You have already gotten your COVID-19 vaccinations. You may have even had a booster shot. But the more you hear about Omicron and even newer variants of COVID, you start to wonder if you need another shot.

Booster shots are nothing new. Other vaccinations, such as HPV, require boosters because your immunity against these severe illnesses can start to decline with time, which puts you at an increased risk of actually catching that illness.

When it comes to coronavirus vaccinations, the Centers for Disease Control and Prevention (CDC) continues to monitor the safety and effectiveness of these vaccines in protecting against COVID. Here are some of the most important things to know about the COVID-19 vaccine booster and how you can determine if you can benefit from a vaccine booster shot.

Can I get a COVID booster shot?

Booster shots of the COVID-19 vaccines have been approved by the Food and Drug Administration (FDA) for all individuals older than 5 who have received the Pfizer-BioNTech vaccine and all individuals older than 6 who have received the Moderna vaccine. Mixing and matching booster shots has been authorized, which gives individuals more flexibility in choosing their booster shot. Meaning, if you had the Johnson & Johnson vaccine, you can get the Moderna or Pfizer booster for your second shot. Or, if you had the Pfizer vaccine, you can get the Moderna booster for your third shot. And if you received a Novavax primary vaccine series, you can get either the Moderna or Pfizer boosters.

The COVID-19 virus continues to change into new variants over time. In the fall of 2022, updated bivalent boosters from Pfizer and Moderna became available to individuals older than 5. The new bivalent boosters protect against a strain of the original virus as well as a strain of the Omicron variant.

When can I get a COVID booster shot?

In most adults and children, a primary vaccine series is recommended (usually two doses of Moderna or two doses of Pfizer). In children aged 6 months to 4 years, the primary Pfizer-BioNTech vaccine series consists of three doses.

The CDC recommends that all individuals older than 5 receive an updated bivalent vaccine if it’s been at least 2 months since their primary vaccine series (with or without an original monovalent booster vaccination). The manufacturer of your previous vaccinations doesn’t matter—you can get either the Pfizer or Moderna bivalent booster.

The guidance continues to change as understanding of the virus changes and new variants, like the Omicron BA.2, BA.4 and BA.5 variants emerge. “At this time, we recommend frequently checking the CDC’s website to stay up-to-date on booster guidelines,” says Sanjeev Jain, MD, a board-certified allergist and immunologist at Columbia Allergy.

Can I get the booster shot after having COVID?

You should get a COVID vaccine series and bivalent booster even if you’ve already had COVID-19. The shots provide extra protection because natural immunity wanes over time. If you currently have COVID-19, the CDC recommends waiting 3 months after the start of symptoms or receiving a positive test to get the bivalent booster; this is believed to maximize the vaccine’s effectiveness. If you have received monoclonal antibodies or convalescent plasma for COVID-19, updated CDC guidelines report that you do not have to wait to get vaccinated.

Why do I need a booster shot for COVID?

As of Nov. 30, 2022, over 267 million Americans have received a primary COVID-19 vaccine series. Of those fully vaccinated, around 40 million people have received a bivalent booster.

“Like all vaccines, the efficacy of the COVID vaccine lessens over time, and research is still underway to understand what the decrease looks like for COVID specifically,” explains Beth Beatriz, Ph.D., epidemiologist and public health expert at parentingpod.com. This vaccine isn’t the same as a light switch, where one day it works, and the next it doesn’t.

How long after a COVID booster shot are you protected?

How long the COVID-19 vaccine works depends on several factors, including how much of the virus you’re exposed to and your own immune response. That said, around three months after vaccination, there appears to be a decline in the COVID vaccine’s effectiveness, from about 92% to 75%, according to the health officials at the CDC.

“I want to emphasize here that even at 75% effectiveness, the COVID vaccines are still highly effective in reducing serious illness and death,” says Beatriz. Still, recent studies from Moderna have been able to look at those who were vaccinated more than a year ago versus within the past eight months. If you were recently vaccinated, you may be less likely to get COVID than those who were vaccinated more than a year ago.

Dr. Jain agrees: “Pfizer, Johnson & Johnson, and Moderna are all tracking data in regard to the longevity of the immune response and antibodies produced from these vaccines.” Researchers are continuing to monitor vaccinated individuals for a decrease in COVID antibodies to determine if or when a booster is needed.

This is especially true when it comes to the appearance of new variants. At a minimum, Dr. Jain says, a booster should give you good immunity against the virus for at least six months, as the original vaccines did.

In addition, different factors may improve how well the vaccine works, such as exercise. According to new research, engaging in moderate exercise such as walking for 90 minutes after receiving your COVID-19 vaccination or booster may improve the vaccine’s efficacy by increasing antibody response—without worsening side effects.

What are the common COVID vaccine booster shot side effects?

For the most part, you can expect similar side effects to the booster that you might have experienced from your first vaccine doses. These can include:

Injection site discomfort, redness, and swelling
Headache
Fatigue
Chills
Muscle aches
Joint pain
Fever
Nausea
Swelling of the lymph nodes

“The main difference in side effects between the original vaccine and the booster was that more participants noted lymph node swelling in the underarm on the side the vaccine was administered,” Dr. Jain explains.

This can be a normal response of your immune system and is generally not a concern. In fact, it can be a sign your body is mounting a defense against illness. Reports have shown that Pfizer and Moderna vaccines are linked to more underarm swelling than with other vaccinations. It’s possibly due to the fact that these are mRNA vaccines, which are a relatively new type of vaccine that may be stimulating a higher immune response than other types of vaccines.

As far as the updated bivalent vaccine side effects are concerned, some preliminary studies suggest that the severity of side effects with the bivalent vaccine is greater than the severity of those with the monovalent vaccine. In a small study of 76 healthcare workers, more subjects who received the bivalent vaccine reported an inability to work than those who received the monovalent vaccine. However, there have been no unique side effects reported that you haven’t already seen before with the original monovalent vaccine. Although the bivalent vaccine now targets more than one strain of COVID-19, the side effects of the bivalent and monovalent vaccine should be the same.

Where can I get a COVID booster shot?

You can get a COVID booster shot at most major pharmacies or your healthcare provider’s office. Go to vaccines.gov to find a location near you. As with the original vaccines, COVID-19 boosters are free of cost regardless of your insurance or immigration status, according to a White House press briefing.

Here are some things to keep in mind when getting your booster:

Make sure you bring your CDC-issued COVID-19 Vaccination Record card to your appointment.
It’s not known if taking over-the-counter (OTC) pain medications, such as Tylenol (acetaminophen), Advil (ibuprofen), or aspirin will affect your booster shot. It’s best to avoid these medications until after you receive the vaccine.
Generally, you can take OTC medications after your booster, but make sure you talk to your healthcare provider first.