AMONG CAUTIONARY tales about the value of testing for the coronavirus comes the recent one of sailors on a fishing boat who received both virus and antibody testing before embarking — after which one sailor became so ill he required hospitalization, and 103 more became infected.
Headlines for the story touted the sparing of three sailors who had tested positive for coronavirus antibodies, indicating the good news that coronavirus antibodies can be protective. On the other hand, six sailors had originally received positive antibody results, but on retesting three were proven to be false positives.
Meanwhile, some countries, notably in Latin America, are paying serious attention to public health issues linked to the risk of serious illness caused by coronavirus infection—the so-called lifestyle-related diseases like obesity, diabetes and heart disease—by passing revolutionary anti-junk food laws.
Around the U.S., the “new velvet rope,” offered by medical concierge services at swank parties as well as by event and festival organizers, is private rapid testing; participants are admitted only after their tests come back negative. Rapid-result tests are available at locations around the country, but some involve waits of six hours or more in line or limited supplies that require arriving hours ahead of the dawn opening. Elsewhere people wait 7 to 14 days for test results.
As evident in the case of the sailors, though, it can take the coronavirus more than a week—and sometimes two—to show up in virus tests, making negative results far from definitive. “You can’t go to a house party the week before you see Grandma,” Demetre Daskalakis, New York City’s deputy commissioner of disease control told the New York Times— the reason the two-week quarantine is the preferred option.
Among the nearly half of U.S. states that require testing and/or quarantine for visitors from high-risk locations, New York imposes a two-week quarantine regardless of test results for visitors from high-risk states—those with a seven-day rolling average of positive cases exceeding 10 per 100,000 residents, or positive results in more than 10% of tests.
Maryland and Virginia have appeared on New York’s “restricted” list of more than 30 states for most of the summer, while D.C. has been on and off, and as of the end of last week was back on again.
For everyone, the mask remains essential protection, but must be removed immediately if wet. Because viruses thrive in wet, warm material, anyone removing a wet mask should touch only the ties or elastic bands—not the material or the face—and afterwards wash everything.
Recent reports on a North Carolina study suggested that some masks, notably gaiters, were ineffective or worse—while in fact the research had focused only on creating measurements for mask effectiveness and had assessed just one person wearing a gaiter—an inconclusive “N-of-one.”
What determines the success of any mask is fabric and fit, according to Virginia Tech professor Linsey Marr, who specializes in aerosols—and whose children wear gaiters. Masks with more than one layer of fabric —including inserts of material like Kleenex—do better than those with just one layer.
The WHO recommends cloth masks of three layers, of which the innermost layer should be wicking material such as soft cotton¯and the outermost layer, a fabric with some water resistance.
Every choice of mask requires compromise on one or more of the variables—fit, breathability, ease in taking on and off. While offering a list of good options, Wirecutter points out that “the best cloth face mask is the one you will wear (and not fuss with).”
Until a vaccine becomes available, the focus remains on antibodies and herd immunity. For this coronavirus, experts have begun to recalculate the percent of people with antibodies required to achieve herd immunity—meaning enough protected people to halt the virus’s spread among the population—down from 70% to 50% or lower.
Previously the target statistic was an R0—the reproductive number for the virus—of one, meaning that each infected person spreads it to only one additional individual. But that “doesn’t happen in real life,” Yale Global Health Institute Director Saad Omer told the New York Times—pointing to wide differences in density and demographics even among nearby locales.
Looking instead at locations, ranging from counties to neighborhoods, and comparing variables such as average age and income levels has turned up extreme differences in the numbers of people with antibodies—or example, 68% of those tested in Corona, Queens, compared with only 13% in more affluent Cobble Hill, Brooklyn.
Even among those who question the degree of protection created by antibodies, many agree that subpar levels of “herd immunity” might help residents in future waves of infection because “the same level of behavior change will have more effect on the disease now than it did four months ago,” according to Australian mathematician Joe Miller.
In Mexico, new anti-junk food laws that prohibit the sale of sugar-sweetened beverages and highly processed foods to those under 18 years old are “a huge win for public health,” according to Yale public health professor Rafael Perez-Escamilla. Another Mexican law taking effect in October requires black stop signs on packages of foods that are high in saturated fats, added sugar and sodium, and calories, which cannot be sold in schools.
“The pandemic has created an explosion of awareness about why Mexicans are so vulnerable to certain diseases,” writes Laura Reilley in the Washington Post—with 73% of Mexicans considered overweight and 34% “morbidly obese,” compared with the U.S. in 2017-2018: 42.4% obese and 9.2% “severely obese.”
The epidemic of lifestyle-related diseases and the coronavirus pandemic are “harmfully synergistic,” according to Dariush Mozaffarian, dean of the Friedman School of Nutrition Science and Policy at Tufts University. Ultra-processed foods —low in nutrients and high in calories, but also less expensive and more shelf-stable—have increased in variety and popularity during the pandemic.
One Mexican official described sugary drinks as “bottled poison.” Along with washing hands and wearing masks, says Mozaffarian, improving metabolic health “should be the third leg of the stool.”
Well-Being Editor Mary Carpenter is on a mission to keep us updated on Covid-19. To read more of her posts, click here.