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Coronavirus FAQs: How worrisome is the new variant? How long do boosters last?

A booster vaccine is administered on the Indonesian resort island of Bali.
Sonny Tumbelaka
AFP via Getty Images
A booster vaccine is administered on the Indonesian resort island of Bali.

We regularly answer frequently asked questions about the coronavirus. If you have a question you'd like us to consider for a future post, email us at with the subject line: "Weekly Coronavirus Questions." See an archive of our FAQs here.

I've heard there is yet another new variant of SARS-CoV-2. Say it ain't so!

Yes, it is so. Viruses mutate, new variants emerge. That's happened a number of times with SARS-CoV-2 since the start of the pandemic in 2020. And it's happening again. In mid-August, the Centers for Disease Control and Prevention announced: "A new variant of SARS-CoV-2 called BA.2.86 was detected in samples from people in Denmark and Israel. At least two cases have been identified in the United States. This variant is notable because it has multiple genetic differences from previous versions of SARS-CoV-2."

In fact there are 35 mutations on the spike protein compared to currently circulating variants. That's as big of a difference as there was between the original virus and the omicron variant identified in November 2021.

The spike protein is what the virus uses to enter our cells. Those mutations could potentially help the virus evade the protection provided by COVID vaccinations and prior infections, says Katelyn Jetelina, an epidemiologist and scientific consultant to the CDC, who writes the "Your Local Epidemiologist" blog.

The CDC and the World Health Organization are taking a closer look.

There's not yet enough data to assess the potential of this variant to cause a wave. But the CDC said on Wednesday that, "based on what [it] knows now, existing tests used to detect and medications used to treat COVID-19 appear to be effective" for the variant.

The CDC also believes that BA.2.86 may be more capable of causing infection in people who have previously had COVID-19 or who have received COVID-19 vaccines because the mutations on the spike protein could allow it to evade our immune systems despite prior vaccinations and having had COVID-19. Scientists are evaluating the effectiveness of the new booster expected to be approved by mid September.

And companies that make antigen tests, vaccines and treatments are testing them to see if they are effective on the variant.

If the conclusion is that this variant poses a significant risk of triggering waves of cases due to its mutations, it will get it own name. That name, next in the Greek alphabet for COVID variants, would be pi.

I have a 66-year-old friend who's never stopped wearing a mask and still refuses to go to restaurants, movies or even socialize indoors. He has had the latest booster. Are these extreme precautions still warranted at this stage?

"It's complicated," says Dr. Waleed Javaid, epidemiologist and director of Infection Prevention and Control at Mount Sinai Downtown in New York City. "Some people refused to mask, and others refuse to unmask. Part of it is knowing your risks, like if you are traveling in a crowded space."

Javaid says we need to to be empathetic to the needs of others. "We don't know other peoples' risks. Some people may have serious illnesses, immunocompromising conditions, cancers, or transplants — and not share this information with their friends or loved ones."

Andrew Pekosz, a professor of molecular microbiology and immunology at the Johns Hopkins Center for Global Health, says "it's still very, very clear that the hospitalizations and deaths from COVID — currently on the rise — are being driven by certain portions of the population: those over the age of 65, those with underlying medical conditions, individuals on cancer treatment, solid organ transplant recipients and people who are immunocompromised. "In my opinion, if you are in those groups that should more than justify taking a few extra precautions if you want to minimize your risk," he says. "And I think we as a society needs to be a little bit more accepting of those individuals who feel the need to take those steps to protect themselves."

As for case counts, the end of the public health emergency for COVID means many data points on cases are no longer collected. But in the U.S., emergency room visits are still tallied and are rising. U.S. hospitalizations are still reported as well and have been increasing steadily since July, based on CDC data. For the week ending Aug. 12, there were 12,613 new hospitalizations for the virus, up from 10,370 the previous week.

How long will it take for the new booster, coming in the fall, to confer protection? A week? 10 days?

First, news alert: A meeting of the CDC's Advisory Committee on Immunization Practices has been set for September 12 to discuss the updated COVID-19 booster, likely to be followed by the CDC director adopting their recommendation very soon after and making recommendations on who should get the updated shot. Pharmacies and doctors offices are already gearing up to give the shot.

Now back to the immunity you can expect. "It takes up to two weeks for you to have the best protection [from a vaccine]," says Dr. Javaid. Andrew Pekosz says for COVID the vaccines may even work a bit faster because of prior immunity people have from vaccines and from having had the virus. "Within ten days you would detect increases in your immunity and by two weeks you should be at pretty good levels that would be protecting you from a COVID-19 infection and particularly severe COVID-19," Pekosz says.

When does protection of COVID vaccines and boosters wane?

"We don't have that long-term data available yet," says Dr. Javaid. "There are multiple factors involved. There are patient factors, illnesses, immunocompromising conditions and the ability to mount immune response depending on medications — like steroids — that suppress the immune system. There are also viral factors, like if the virus mutates enough to evade our immune system."

In general, says Javaid, being vaccinated will provide some degree of protection against infection that can last for months or even years because of the body's immune memory. This means vaccinated individuals will likely have milder symptoms than unvaccinated. And so far, Javaid says, the vaccines have held up well against severe disease.

There are three vaccines this fall — the flu vaccine, the expected fall COVID booster and the RSV vaccine. Can I get them all at once?

You can get the flu shot and fall booster together without any interference of the effectiveness of either, says Matthew Frieman, research professor of microbiology and immunology at the University of Maryland School of Medicine. "In fact," says Frieman, "vaccines that would combine the two are in clinical trials."

Dr. Javaid points out that children get vaccines that combine protection — like one for mumps, measles and rubella (German measles) with no problem.

The CDC gives the thumbs up to getting the flu and COVID vaccines together as well and says you can even get them in the same arm, though getting each in a different arm can help reduce short-term pain that can come with getting a vaccination.

As for timing ... The new boosters aren't here yet. October is considered the best month to get a flu shot since protection can wane over the flu season, which ends in May or June. So assuming that the new booster is out by then, you could go for a two-fer.

Then there are new vaccines, just recently approved, for respiratory syncytial virus (RSV), which is also a fall virus and which is most dangerous for very young kids and older adults. A vaccine is recommended for people 60+ and is available now, and another was just approvedfor pregnant women to provide protection for their babies from RSV right from birth. There's also a treatment for infants that works like a vaccine to protect them.

But there isn't yet data available on whether people over 60 can take the RSV vaccine simultaneously with the COVID and flu vaccines. You may want to consult with your doctor about timing for the RSV vaccine if you are in a risk group, suggests the immunologist Pekosz.

I'm over 65. Does that impact immunity from the booster?

In older adults the body may not be as aggressive in making antibodies as it in younger years, says Dr. Javaid. "This is why it's a good idea to ask your doctor if the CDC recommends more frequent boosting for your age or for individuals in certain risk groups."

Pekosz adds that for your average over-65er, "the immune response from the vaccine should last from four to six months in terms of protecting from severe disease."

And everyone should be considering the updated booster when it's available, says Pekosz, "because the variants that are circulating now are very different from what was in the last vaccine for COVID-19."

The CDC advises that people exposed to someone who has tested positive for COVID wear a mask for at least 10 days and people who test positive themselves wear a mask for at least 5 days. A reader asks if 5 days is enough for someone who is infected?

Dr. Javaid says that if you are exposed to COVID-19 and don't develop symptoms right away, it's good to stay masked for the CDC's recommended time because if you do develop the virus in the days ahead, your infectiousness is highest in the first few days, and you can't be sure when that might be.

There's news on home tests as well. On this week's reporter's call, the CDC said there is some funding to send tests to libraries and public health departments so check to see if free tests are available. And also check prices since online and retail stores may sometimes discount home tests.

Fran Kritz is a health policy reporter based in Washington, D.C., and a regular contributor to NPR. She also reports for the Washington Post and Verywell Health. Find her on Twitter: @fkritz

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Fran Kritz