Previous Vaccines, Masks May Influence COVID-19 Spread

Carolyn Crist

August 14, 2020

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

Prior vaccinations and face masks could be part of the reason why the coronavirus affects different people in different ways, according to CNN.

Researchers are studying why the coronavirus seems to cause more harm to some people than others. Those who have had a variety of vaccines — for the flu, hepatitis and pneumococcus — seem to have a lower risk of getting COVID-19.

"A good analogy is to think of your immune system as being a muscle. The more you exercise that muscle, the strong it will be when you need it," Andrew Badley, MD, an infectious disease specialist at the Mayo Clinic, told CNN.

Although scientists can't say for sure that other vaccines have boosted people's immunity to COVID-19, they think it's possible, the news outlet reported. One team of U.S. researchers has suggested that giving a measles, mumps and rubella booster could prevent severe coronavirus symptoms, and another group found that countries that frequently give the Bacillus Calmette-Guerin vaccine for tuberculosis have had fewer COVID-19 deaths. The vaccine has offered broad protection against other infectious diseases, they said.

Face coverings could also play a role in the severity of disease, researchers told the news outlet. About 40% of people who contract the coronavirus don't show symptoms, according to the CDC, and masks could lower the viral load that leads to severe consequences.

"What the mask does is really reduce the amount of virus that you get in, if you do get infected," Monica Gandhi, MD, an infectious disease specialist at the University of California, San Francisco, told CNN.

"By reducing that … you have a lower dose, you're able to manage it, you're able to have a calm response and you have mild symptoms or no symptoms at all," she said.

As of Thursday morning, the U.S. has reported more than 5.2 million coronavirus cases and 166,000 deaths, according to data from Johns Hopkins University. The current averages are 54,000 new cases and 1,000 new deaths per day.

"We have nothing to celebrate because we're going to 50,000 cases per day," Rochelle Walensky, MD, the chief of infectious diseases at Massachusetts General Hospital, told CNN.

"Even at 18,000 cases per day in mid-May, we were unable to really squelch this," she said.


CNN, "Previous vaccines and masks may hold down Covid-19, some researchers say."

mBio, "Could an Unrelated Live Attenuated Vaccine Serve as a Preventive Measure To Dampen Septic Inflammation Associated with COVID-19 Infection?"

PNAS, "BCG vaccine protection from severe coronavirus disease 2019 (COVID-19)."

CDC, "COVID-19 Pandemic Planning Scenarios."

Johns Hopkins University, "COVID-19 Dashboard."