What Are the 2024 COVID Vaccine Side Effects? A Breakdown

COVID and flu season is coming sooner than you might think, and getting up to date with vaccines is the best way to protect yourself in the months ahead. This year’s COVID vaccine is a little different from previous versions, not to mention that there are three different options for your shot this year (more on that in a moment). So it’s safe to say that you may have some questions before making your appointment, including, “What are the new COVID booster side effects?”

Meet the Experts: Amesh A. Adalja, M.D., senior scholar at the Johns Hopkins Center for Health Security; David Cennimo, M.D., infectious disease expert and associate professor of medicine & pediatrics at Rutgers New Jersey Medical School; Richard Watkins, M.D., an infectious disease physician and professor of medicine at the Northeast Ohio Medical University.

To help you be informed before you get your annual jab, we tapped experts to answer all of your burning questions. Here’s what you need to know about the new vaccine, plus potential side effects to keep in mind.

There are three different COVID vaccines to choose from this season: two mRNA vaccines from Pfizer and Moderna, and a protein-based vaccine from Novavax. These vaccines replace the previous COVID-19 vaccine that was available and target strains that are more relevant to this year’s virus season.

The latest COVID vaccines are updated to better reflect the currently circulating strains of the SARS CoV-2 virus, says David Cennimo, M.D., infectious disease expert and associate professor of medicine & pediatrics at Rutgers New Jersey Medical School. “Moderna and Pfizer updated their mRNA vaccines to target the KP.2 variant, while the Novavax is a protein-based vaccine and is targeting the JN.1 variant.” The difference is due to the timing and the manufacturing process and does not reflect any particular strategy for forecasting the future of the pandemic. Looking at the current data for variants circulating in the U.S., the KP.3.1.1 variant is leading at 58%, Dr. Cennimo points out. “This is closely related to KP.2 and JN.1, so all the vaccines available should work well,” he explains.

The virus that causes COVID-19, SARS-CoV-2, is always changing and protection from COVID-19 vaccines declines over time. Receiving an updated 2024-2025 COVID-19 vaccine can restore and enhance protection against the virus variants currently responsible for most infections and hospitalizations in the United States. With that said, the Centers for Disease Control and Prevention (CDC) points out that COVID-19 vaccination also reduces the chance of suffering the effects of Long COVID, as well as being hospitalized with COVID-19 and dying from the virus.

Everyone ages six months and older should get the 2024–2025 COVID-19 vaccine, advises Richard Watkins, M.D., an infectious disease physician and professor of medicine at the Northeast Ohio Medical University. “This includes people who have received a COVID-19 vaccine before and people who have had COVID-19 in the past,” he notes. The vaccine is also strongly recommended for pregnant people because COVID can be more severe in pregnancy and the antibodies can help protect the infant after birth, notes Dr. Cennimo.

Most certainly, anyone at high risk for severe COVID should be vaccinated, says Dr. Cennimo. Though, in the U.S., everyone is eligible to get the vaccine, those at high risk for severe disease (including pregnant women) should get the updated vaccine after it has been at least 3 months since their last COVID infection, adds Amesh A. Adalja, M.D., senior scholar at the Johns Hopkins Center for Health Security.

For most people, the best time to get the new COVID vaccine is now, says Dr. Watkins. However, the exception is that people who recently had COVID-19 may delay getting a COVID-19 vaccine for 3 months, Dr. Watkins adds. This is because “the risk of getting COVID-19 is less likely in the weeks to months following a SARS-CoV-2 infection.”

The vaccines are currently available and can be taken now, agrees Dr. Cennimo. “When people delay, there is a risk that they miss the vaccine altogether and/or they contract COVID in the interim.”

And for convenience purposes, you can get your flu shot at the same time that you receive your updated COVID vaccine. “The COVID and influenza vaccines can be given together and there is good data that the safety and effectiveness is not compromised,” says Dr. Cennimo.

The most important thing to know is that the COVID vaccine is safe and effective, says Dr. Watkins. With that said, side effects from the COVID vaccine are rare, says Dr. Cennimo, and they usually resolve after a day or two.

Per Dr. Watkins, the most common side effects include:

• Pain, redness or swelling at the injection site
• Fatigue
• Headache
• Muscle pain
• Chills
• Fever
• Nausea

Serious adverse reactions are even more rare, says Dr. Cennimo. “However, if anyone is experiencing signs of an allergic reaction such as trouble breathing, they need to seek immediate help.” If someone had a severe reaction to a previous vaccine, they should speak with their provider before getting a booster, Dr. Cennimo advises.

If you are experiencing some discomfort after your jab and are looking for relief, feel free to take acetaminophen, ibuprofen, or naproxen to minimize side effects, Dr. Adalja recommends.

Dr. Watkins adds that using a warm compress on the injection site can also help to relieve any discomfort and bring down any swelling.

If you have any severe symptoms or if your mild symptoms persist beyond a few days, you should consult with your doctor, Dr. Watkins advises. Dr. Adalja agrees, saying that if your side effects last for more than two days or the side effects interfere with your ability to perform daily activities, you should seek medical attention to rule out any serious concerns.