In 1349, as the Black Death ravaged Europe, a new pandemic-control strategy was adopted in cities across the continent. The protocol was precisely regulated by the experts. Three times a day, for a total of exactly eight hours, hundreds of men known as Flagellants would march in single file through town, wearing caps with a red cross and carrying scourges of knotted ropes studded with nails. “Using these whips,” one witness reported, “they beat and whipped their bare skin until their bodies were bruised and swollen and blood rained down, spattering the walls nearby.”
This specific strategy is no longer in favor among public health officials, but the spirit of the Flagellants lives on. Instead of beatdowns, today’s regulators favor lockdowns, which are less bloody but inflict more social pain. For all the talk about following science, the authorities—and much of the citizenry—can’t resist the primal intuition that a pandemic can be quelled only through public penance. Consider two strategies for dealing with the Covid-19 virus: urge the public to spend time outside in the sun to build up their vitamin D, and to take supplements of the vitamin, repeatedly demonstrated to protect against viral infection; or shut down most businesses, deprive children of classroom education, and order everyone to stay home, a strategy never previously tested and yet to prove effective.
Which strategy would you try first? If you chose the vitamin D, you have no future in the public-health establishment. While a few researchers are touting the vitamin’s potential and advocating government programs to distribute the supplements during the pandemic, the Centers for Disease Control can’t bring itself even to suggest that people take the pills on their own. In its Covid-19 guidelines, the CDC declares that “there are insufficient data to recommend either for or against the use of vitamin D.”
Somehow, though, the “insufficient data” problem disappeared when it came to lockdowns and mask mandates. Before the pandemic, the official expert consensus was against those measures, but the consensus was promptly discarded in the hope that these sacrifices might help. The evidence since then could easily be called insufficient, given the lack of randomized studies and the inconvenient data showing that places with lockdowns didn’t fare any better than the places without strict measures. And given what has emerged about the minuscule rate of transmission in outdoor settings, you could certainly say there’s insufficient evidence to order people to stay inside their homes or to mandate masks outdoors.
But whatever these lockdowns and mandates do or don’t accomplish in stopping viral spread, they definitely enable officials and citizens to demonstrate that they’re taking bold actions against Covid—and the more painful the measures, the more virtuous and heroic they feel. Whenever evidence emerges that the lockdowns are ineffective, the proponents have a ready answer: not enough people are following the rules. Stop sinning! Do your penance!
Going out for a walk or taking a vitamin D pill is just too easy. It entails no pain and provides no glory or power to public-health officials and politicians, so they rarely give this advice despite the evidence that vitamin D helps the immune system against viral infections. It’s not surprising that groups with disproportionately high rates of Covid mortality are also prone to vitamin D deficiency: African-Americans and other minorities, the obese, residents of nursing homes and other elderly people. Levels of vitamin D tend to decline with age, and because the vitamin is synthesized in the body by exposure to sunlight, people tend to have lower levels if they spend less time outdoors or have darker skin that absorbs less ultraviolet radiation from the sun.
As days shorten in the autumn, people’s vitamin D levels tend to decline because of less exposure to the sun, and that’s one explanation for why the flu season starts in October in northern Europe and the United States (whereas flu occurs throughout the year in tropical countries). To strengthen the immune system, researchers have repeatedly studied the effects of taking vitamin D supplements. After analyzing 25 such studies, the authors of a meta-analysis in the BMJ concluded in 2017 that the supplements do indeed help prevent colds, influenza, and other respiratory infections.
Would these supplements protect against Covid? Researchers in Chicago, Indonesia, Israel, and other places have found that people with vitamin D deficiency are disproportionately represented among people infected with Covid and among patients suffering from severe cases. In a randomized clinical trial in Spain, Covid patients who received doses of the vitamin were less likely than the control group to develop severe cases. “I consider it scientifically almost proven that high levels of vitamin D provide protection against severe COVID-19, but even more importantly there appears strong evidence that high vitamin D levels slow markedly virus circulation,” says Mikko Paunio, an epidemiologist and medical adviser in Finland’s Ministry of Social Affairs and Health. He says he has started taking a daily supplement of 4,000 IU.
Tom Frieden, the former CDC director, agrees that the supplements are a good idea, although he suggests a daily dose between 800 and 2,000 I.U. While the case hasn’t been proven, he wrote, vitamin D “may potentially provide some modest protection” against Covid, particularly for the more than 40 percent of Americans who are deficient in the vitamin. “Taking a multivitamin that includes Vitamin D, or a Vitamin D supplement, probably can’t hurt, and it might help.”
The Health Ministry in Israel has been recommending vitamin D against Covid, and Scotland’s National Health Service has been distributing free supplements to people who have shielded indoors during the pandemic. Otherwise, though, governments have paid scant attention to it. When Anthony Fauci was asked about vitamin D during an Instagram conversation with the actress Jennifer Garner, he said that he himself takes a supplement and “would not mind recommending” it to protect again Covid, but at his White House press conferences he prefers to lecture Americans about wearing masks and sacrificing pleasures like family dinners during the holidays.
Those painful measures give at least the illusion that something serious is being done—and even if the measures turn out to be useless, officials can always claim success when the pandemic ebbs, as all pandemics eventually do. During the spring surge, infections in New York were already declining before Governor Andrew Cuomo announced his lockdown, but he has been taking credit ever since for “controlling the virus” thanks to the lockdown’s “enormous sacrifices.” If he’d been leading the Flagellants through the streets of London in 1349, he would have been making the same boast. After all, the Flagellants began their daily floggings at the end of September; just two months later, the bubonic plague subsided. To a leader and a public already convinced that a plague requires penance, that would qualify as following the science.