U.S. Department of Health & Human Services

10/28/2021 | Press release | Distributed by Public on 10/28/2021 05:38

Information About Johnson & Johnson’s Janssen COVID-19 Vaccine

Possible Side Effects

In the arm where you got the shot:

Throughout the rest of your body:

  • Tiredness
  • Headache
  • Muscle pain
  • Chills
  • Fever
  • Nausea

These side effects happen within a day or two of getting the vaccine. They are normal signs that your body is building protection and should go away within a few days.

Fainting After Vaccination

Fainting (syncope) and other events that may be related to anxiety like rapid breathing, low blood pressure, numbness, or tingling can happen after getting any vaccine. Although uncommon, these events are not unexpected, and they are generally not serious.

According to information from the Vaccine Adverse Event Reporting System (VAERS), there were 653 reports of fainting events (fainting and near-fainting) among nearly 8 million doses of J&J/Janssen COVID-19 Vaccine administered in the United States in March and April 2021. This translates to a rate of about 8 fainting events for every 100,000 doses of the J&J/Janssen COVID-19 Vaccine given. These events occurred during the recommended 15-minute wait after vaccination. It's not clear at this time whether these events were associated with the vaccine or with anxiety, possibly related to preexisting concerns some people who chose to get the one-dose J&J/Janssen COVID-19 Vaccine may have about needles or shots.

By comparison, the rate of fainting after flu vaccination in 2019-2020 was 0.05 per 100,000 doses.

Other Authorized and Recommended COVID-19 Vaccines in the United States

You should get a COVID-19 vaccination as soon as possible. Do not wait for a specific brand. All currently authorized and recommended COVID-19 vaccines are safe and effective, and CDC does not recommend one vaccine over another.

Safety Data Summary

  • In clinical trials, side effects were common within 7 days of getting vaccinated and were mostly mild. Some people had side effects that affected their ability to do daily activities.
  • Side effects were more common in people 18-59 years old compared to people 60 years and older.
  • There is a plausible causal relationship between J&J/Janssen COVID-19 Vaccine and a rare and serious adverse event-blood clots with low platelets (thrombosis with thrombocytopenia syndrome, or TTS).
    • It occurs at a rate of about 7 per 1 million vaccinated women between 18 and 49 years old.
    • For women 50 years and older and men of all ages, this adverse event is even more rare.
  • Find the latest updates on J&J/Janssen COVID-19 Vaccine and blood clots with low platelets.
  • CDC will continue to provide updates as we learn more about the safety of the J&J/Janssen COVID-19 Vaccine in real-world conditions.