As of April 25, 2021 the CDC and the U.S. Food and Drug Administration (FDA) recommend use of Johnson & Johnson’s Janssen (J&J/Janssen) COVID-19 Vaccine resume in the United States, after a temporary pause. The information below is an excerpt from the CDC’s updated recommendations on the J&J/Janssen vaccine.

What you need to know:

• Reports of adverse events following the use of J&J/Janssen vaccine suggest an increased risk of a rare adverse event called thrombosis with thrombocytopenia syndrome (TTS). Nearly all reports of this serious condition, which involves blood clots with low platelets, have been in adult women younger than 50 years old.
  
• A review of all available data at this time shows that the J&J/Janssen COVID-19 Vaccine’s known and potential benefits outweigh its known and potential risks.
  
• However, women younger than 50 years old should be aware of the rare but increased risk of this adverse event and that there are other COVID-19 vaccine options available for which this risk has not been seen.
  
• CDC and FDA will continue to monitor the safety of all COVID-19 vaccines.
  
• Seek medical care right away if you develop any of the symptoms below after receiving the J&J/Janssen COVID-19 Vaccine.
  
• If you have any questions or concerns, call your doctor, nurse, or clinic.

J&J/Janssen Vaccine Questions and Answers

What if I got or want to get the J&J/Janssen COVID-19 Vaccine?

For three weeks after receiving the vaccine, you should be on the lookout for possible symptoms of a blood clot with low platelets. These include:

• Severe or persistent headaches or blurred vision
• Shortness of breath
• Chest pain
• Leg swelling
• Persistent abdominal pain
• Easy bruising or tiny blood spots under the skin beyond the injection site

Seek medical care right away if you develop one or more of these symptoms.

Does CDC recommend vaccination with the J&J/Janssen COVID-19 Vaccine resume?

Yes. The Advisory Committee on Immunization Practices (ACIP) and CDC recommend vaccination with the J&J/Janssen COVID-19 Vaccine resume among people 18 years and older. However, women younger than 50 years old should be aware of the rare but increased risk of thrombosis with thrombocytopenia syndrome (TTS). TTS is a serious condition that involves blood clots with low platelets. There are other COVID-19 vaccine options available for which this risk has not been seen.

What do we know about the J&J/Janssen COVID-19 Vaccine and possible health problems?

Since use of COVID-19 vaccines began in the United States, scientists and doctors have constantly and carefully reviewed all reports of vaccine side effects and adverse events. As of April 23, 2021, more than 8 million doses of the J&J/Janssen COVID-19 Vaccine had been given in the United States. As of April 23, 2021, experts reviewing safety reports for this vaccine found 15 reports of women who got the J&J/Janssen COVID-19 Vaccine and later developed thrombosis with thrombocytopenia syndrome (TTS). TTS is a serious condition that involves blood clots with low platelets.

These reports suggest an increased risk of TTS one to two weeks after vaccination with the J&J/Janssen COVID-19 Vaccine for women under 50 years old. For all women, this is a rare adverse event. For women 50 years and older and men of all ages, the adverse event is even more rare. Reports show that symptoms of this adverse event started between 6 and 15 days after vaccination.

What do I need to know about possible safety issues with all COVID-19 vaccines?

COVID-19 vaccine safety is a top priority for the federal government, and reports of health problems following COVID-19 vaccination are taken very seriously.

Detecting these rare adverse events tells us that the systems in place to monitor the safety of these vaccines are working. The thrombosis with thrombocytopenia syndrome (TTS) reports were detected early, and the pause reflected the federal government’s commitment to transparency and safety as CDC and FDA gathered and reviewed additional data. COVID-19 vaccines have undergone and will continue to undergo the most intensive safety monitoring in U.S. history.

Learn more about how vaccine safety systems work.

If you experience any adverse events after vaccination, report them to v-safe and the Vaccine Adverse Event Reporting System (VAERS).

Has this issue been seen with the other COVID-19 vaccines?

No. As of April 23, 2021, thrombosis with thrombocytopenia syndrome (TTS)—blood clots with low platelets—has not been linked to the Pfizer-BioNTech or Moderna COVID-19 vaccines after more than 210 million doses administered.

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The information above is an excerpt from the CDC’s updated recommendations on the J&J/Janssen vaccine that was published on April 25, 2021.