Developed by Janssen Pharmaceuticals, a division of New Jersey-based Johnson & Johnson (J&J), this single-dose  COVID-19 vaccine was granted Emergency Use Authorization (EUA) y the U.S. Food and Drug Administration (FDA) on February 27, 2021.

  • In October 2021, the CDC recommended a booster shot for individuals 18 and older at least two months after their single dose of the Johnson & Johnson vaccine. The new CDC booster guidance allows eligible people to choose which vaccine they receive for their booster, regardless of which vaccine they received for their initial vaccination.

Important Information about the Johnson & Johnson Vaccine

  • Number of doses required: 1 dose
  • Time to reach full protection: 14 days after vaccination
  • Booster shots available: Yes, for people 18 and older at least two months after first dose
  • Additional dose for immunocompromised people: No
  • FDA status: Age 18 and up and booster dose (FDA EUA)
  • Effectiveness: Highly effective in preventing severe illness, hospitalization and death
  • Storage: Refrigeration

How the Johnson & Johnson Vaccine Works

The Johnson & Johnson vaccine is a viral vector vaccine that uses a modified version of an inactive virus (not the virus that causes COVID-19, but a different, harmless virus) to make what is called "spike protein." This triggers an immune response in our bodies, causing our immune system to produce antibodies to fight future infection from the virus that causes COVID-19. Viral vector vaccines do not affect or interact with your DNA in any way. Similar to the Pfizer (Comirnaty) and Moderna vaccines, you cannot get COVID-19 from this vaccine.

Who Can and Cannot Get the J&J Vaccine

The vast majority of people are able to get the Johnson & Johnson vaccine or any of the other approved vaccines. However, some people cannot receive it or should consult a doctor first.

  • Children under the age of 18 are not eligible to receive the Johnson & Johnson vaccine at this time. Studies are under way to test its safety and effectiveness in children.
  • People who are allergic to any of its ingredients should not receive this vaccine. Please see additional information about allergic reactions below.

Johnson & Johnson Booster Shot

The CDC recommends a booster shot for certain individuals.

The vaccine remains effective at protecting against severe illness, hospitalization and death from COVID-19, including against the Delta variant.

Public health experts have started to see some reduced protection among certain people, such as those who are older (65 years and older), work in high-risk settings or have underlying medical conditions that put them at higher risk for severe COVID-19.

A booster shot is only approved for people who are who are at least 18 years old and who:

  • Received their second dose of the Pfizer or Moderna vaccine at least six months ago and are eligible based on the CDC's criteria
  • Received the single-dose Johnson & Johnson vaccine at least two months ago

Regardless of the vaccine initially received, people eligible for a booster may choose any of the three vaccines available in the United States (Pfizer, Moderna or Johnson & Johnson).

How the Johnson & Johnson Vaccine Was Developed

Although the Johnson & Johnson vaccine was developed quickly, it still underwent the same rigorous approval process as laid out by the FDA. No safety steps were skipped. Learn more about the vaccine's development and approval process.

The Johnson & Johnson COVID-19 vaccine trials evaluated the safety and effectiveness of the vaccine in protecting against both moderate and severe COVID-19 disease. The trial included a diverse population of participants across eight countries on three continents.

Allergic Reactions and Side Effects

Please see the FDA's Fact Sheet for the Johnson & Johnson vaccine for the most up-to-date information on:

  • Vaccine ingredients
  • Side effects and what to do about them
  • Possible allergic reactions

If you have a history of immediate or severe allergic reaction to anything – especially another vaccine or injectable medicine – it is strongly recommended you talk to your doctor before getting the vaccine. This is so your doctor can confirm it is safe for you to get the vaccine.

If you have a history of severe allergic reactions, you will also be monitored for 30 minutes after your vaccination.

Other Conditions

Before you get vaccinated, you should talk to your doctor if you:

  • Have any allergies
  • Have a fever
  • Have a bleeding disorder or are on a blood thinner
  • Are immunocompromised or are taking a medicine that affects your immune system
  • Have received another COVID-19 vaccine

Updated 11/11/2021


UMMS provides our expert-reviewed content to keep our community informed. When sharing this copyrighted content, please link to our site so that critical updates are reflected.