Masks Worn Amid COVID-19 May Lead To Form Of Immunity
SAN FRANCISCO (KPIX) -- In a newly-penned request sent to vice president Mike Pence, the Infectious Disease Society Association has officially urged the White House to publicly issue a federal directive asking all states to require masks to control the pandemic.
Now, a new report bolsters their request: a theory that mandated face covering may add an additional and very important benefit.
This theory is backed by mounds of evidence: that a national mask mandate will get us through the pandemic quicker, without additional lockdowns -- possibly with some form of immunity as we wait for a safe and effective vaccine.
Masking may turn a very scary disease into a milder infection, which then might provide you and the people around you with some kind of immunity.
"Even if you do get infection, it looks like the evidence is showing us that you're getting less virus and that you're less likely to get sick," said UCSF infectious disease expert Dr. Monica Gandhi. Dr. Gandhi is lead author of the report published in the Journal of General Internal Medicine.
Her research details multiple layers of proof.
It is established that a higher dose of a virus leads to more severe disease. As early as 1938, in a paper published in the American Journal of Hygiene, there was evidence that reduced viral inoculum -- or dose -- leads to less severe disease. In one study involving the flu, human volunteers were given different doses of influenza and found higher doses led to more severe disease.
And with the novel coronavirus, in late February to early March, epidemiologists discovered there is a high amount of virus "shedding" from the mouth and nose, even among those who exhibit no symptoms.
Dr Gandhi told KPIX how a mask, while not perfect, greatly reduces the dose you give or get, resulting in a milder infection or no infection at all. She provided a few examples from the COVID-19 pandemic. The first occurred early in the outbreak.
"We call it the tale of two cruise ships," said Dr. Gandhi
She and her team compared the Diamond Princess in Asia to an expedition cruise in South America.
Both ships were hit hard with a coronavirus outbreak. At first, everyone on board had to stay aboard so the ships became floating petri dishes.
With the report of the first infection, the Diamond Princess did not immediately hand out masks but the expedition cruise did.
The masking made a difference: the vast majority of infected passengers onboard the expedition cruise -- 81 percent -- remained asymptomatic. Dr. Gandhi said to compare that to 18 percent who remained asymptomatic aboard the Diamond Princess where there were no masks.
In addition, Dr. Gandhi and her co-authors reported that, when workers wore masks during an outbreak in an Oregon seafood plant and an Arkansas chicken plant, 95 percent of the workers who were infected remained asymptomatic.
"All this evidence leads us to believe that the mask filters out viral particles. It makes you have less in and you're less likely to get sick," Dr. Gandhi explained.
As of July 22, Dr. Gandhi reported that, among a group of 30,000 tested by a Bay Area technology company called Color, the majority of those who tested positive had mild or no symptoms.
As for those now in the ICU, Dr. Gandhi noted most were essential workers who were not given a mask.
The next question: if you're infected with a smaller dose and have mild symptoms or no symptoms at all, then do you have immunity and for how long would you be protected? So far, no one knows for sure but there's no convincing evidence you can get re-infected, just anecdotal reports.
There is some evidence among infected rhesus macaques that the infection protects the monkeys against any "re-challenge" or new infection. In addition, among COVID-19 patients who have recovered, scientists have found T-cells, which bodes well for longterm immunity.
The goal is not to get infected, even asymptomatically. But Dr. Gandhi notes that the hopeful thing about asymptomatic infection is that it may act like a "poor man's vaccine" and provide some immunity and serve as a bridge until we get a vaccine.
"There's very hopeful data that you can be asymptomatic and still get that immunity ... population level immunity will drive down the spread. It will naturally drive down spread as you're waiting for the vaccine," Dr. Gandhi said.
"It's a wonderful theory. I hope it works," said Dr. William Schaffner, a renowned infectious disease expert at Vanderbilt University Medical Center. He said masks are critical in suppressing this pandemic, even if they are not perfect.
"A little bit of virus that does get through. Their hypothesis is that it gives you a milder infection. So, you get protected on the cheap, as it were, and that may help actually give many people protection," Dr. Schaffner said.
He said the Gandhi report is another good reason to "mask up."
"We should all continue to wear our masks every day as we leave our house," Schaffner cautioned.
Dr. Gandhi said that, when it comes to choosing a mask, it's critical to find one that you'll continue to wear so make sure it's comfortable. An N95 may filter out most particles but most people can't bear to wear them for long periods of time. Not only that, even if you have a face covering that is less than perfect, it's better than not wearing a mask at all because of discomfort.
In addition to wearing a mask, remember to practice good hand hygiene and social distancing.
WEBLINK: Gandhi Report