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Do I Need to Worry About the Delta Variant If I'm Vaccinated?

Here's what we know about the effectiveness of vaccines for variants of concerns, notably the delta variant that's now responsible for more than 20% of new U.S. cases.
Sheila Mulrooney Eldred and Pranav Baskar
A sign urges people to get tested for a COVID-19 variant in Blackburn, England. The U.K. is experiencing a surge in the delta variant, which was first identified in India.
A pedestrian walks past an electronic information board displaying a Covid-19 information relating to a 'variant of concern in the area' in Blackburn, north west England on June 16, 2021. - The UK government on Monday announced a four-week delay to the full lifting of coronavirus restrictions in England due to a surge in infections caused by Delta, which first appeared in India.  (Oli Scarff/AFP via Getty Images)

“I’ve been vaccinated. Do I need to worry about variants?”

The answer depends on a few things — including your personal risk tolerance.

But first off, know that your vaccine is quite valuable. The COVID-19 vaccines are expected to be protective against the new virus variants, according to the World Health Organization.

Exactly how much the various vaccines protect against the delta variant — the newest form of the virus that the Centers for Disease Control and Prevention has dubbed a “variant of concern” — is still somewhat of a guessing game. But if you’re fully vaccinated (two weeks after your second dose) the odds are highly favorable that you won’t get a breakthrough COVID-19 infection, and even better that if you are one of the unfortunate few, you won’t get a severe case.

“At least for those vaccines approved in Europe and North America, in the case of the variants, these seem to be effective in preventing severe disease, hospitalization and death,” says Dr. Jerome Kim, director general of the International Vaccine Institute.

The alpha variant, first identified in the U.K., is around 50% more transmissible than the original form of the virus. The Pfizer vaccine was found to be 90% effective against the most severe forms of infection (i.e., those resulting in hospitalization or death) caused by this variant. That study also showed high protection against the beta variant, first spotted in South Africa.

A study from Public Health England, an agency of the Department of Health and Social Care in the U.K., found that AstraZeneca also showed a high level of effectiveness against alpha, with an 86% reduction of hospitalizations. The study has not yet been published.

The delta variant is expected to overtake the alpha variant as the main form of the virus in the United States. More than 20% of new cases in the U.S. are already due to the delta variant.

Since the delta variant is even more transmissible — about 60% higher than alpha — that’s what people in the U.S. will be at highest risk of soon. It’s part of the reason the CDC upgraded delta from a variant of interest to a variant of concern.

Experts are also concerned because therapies such as monoclonal antibodies and convalescent serum don’t seem to work as well against this variant, says Dr. Jill Weatherhead, assistant professor of adult and pediatric infectious diseases at Baylor College of Medicine.

As for the vaccines, one study of the delta variant in Scotland from the University of Edinburgh found that while the variant was associated with a doubling in the risk of hospitalization in those infected in the region, the Pfizer and AstraZeneca vaccines offered a 79% and 60% protection, respectively, against infection two weeks after the second dose. And a study from Public Health England showed that two doses of the Pfizer vaccine were 88% effective against symptomatic disease from the delta variant.

As for other vaccines, David Montefiori, director of the Laboratory for AIDS Vaccine Research and Development at Duke University Medical Center, is optimistic. Based on research he has conducted that has not yet been published, including the Moderna vaccine, he says that “delta does not look like it will be much of a threat to vaccines.”

And Weatherhead has this to say about Johnson & Johnson’s effectiveness for the delta variant: “We just don’t have the data, but that doesn’t mean it’s not efficacious. We know it works against [other variants]. We’re going to have breakthrough infections, but the vaccines really prevent severe disease and death.”

Just keep in mind that vaccines aren’t effective the second you get them, she adds.

“The problem is you’re really not protected until you’ve gotten both doses of the vaccines and you’ve waited two weeks afterward,” she says. “So you’re still vulnerable in between. That’s why it’s so important to get vaccinated now, before [delta] becomes the dominant variant circulating.”

Think about the vaccine as a really good raincoat, suggests Dr. Leana Wen, an emergency physician and public health professor at George Washington University. “If it’s drizzling out, you’re not going to get wet, and even if it’s raining hard, you probably won’t get wet. But if there’s a hurricane or a thunderstorm, there’s a chance you’ll get wet.”

In that case, people who really don’t want to get wet might want an additional layer of protection. Other people may not mind getting damp.

Both of those are reasonable conclusions, Wen says. If the delta — or “delta plus,” an even newer mutation just discovered in India — turns out to be a thunderstorm in your area, some vaccinated people may want to rely on the same precautions we’ve adopted throughout the pandemic: masking up, physical distancing when you’re with unvaccinated people and getting tested when traveling upon arrival and departure to make sure you aren’t carrying any variants into or out of your destination.

Just like stormy weather, outbreaks of COVID-19 due to the delta variant will likely be localized. But unlike a weather forecast, it’s easy to predict where they’ll happen: wherever there are high rates of unvaccinated people, Dr. Anthony Fauci of the National Institutes of Health has said.

Sheila Mulrooney Eldred is a freelance health journalist in Minneapolis. She’s written about COVID-19 for many publications, including Medscape, Kaiser Health News, Science News for Students and The Washington Post. More at sheilaeldred.pressfolios.com. On Twitter: @milepostmedia.

Pranav Baskar is a freelance journalist who regularly answers coronavirus FAQs for NPR.

Each week, NPR’s Goats and Soda answers frequently asked questions about life during the coronavirus crisis. If you have a question you’d like us to consider for a future post, email them at goatsandsoda@npr.org with the subject line: “Weekly Coronavirus Questions.” See an archive of their FAQs here.

Copyright 2021 NPR. To see more, visit https://www.npr.org.

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