Side effects, when to get it

You'll soon be able to get a new, updated dose of the COVID-19 vaccine. The Food and Drug Administration just approved new versions of the booster shots designed to offer better protection against coronavirus variants currently circulating.

With high levels of wastewater related to COVID-19 and hospitalizations increasing right before children return to school, the new vaccine may provide greater protection at a crucial time, experts tell TODAY.com.

NBC News reports that pharmacies are expected to offer the vaccinations in the coming days.

“We are seeing a significant summer surge right now,” said Dr. Natalie Azar, NBC medical fellow, during an Aug. 22 segment on the TODAY show. More than 40 states are reporting high or very high levels of COVID-19 in wastewater, according to data from the U.S. Centers for Disease Control and Prevention.

This increase is largely due to the emergence of new, highly contagious variants, particularly FLiRT strains such as KP.3 and its relative KP.3.1.1.

While the last updated vaccines offered some protection against such strains, the new variants are different enough to warrant an updated booster shot, Dr. Bernard Camins, medical director of infection prevention at Mount Sinai Health System, told TODAY.com.

“Vaccination remains the cornerstone of COVID-19 prevention,” said Dr. Peter Marks, director of the FDA’s Center for Biologics Evaluation and Research, in a press release announcing the approval.

“Given the declining immunity of the population from previous contact with the virus and from previous vaccinations, we strongly recommend that those eligible get vaccinated with a current COVID-19 vaccine to have better protection against the variants currently circulating,” the statement continued.

However, this particular dose is available earlier in the season than booster shots have been in the past, according to Camins, so it's difficult to know when to take it for the best protection.

Which variants does the new booster protect against?

All new vaccines are designed to provide better protection against newer strains, particularly the JN.1 strain that was responsible for the massive increase in cases earlier this year. The FDA advised pharmaceutical companies to use the KP.2 variant, which is a derivative of JN.1, in the fall vaccinations if possible.

Pfizer and Moderna's updated doses target KP.2, while Novavax's third option targets JN.1, NBC News reports.

KP.2 is one of the FLiRT variants that gained the upper hand over the summer, as TODAY.com previously explained. The latest estimates show that the KP.3.1.1 variant is now leading, causing about 37% of cases in the U.S. KP.3 is now responsible for about 17% and KP.2.3 for just over 14% of cases.

Another variant, LB.1, is also currently responsible for about 14% of COVID-19 cases. This is another descendant of JN.1.

However, the number of JN.1 itself has declined considerably and is now estimated by the CDC to account for only 0.2% of cases.

Who should receive the new COVID booster vaccine?

Back in June, the CDC recommended that everyone 6 months and older get vaccinated against COVID-19 this year in addition to the flu shot, Azar said. Older adults should also consider the new RSV vaccine, which was only approved last year, this fall, Camins says.

People who are in the more vulnerable groups “definitely need to get in line to get the (new COVID booster shot),” Azar added. That includes people 65 and older, people with weakened immune systems and people with certain underlying medical conditions that put them at higher risk for severe COVID-19 complications.

For those who are not yet able to get vaccinated but remain at higher risk for COVID-related complications given the current surge, Camins recommends resorting to the strategies we've used before, including wearing a high-quality mask in crowded indoor settings and avoiding such places when possible.

People in this group should also think about Paxlovid in case of a COVID-19 infection, says Camins.

Immunocompromised people who may not be as protected by one dose of vaccine can also ask their doctor about monoclonal antibody treatment, Camins says. The FDA granted emergency use authorization to the drug Pemgarda in March of this year. It may help protect this population from COVID-19 infection, Camins says.

When should you get the COVID booster shot?

If this vaccine is approved this week, it would be approved earlier in the season than other vaccines in the past. Last year's fall booster shot was approved in mid-September 2023 and protected against XBB coronavirus strains, for example. But experts predict there will be another wave later in the year, as we've seen every winter with COVID-19.

We know that vaccine protection is strongest in the first few weeks after vaccination and then wanes over the next three months. So getting vaccinated as soon as possible may mean you are less protected from a later corona wave in the winter, experts say.

This makes it difficult to determine the correct dosage. Here are some things to consider when making your decision.

Are you at high risk of severe COVID disease?

People at high risk, including older adults, should consider getting vaccinated when it becomes available because the virus is still circulating in high levels in many parts of the country, experts say.

Keep in mind that people in these categories will be eligible for another dose of vaccine later in the winter if protection from the current dose wanes, Camins says. That happened last February, when the CDC recommended another dose for older adults amid a major vaccination surge after the holidays. But, Camins adds, we don't know for sure if that will happen this year.

For people at lower risk of COVID-19 disease, deciding when to get the booster shot can be especially difficult, Azar said.

Those people probably won't be eligible for a dose later in the winter, but vaccine protection wanes after about 90 to 120 days, Camins explains. So “if your risk is low to moderate, you may actually want to wait a couple of months so you're protected when the inevitable winter surge hits,” Azar said.

Are there any situations in the future in which you are more likely to become infected?

When planning your dose, keep high-risk situations in mind, says Camins, who plans to get the vaccine before traveling next month. Think about timing your vaccination so you're protected if you have major trips planned, for example, or high-risk events like large indoor weddings.

Have you recently been infected with COVID?

If you had a COVID-19 infection during this summer surge, that's another reason to delay your next dose. People who recently had a COVID-19 infection should try to stay up to date with vaccinations, the CDC says, but they “may consider” delaying their vaccination for three months.

“We know that a lot of people got infected over the summer,” Azar said. “In that case, you might actually want to wait about three to four months before getting (the booster shot).”

Having COVID-19 will give you some protection against currently circulating strains of the virus, as TODAY.com previously explained. However, protection after infection is typically not as durable as that from vaccination, so you should still get the updated dose at some point.

Common side effects of a COVID booster vaccination

The exact side effects of a COVID-19 vaccination or booster shot vary from person to person.

In general, the CDC says people may experience:

• Pain, redness and swelling at the injection site
• fatigue
• Muscle pain
• Headache
• Fever
• chills
• Nausea

These side effects are usually temporary and mild, but may still prevent you from carrying out your usual activities for a day or two.

For more severe arm pain, you can take an over-the-counter pain reliever after vaccination, gently stretch and move your arm, or use a cool or warm compress, the CDC recommends. Don't take a pain reliever before vaccination, as it can interfere with the immune response, according to the National Foundation for Infectious Diseases. And of course, it's important to rest and stay hydrated while your body deals with the side effects.

If possible, you should take it easy the day after the vaccination.