Updated June 14, 2021
Millions of Americans have received vaccinations for COVID-19 since December 2020.
The vaccines are safe and effective, but they do have some common side effects. Most side effects are mild and go away within a few days.
Vaccine clinical trial data, along with data gathered since vaccine distribution began, show that several factors may affect your side effects. Those factors include your age and your sex.
What Are the COVID-19 Vaccine Side Effects?
The most common COVID-19 vaccine side effects include:
- Pain at the injection site
- Redness or swelling at the injection site
- Muscle pain
- Swollen lymph nodes
Not all patients experience side effects after getting the vaccine. Do not worry if you did not have side effects after your vaccinations.
On April 23, 2021, the Centers for Disease Control and Prevention (CDC) and U.S. Food and Drug Administration (FDA) released a statement lifting a nationwide pause in the use of the Johnson & Johnson/Janssen COVID-19 vaccine. Federal health officials investigated cases of a rare, serious blood clot reported in some people after they received the J&J vaccine.
After their investigation, the CDC and FDA determined the risk of blood clots from this vaccine is very low and the known benefits in preventing COVID-19 are very high. The vaccine is safe and effective in preventing COVID-19.
If you receive the J&J vaccine, you do not have to take any medications to prevent blood clots. Call your doctor if you experience any symptoms related to blood clots, including:
- Shortness of breath
- Chest pain
- Leg swelling
- Persistent abdominal pain
- Severe headaches or blurred vision
- Easy bruising or tiny blood spots under your skin, beyond the injection site
The Moderna and Pfizer vaccines have not been linked to blood clots.
The Centers for Disease Control and Prevention (CDC) is monitoring reports of the heart conditions myocarditis and pericarditis in people who received the Moderna and Pfizer vaccines, especially adolescents and young adults.
According to the CDC, the reported cases were rare and happened mostly in male adolescents and young adults 16 and older. Symptoms usually presented within days of vaccination, and patients typically responded well to rest and medications.
The CDC continues to recommend vaccination for Americans 12 and older.
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How Does Age Affect COVID-19 Vaccine Side Effects?
Clinical trial data showed younger people tended to feel side effects from the COVID-19 vaccine more than older people.
The data held true for local reactions (pain, swelling, or redness at the injection site) and systemic reactions (headache, fatigue, muscle pain, fever/chills, and nausea).
- For the Pfizer-BioNTech vaccine, 88.7% of people ages 18 to 55 reported local reactions, and 82.8% reported systemic reactions. In comparison, 79.7% of people older than age 55 reported local reactions and 70.6% reported systemic reactions.
- For the Moderna vaccine, participants ages 18 to 59 reported both local and systemic reactions at a higher rate after both doses than participants 60 and older.
- For the Johnson & Johnson/Janssen (J&J) vaccine, 59.8% of participants ages 18 to 59 reported local reactions, and 61.5% reported systemic reactions. In participants age 60 and older, 35.4% reported local reactions and 45.3% reported systemic reactions.
Why do younger recipients experience more side effects? One potential reason is your immune system. Vaccines trigger a response by your immune system, which can lead to side effects. Younger people generally have more a robust immune system, which means a stronger immune response to the vaccine — and a higher rate of side effects.
How Does Sex Affect COVID-19 Vaccine Side Effects?
According to available data, women more often reported side effects to the COVID-19 vaccine than men.
In February 2021, the Centers for Disease Control and Prevention (CDC) released a report on safety data from more than 13.7 million vaccine doses given in America.
According to the study, 79.1% of the reported side effects came from women. Women had received 61.2% of the available vaccines.
Also, nearly all reported anaphylactic allergic reactions to the Pfizer and Moderna vaccines occurred in women.
These data support results from other vaccines. According to the Journal of Obstetric Gynecologic & Neonatal Nursing, women generally have a higher immune response to vaccines. They also experience side effects more often.
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Does the COVID-19 Vaccine Second Dose Cause More Side Effects?
The Pfizer and Moderna COVID-19 vaccines are two-dose vaccines, while the J&J vaccine requires one dose.
According to reported data, side effects are more common after the second dose of the Moderna and Pfizer vaccines than after the first. Side effects from the second shot may be more intense, according to the CDC. Those side effects are normal and should go away within a few days.
- Several systemic side effects — fever, chills, fatigue, headache, and muscle or joint pain — were more often reported after the second dose of the Pfizer vaccine. This was true among both younger and older participants.
- For the Moderna vaccine, 57% of participants ages 18 to 64 reported systemic side effects after the first dose, while 81.9% of participants reported systemic side effects after the second dose. Among participants age 65 and older, 48.3% reported a systemic side effect after the first dose and 71.9% reported a systemic side effect after the second dose.
What Should I Do If I Have Side Effects From the COVID-19 Vaccine?
Data show side effects from the COVID-19 vaccine may be more common in some groups of people — but the reported side effects are generally minor and go away within a day or two.
Talk to your doctor about taking over-the-counter medicines like ibuprofen, acetaminophen, aspirin, or antihistamines. They could help relieve symptoms.
Other symptoms are unlikely to come from the vaccine and may be from another cause. Cough and shortness of breath are not expected side effects of the vaccine. These may be due to COVID-19 or another cause.
Call your doctor if your symptoms get worse, don’t go away within a few days, or if you’re experiencing symptoms that aren’t common with the COVID-19 vaccine.
UPMC is currently distributing the COVID-19 vaccine in our communities. For more information, visit UPMC.com/CovidVaccine.
Aria Bendix, Business Insider, The COVID-19 Vaccine Side Effects You Can Expect Based on your Age, Sex, and Dose. Link
Centers for Disease Control and Prevention, Possible Side Effects After Getting a COVID-19 Vaccine. Link
Centers for Disease Control and Prevention, Local Reactions, Systemic Reactions, Adverse Events, and Serious Adverse Events: Pfizer-BioNTech COVID-19 Vaccine. Link
Centers for Disease Control and Prevention, Local Reactions, Systemic Reactions, Adverse Events, and Serious Adverse Events: Moderna COVID-19 Vaccine. Link
Centers for Disease Control and Prevention, Local Reactions, Systemic Reactions, Adverse Events, and Serious Adverse Events: Janssen COVID-19 Vaccine. Link
Julianne Gee, et al, Centers for Disease Control and Prevention, First Month of COVID-19 Vaccine Safety Monitoring — United States, December 14, 2020–January 13, 2021. Link
Patricia Robin McCartney, Journal of Obstetric & Gynecologic Neonatal Nursing, Sex-Based Vaccine Response in the Context of COVID-19. Link
Melinda Wenner Moyer, New York Times, Women Report Worse Side Effects After a COVID Vaccine. Link
Tom T. Shimabukuro, MD; Matthew Cole, MPH; John R. Su, MD, Journal of the American Medical Association, Reports of Anaphylaxis After Receipt of mRNA COVID-19 Vaccines in the US—December 14, 2020-January 18, 2021. Link
Headquartered in Pittsburgh, UPMC is a world-renowned health care provider and insurer. We operate 40 hospitals and 700 doctors’ offices and outpatient centers, with locations in central and western Pennsylvania, Maryland, New York, and internationally. We employ 4,900 physicians, and we are leaders in clinical care, groundbreaking research, and treatment breakthroughs. U.S. News & World Report consistently ranks UPMC Presbyterian Shadyside as one of the nation’s best hospitals in many specialties and ranks UPMC Children’s Hospital of Pittsburgh on its Honor Roll of America’s Best Children’s Hospitals.