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Does Alcohol Reduce COVID-19 Vaccine Effectiveness?

woman drinking wine looking at tablet

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Key Takeaways

  • Alcohol consumption has increased during the pandemic.
  • Drinking too much alcohol negatively affects the immune system.
  • Moderate drinking should not interfere with the effectiveness of COVID-19 vaccines.

Whether you are soon getting the SARS CoV-2 (COVID-19) vaccine or you are still trying to avoid contracting the virus, a recently published review of COVID-19 studies recommends avoiding excessive consumption of alcohol as one of the lifestyle interventions to optimize health during the pandemic (and beyond).

Staying as healthy as possible keeps your immune system in top shape, helping to fight off the virus if you get exposed to it or helping to make antibodies against it when you get vaccinated.

But the pandemic has led to an increase in alcohol consumption. According to a study published in the Journal of the American Medical Association, adults consumed 14% more alcohol in 2020 than they did in 2019. And women showed a 41% increase in alcohol consumption from 2019 to 2020. The increase in alcohol consumption during the pandemic has been noted not only in studies of adults in the U.S., but also in studies from Europe and Australia.

“Alcohol consumption has increased at home; people are stressed,” Ilhem Messaoudi, PhD, professor of molecular biology and biochemistry and director of the Center for Virus Research at the University of California, Irvine, tells Verywell. “People should be cautioned about binge drinking; it is pretty traumatic to the immune system. Having a big amount of alcohol at one time really suppresses the immune system,” Messaoudi says. 

Excessive alcohol consumption for women, according to the Centers for Disease Control and Prevention (CDC), is four or more drinks on one occasion or eight or more drinks per week. For men, the CDC defines excessive alcohol consumption as five or more drinks on one occasion or 15 or more drinks per week.

Although excessive alcohol consumption is known to negatively affect the immune system, Messaoudi and her fellow researchers found a surprising effect of moderate alcohol consumption.

“Moderate drinking—one serving of alcohol per day for women and two servings per day for men—can reduce inflammation and enhance the immune response to vaccines,” Messaoudi says. “We did not expect to see that in our study, but both in humans and animals, a little bit of alcohol has benefits. Beyond a very small amount, though, there is a sharp upswing of negative impacts—a J-shaped curve,” she says.

How Alcohol Affects the Immune System

A high alcohol intake, whether long-standing excessive alcohol consumption or binge drinking, has been shown to nearly double the risk of acute respiratory distress syndrome, a complication of COVID-19 that makes breathing difficult. Alcohol’s effects on cell membranes and metabolism are possible explanations for the increased risk, but so is alcohol’s ability to interfere in the maturing of macrophages. Macrophages are white blood cells produced by the immune system that gobble up viruses and other foreign materials they encounter in the body. When macrophages are impaired—such as by excessive alcohol consumption—your body’s first line of defense against infection is affected. 

“Alcohol reprograms the immune cells to create a lot of inflammatory mediators and make a ton of cytokines,” Messaoudi says. “But then the immune system is not able to clear pathogens or activate other immune cells to do their jobs.”

Many people know that chronic alcohol consumption affects the liver, but really big changes occur in the lungs from drinking, says Messaoudi, which has an effect on people with COVID-19. “The cilia in the lungs that are constantly moving to clear gunk don’t beat as well when there is chronic alcohol consumption, so chronic drinkers aren’t able to clear their lungs,” she explains.

If you currently drink alcohol excessively, cut back sooner rather than later. Messaoudi says that even once heavy drinking stops, researchers still see “immunological scars” from that heavy drinking at least three months later.

If you or a loved one are struggling with substance use or addiction, contact the Substance Abuse and Mental Health Services Administration (SAMHSA) National Helpline at 1-800-662-4357 for information on support and treatment facilities in your area. For more mental health resources, see our National Helpline Database.

What This Means For You

“The take-home message is that if you’re truly a moderate drinker, you’re OK,” Messaoudi says. “If you enjoy a glass of wine with dinner and have one the night before you get a COVID-19 vaccination, don’t worry.”

Remember the adage, “Everything in moderation,” be wise about your alcohol intake, and be honest about how much you really consume. 

“And find outlets other than drinking to cope during the pandemic,” Messaoudi says. Her best suggestion? “Go outside and walk."

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.

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