-EFE/Shutterstock
Also, installing such barriers could affect airflow throughout the space, environmental-health experts said. It is possible they could limit proper ventilation, making things worse, they said.
“There seems to be an assumption that particles are going to get stopped by the barriers, which is simply not true,” said
Lisa Brosseau,
an industrial hygienist and research consultant for the University of Minnesota’s Center for Infectious Disease Research and Policy. Airborne particles ferrying the virus “really distribute all over the place.”
The emphasis on intense surface cleaning has diminished as scientists have come to understand that indirect transmission through contaminated surfaces doesn’t play as critical a role in the spread of Covid-19 as they thought in the early days of the pandemic. In September, the CDC published sanitation guidelines for offices, workplaces, homes and schools that said that, for most surfaces, normal, routine cleaning should suffice, and that frequently touched objects, such as light switches and doorknobs, should be cleaned and disinfected.
“Sanitation is important in general always,” said
Deborah Roy,
president of the American Society of Safety Professionals. “The idea is we went overboard at the beginning because of the amount of unknowns. Now, we’re in a situation where we have more information.”
Temperature checks have become less popular among some employers because scientists now know that not all Covid-19 patients get fevers. One large study published online in November in the New England Journal of Medicine showed only 13% of Covid-19 patients reported a fever during the course of their illness.
Scientists now understand that brief encounters with an infected person can lead to spread, according to an October case study—an advance from earlier, when the rule of thumb was to avoid close contact for 15 consecutive minutes or longer. The report urged people to consider not just time and proximity in defining close contact with a Covid case, but also ventilation, crowding and a person’s likelihood of generating aerosols. Following the report, the CDC changed its definition of close contact to a total of 15 minutes or more over a 24-hour period.
A flight attendant showed an air filter on LATAM airlines in Bogota in August.
Photo:
juan barreto/Agence France-Presse/Getty Images
Fresh air and effective filters indoors are important because they can remove virus particles before they have time to infect.
Masks offer a similar benefit, by lowering the amount of particles that infected individuals emit. Some scientists say there could be a benefit to doubling up on masks, as a second layer may improve both filtration and fit, so long as the masks are worn correctly.
A study published in October found that in countries where mask wearing was the norm or where governments put in place mask mandates, coronavirus mortality rates grew much more slowly than in countries without such measures. This fall, the CDC said that masks also offer some personal protection by reducing a wearer’s exposure to infected particles.
As the weather gets colder and people head indoors, the risk of catching Covid-19 is rising. WSJ explains why air ventilation and filtration are one of our biggest defenses against the coronavirus this winter. Illustration: Nick Collingwood/WSJ
The combination of airborne particles and personal interactions, even among people who don’t feel ill, can turn wedding receptions, plane rides and choir practices into superspreading, potentially deadly events.
“For Covid, those two factors—asymptomatic spread and aerosolization—is what made mask-wearing so essential,” said
Megan Ranney,
emergency physician and assistant dean at Brown University.
Lessons can be gleaned from an outbreak at a Canadian spin studio last fall. The operators of the SPINCO studio in Hamilton, Ontario, had many public-health measures in place, including limiting the number of bikes in each class and screening staff and attendees with a questionnaire about topics including symptoms and travel. Rooms were sanitized within 30 minutes of a completed class, and towels were laundered, according to a statement provided last fall by
Elizabeth Richardson,
medical officer of health for the city of Hamilton.
Masks were also required before and after workout classes, Dr. Richardson said.
In total, 54 people who attended workouts over a span of several classes became infected. Another 31 cases were tied to the outbreak after spin-class attendees who contracted the virus then passed it on. The spin studio temporarily shut down following the outbreak and later reopened. It is currently not offering classes due to local regulations that mandated the closure of all gyms and fitness centers amid rising Covid-19 cases in the area.
In a November statement following the outbreak,
Michelle August,
founder of SPINCO, said that the company has “always put safety first and [has] exceeded all recommended guidelines from public health throughout” the pandemic. She said SPINCO has also strengthened and heightened its Covid-19 mitigation measures. SPINCO’s website currently says face masks are mandated throughout workouts in the company’s Hamilton location.
It also says that SPINCO is installing air purifiers in all of its studios that filter air in the rooms every 17 to 21 minutes. Airborne transmission experts recommend that building managers pump in clean, fresh air between three to six times an hour and that they install filters that are proven to effectively trap and remove a substantial number of virus-carrying particles.
To film a stage play of “A Christmas Carol” in November, the Guthrie Theater in Minneapolis upgraded its air filters and increased the rate at which the ventilation system pumps in outside air, said
Brooke Hajinian,
the Guthrie’s general manager. Management staggered arrival times, and a compliance officer made sure everyone socially distanced, wore their masks properly and washed their hands.
The theater divided staff into pods depending on how close they must get to the lone actor on stage, who portrayed Charles Dickens and didn’t wear a mask while performing, according to Ms. Hajinian. Those working nearest the stage underwent testing three times a week and wore N95 masks at all times, she said, while cleaning and security crews, who didn’t interact with the stage crews, wore cloth masks and didn’t undergo testing.
Actor Nathaniel Fuller performed in ‘A Christmas Carol’ at the Guthrie Theater in Minneapolis.
Photo:
Kaitlin Schlick
Ms. Hajinian said she monitored the staff’s testing results and symptoms. “Any symptom is not a failure of this plan,” she said. Catching a case “and isolating it—that’s what success looks like for us,” she said. There were no cases, she said.
Scientists say multilayered safety efforts are needed because no single prevention method is 100% effective.
One of the largest studies of asymptomatic transmission to date showed that frequent testing was essential in identifying infections among a group of nearly 2,000 Marine recruits required to socially distance and wear masks except while eating and sleeping.
The study looked at cases identified with lab-based tests that search out and amplify the genetic material of the virus, but those tests aren’t as easily scaled as so-called rapid antigen tests, which search for viral proteins.
Results from lab-based tests can sometimes take days, while results from rapid tests are usually available in less than an hour. As a result, some epidemiologists have been advocating for widespread use of antigen tests to prevent outbreaks, because they are cheaper and don’t require high-tech laboratory equipment to run, meaning they can be deployed in a broader range of settings.
The shift toward using frequent, inexpensive and rapid tests on the same people multiple times a week to screen entire populations—instead of one-time tests on individuals who have symptoms—will be important to efficiently break transmission chains, epidemiologists said.
“Unless we’re doing really broad, frequent screening of the people at large, we’re completely missing the vast majority” of infections, said
Michael Mina,
an assistant professor of epidemiology at the Harvard T.H. Chan School of Public Health. “We have to change how we’re doing this.”
A Covid-19 testing site at the Alemany Farmers Market in San Francisco in November.
Photo:
David Paul Morris/Bloomberg News
While rapid tests tend to be less sensitive than lab-based tests, Dr. Mina said the data suggest they have high sensitivity when people are most likely to be infectious.
Other infectious-disease experts have touted contact tracing to identify and bust clusters of infection. But they say the strategy works best when cases aren’t surging, as they are now. When transmission rates are too high, limiting gatherings, travel and crowding are more effective at denting spread, said
Abraar Karan,
a global-health physician at Brigham and Women’s Hospital and Harvard Medical School.
In places without big surges, a high-tech approach is becoming increasingly useful: genetic epidemiology, or tracking tiny changes in viral genomes to map out transmission chains. As the coronavirus replicates and moves from person to person, its genes change slightly. Sometimes, those tiny changes are unusual, and they can be particularly useful in mapping transmission events, according to
Justin O’Grady,
an infectious disease expert at the Quadram Institute in the U.K.
By sifting through the differences among more than 1,000 viral genomes, Dr. O’Grady and his collaborators found that a particular viral variant was moving through multiple nursing homes in the U.K., among patients and staff, but not among the wider community. The unpublished data suggested that transmission was facilitated by the movement of staff from one facility to another, Dr. O’Grady said. The team relayed the findings to government authorities and advised them to restrict staff moving among facilities during the pandemic.
“Sometimes genomic epidemiology is able to find hidden transmission links that traditional epidemiology would struggle to find,” Dr. O’Grady said. “We can’t stop transmission, but when we find a superspreader event…we can bring in the right prevention methods to stop it from spreading further.”
A London ad urged safety measures last week.
Photo:
Dinendra Haria/London News Pictures /Zuma Press
—Betsy McKay contributed to this article.
Write to Daniela Hernandez at daniela.hernandez@wsj.com, Sarah Toy at sarah.toy@wsj.com and Caitlin McCabe at caitlin.mccabe@wsj.com
