What Would an Epidemiologist Do?

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AS CORONAVIRUS cases continued to spike in some 20 states, infectious disease specialist Dr. Anthony Fauci said last week, “We’re still in a first wave.”  For people continuing to search for the ways to protect themselves, the answers remain the same: Wear a mask, wash hands and nearby surfaces and keep a physical distance—preferably outdoors.

For specific advice, a survey asking epidemiologists about personal safety choices was one of four most-read New York Times stories in the week that ended June 14 —despite many flaws, such as the participation of just over 500 among the more than 6,000 epidemiologists invited, leaving room for self-selection bias in the conclusions.

Among those epidemiologists who declined to participate, some criticized the survey design use of multiple-choice questions to select the amount of wait time before beginning each activity: “this summer,” “3 to 12 months,” “one year-plus” or “never again.” Others faulted the presentation of results, which lumped responses together without accounting for different experiences, notably those dependent on geographic location.

While some survey questions received fewer than 300 responses, the one addressing travel by airplane received 512, with the largest group, 44%, opting to wait 3 to 12 months, and the next largest, 37%, longer than a year.

Many physicians contend that HEPA (high-efficiency particulate) air filters on airplanes offer more than adequate protection. On the other hand, “passengers can still breathe in tiny floating droplets from a coughing passenger seated nearby—before the air carrying those droplets can be vented out of the cabin and filtered,” according to the Washington Post.

In 2003, during the outbreak of Severe Acute Respiratory Syndrome (SARS) caused by another coronavirus, 22 of the passengers who traveled with a feverish man —who later died of atypical pneumonia—subsequently received a diagnosis of SARS, including two who sat seven rows in front of him.

Other survey questions that both received more than 500 responses, with the majority of responses falling into the category of waiting 3 to 12 months, included eating at a dine-in restaurant, 56%; attending a small dinner party, 46%; and hiking or picnicking outdoors with friends, 41%.

Finally, responses with majority percentages falling into the category of more than one year included “attending a sporting event, concert or play,” 64% (489 responses); “stop routinely wearing a face covering,” 52% (513); and “attending a wedding or funeral, 42% (501).”

Public restrooms are one issue that didn’t show up in the NYT survey. According to the Boston Globe, however, “nearly every person the Globe spoke to thought he or she was alone in their ‘bathroom obsession, but in fact nearly half of people informally surveyed by the American Restroom Association, at the Globe’s request, said they are limiting trips” due to coronavirus concerns.

In response to these concerns, restaurants like McDonalds require sanitizing restrooms at least every 30 minutes; and restrooms at highway rest stops are reportedly extremely clean. But while the general advice about toilets includes putting the top down while flushing to keep aerosolized particles inside, public toilets rarely have tops, making the mask-on strategy especially important for using these.

UV-C ultraviolet light may offer additional cleaning possibilities for public places, and newer devices on the market tout protection for personal devices like phones and more. But UV-C has not yet proved to kill this coronavirus. Other drawbacks include the failure of UV-C light to work on rough surfaces or get into nooks and crannies—for example, on buttons or cell phone cases, explains New York University pathology professor Philip Tierno.

In addition, for UV-C to kill microorganisms, surfaces must be free of dust, skin cells and skin oils. Finally, because UV-C rays do not produce heat or bright light, people might fail to take the precautions needed to protect eyes from damage and skin from burns.

Another counter measure in use without sufficient caution: cleansers and disinfectants. Calls to poison centers concerning exposure to cleaning products and disinfectants increased more than 20% from January, just before Covid-19 began to spread, through March—compared with the same period last year.

People reported washing vegetables and fruit with bleach, misting their bodies with disinfectant spray and gargling with cleaning products. Used correctly, however, these products help prevent the spread of aerosolized particles, which may remain on surfaces for days—although respiratory droplets are the much more common mode of virus transmission, for which the best protection is wearing masks.

A new reason to worry about aerosol particles while they remain airborne is the possibility that these “could enable the virus to penetrate deeper into the lungs and trigger a more severe infection,” according to microbiologist  Raymond Tellier at McGill University.

Despite intense focus on the virus itself—modes of transmission, mutations and dosages—the most critical factor is the person getting infected, the “host,” according to the Post. National Institutes of Health Director Francis Collins suggested that some people’s immune systems might be better able to protect against this new invader because of previous exposure to genetically related coronaviruses.

Investigations into whether increasing vitamin D—via supplements or sunshine exposure—might help protect against the coronavirus led to the conclusion that “people with lower vitamin D have a higher risk of Covid infection, but it looks like this is explained by other risk factors and not by the vitamin itself,” according to Claire Hastie, public health researcher at the University of Glasgow.

That said, daily vitamin D intake via food or supplements should be around 800 I.U. for those 71 and older, and 600 for those younger—and adding 1,000 to 2,000 I.U each day via supplements could help avoid a deficiency, says Harvard Medical School professor and preventive medicine specialist JoAnn Manson. Manson cautioned against taking higher doses.

Another suggestion is that an individual’s genetic susceptibility could create greater risk for inflammation or the other problems associated with severe Covid-19.  In one study, patients with Type A blood had a 50% higher risk of needing a ventilator—possibly because Type A blood is associated with small blood clots, found in many of the most serious cases. Type O blood seemed to have a partial protective effect. When genetic links are clearer, a blood test early in the course of the disease could help determine which patients are most vulnerable.

What is better known is the higher risk of severity among those over 60 due to immunosenescence, the diminishing of immune response with age; those with preexisting conditions of diabetes and hypertension; and those considered obese. In the NYU Langone hospital system, obesity was the number one risk factor in those under 60, according to hospital epidemiologist Jennifer Lighter.

Based on age, gender and pre-existing conditions, the United Kingdom has created two categories of risk for reopening, with those at low risk advised to social distance and those at higher risk, to “shield:” stay inside as much as possible and avoid contact with others.

Among those looking at risk groups in the U.S., Lighter points to the clear advantages of being young and healthy: among 238 sailors aboard the aircraft carrier USS Theodore Roosevelt who tested positive for the virus after an outbreak on the ship, only two required hospitalization, according to the CDC. And one out of 5 reported no symptoms at all.

For everyone else, the advice is to stay healthy and fit, says Carl Heneghan, director of the Center for Evidence-Based Medicine at Oxford University. “If you’ve got diabetes, you’ve got to lose weight and moderate that. If you do all those things, your risk of dying is small, or very small.”

—Mary Carpenter

Well-Being Editor Mary Carpenter continues to update us on Covid-19. To read more of her posts, click here.