Health Conditions A-Z Infectious Diseases COVID-19 What Are COVID-19 Booster Vaccine Side Effects? By Kaitlin Sullivan Kaitlin Sullivan Kaitlin Sullivan is a health and science journalist based in Colorado. She's been part of multiple award-winning investigations into health topics including the international medical device industry and maternal mortality in New York City. health's editorial guidelines Updated on August 4, 2024 Medically reviewed by Jane Kim, MD Medically reviewed by Jane Kim, MD Jane Kim, MD, is currently a medical editor and writer. She also consults on digital content for physician medical education. learn more Fact checked by Marley Hall Fact checked by Marley Hall Marley Hall is a writer and fact-checker for Health.com specializing in medical and health information. She uses her experience in medical research to ensure content is accurate. health's fact checking process Close Kanawa_Studio / Getty Images It's safe to get COVID shots, but you may experience side effects afterward. The temporary monovalent and bivalent booster side effects of vaccination—including chills, fever, headache, pain at the injection site, and body aches—are an immune response rather than an illness. Booster shot side effects generally only last a few days. Rare COVID booster side effects include anaphylaxis (severe allergic reaction), blood clots, myocarditis (inflammation of the heart), and tinnitus (ringing of the ears). The best prevention against COVID is to stay up-to-date on COVID vaccines, including booster shots. Learn more about what to expect from COVID-19 booster shots. What COVID Boosters Are Available? Three different boosters are available: Pfizer-BioNTech: A bivalent mRNA vaccine with two different components of SARS-CoV-2Moderna: Another bivalent mRNA vaccineNovavax: A monovalent protein subunit vaccine based on the original SARS-CoV-2 variant About the Johnson & Johnson Vaccine In the U.S., the Johnson & Johnson vaccine is no longer available. Individuals 18 and older who received a Johnson & Johnson vaccine should receive either a bivalent Moderna or Pfizer-BioNTech dose. They should be given this dose at least two months after the completed Johnson & Johnson primary series or the last monovalent booster dose. Who Is Eligible for COVID Booster Shots? Eligibility for booster shots is as follows: Moderna: Moderna's bivalent booster is approved for people ages 6 months and older who do not have a health condition preventing them from safely getting vaccinated, such as a previous allergic reaction, which is very rare.Pfizer: Pfizer's bivalent booster is approved for those ages 6 months and older.Novavax: Novavax's monovalent booster administration is available under limited circumstances. Individuals ages 12 and older may get a Novavax booster if they completed FDA-approved or authorized vaccines, did not receive previous booster shots, and cannot or will not receive an mRNA vaccine and booster dose. Common COVID Booster Side Effects Side effects from COVID-19 booster shots are similar to those from primary series vaccinations. Additionally, side effects are generally temporary and only last for a few days. Here are the side effects you should look out for. Side Effects of Moderna Booster Common Moderna booster side effects include: Chills Fatigue Headache Injection-site redness and swelling Muscle or joint pain Pain Side Effects of Pfizer-BioNTech Booster The Pfizer-BioNTech booster shares many side effects with the Moderna booster. Researchers also found that Pfizer-BioNTech booster side effects, like fatigue, fever, and bone pain, were similar to those after the second dose. Side Effects of Novavax Booster The side effects of this booster shot are similar to those of the Moderna booster. However, research shows that people who get the Novavax booster have fewer side effects like injection site pain, swelling, headache, fatigue, muscle ache, headache, or fever than those who get the Moderna or Pfizer-BioNTech boosters. Rare COVID Booster Side Effects Of more than 192 million people in the U.S. who were vaccinated against COVID with an mRNA vaccine, 1,626 developed an inflammatory heart condition called myocarditis within seven days of getting their shot. Most cases were in adolescents and men in their early 20s. Other rare reactions have been reported after vaccine administration, including constipation, dizziness, concentration difficulties, vertigo, sore throat, anaphylaxis, blood clots, hearing changes, and tinnitus (ringing of the ears). However, no other severe events besides the inflammatory heart condition mentioned above have been clearly associated with vaccination after hundreds of millions of doses administered. COVID Booster Shot Precautions Some precautions should be considered when getting COVID booster vaccines. Healthcare providers may need to administer other COVID vaccine options if a person has a history of a non-severe allergy or non-severe, immediate reaction to a COVID vaccine ingredient. People with moderate or severe acute illnesses will have to wait to get vaccinated until their illness has improved. People who have had heart muscle or heart tissue inflammation within three weeks following any of the COVID shots may not be able to get another dose. Also, individuals who had a rare condition called multisystem inflammatory syndrome (MIS) in the past three months should wait to get a booster. They should also talk to a healthcare provider about the risks. When To Contact a Healthcare Provider While it's normal to have booster side effects, talk to a healthcare provider if you have concerns about your side effects or if the effects last longer than a few days. Some symptoms also require medical attention. Seek immediate medical care if you have signs of severe reactions or allergic reactions like: Abdominal pain Chest discomfort or tightness Diarrhea Difficulty breathing Dizziness and weakness Heart palpitations Hives Low blood pressure Nausea or vomiting Slurred speech Swelling of your face and throat Tips for Reducing Booster Side Effects Ways to reduce side effects from a COVID-19 booster shot include: Dressing comfortably if you experience a feverDrinking enough fluidsKeeping your arm moving throughout the dayResting if possibleUsing a clean, cool cloth for swelling or discomfort around the injection site A Quick Review COVID booster shots can cause side effects just like the primary series doses of COVID-19 vaccines. These symptoms may include headaches, muscle pain, and swelling at the injection site. There are also rare side effects, like sore throat and vertigo, and serious side effects, like severe allergic reactions, that warrant immediate medical attention. Fortunately, in some cases, you can reduce side effects by, for example, getting rest and staying hydrated. It's normal to have booster side effects, but talk to a healthcare provider if you have concerns about your side effects or if they last longer than a few days. Was this page helpful? Thanks for your feedback! Tell us why! Other Submit 16 Sources Health.com uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Centers for Disease Control and Prevention. Vaccines for COVID-19. MedlinePlus. COVID-19 vaccines - what to expect. Yaamika H, Muralidas D, Elumalai K. Review of adverse events associated with COVID-19 vaccines, highlighting their frequencies and reported cases. J Taibah Univ Med Sci. 2023;18(6):1646-1661. doi:10.1016/j.jtumed.2023.08.004 Centers for Disease Control and Prevention. Interim clinical considerations for use of COVID-19 vaccines in the United States. U.S. Food & Drug Administration. Coronavirus (COVID-19) update: FDA authorizes Moderna, Pfizer-BioNTech bivalent COVID-19 vaccines for use as a booster dose. American Medical Association. Answering patients' questions about the bivalent COVID-19 vaccine. Centers for Disease Control and Prevention. CDC allows Novavax monovalent COVID-19 boosters for adults ages 18 and older. Centers for Disease Control and Prevention. Updated (2023–24 Formula) Novavax COVID-19 Vaccine. American Medical Association. COVID-19 booster shot patient FAQs. US Food and Drug Administration. Coronavirus (COVID-19) update: FDA shortens interval for booster dose of Moderna COVID-19 vaccine to five months. El-Shitany NA, Bagher AM, Binmahfouz LS, et al. The adverse reactions of Pfizer BioNTech COVID-19 vaccine booster dose are mild and similar to the second dose responses: a retrospective cross-sectional study. 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