The Johnson & Johnson Vaccine

About the Vaccine

The Johnson & Johnson COVID-19 vaccine has been approved by the Food and Drug Administration (FDA) for use in preventing COVID-19. The vaccine also goes by the name Janssen, which is the Johnson & Johnson pharmaceutical unit responsible for developing the vaccine. The Johnson & Johnson vaccine works differently than the two previously approved vaccines, Pfizer-BioNTech and Moderna. It utilizes an adenovirus-vector strategy, in which a dormant cold virus delivers genetic instructions to cells for building a spike protein found on SARS-CoV-2. The body’s immunological system responds to this spike protein by producing antibodies that will effectively block infection if the vaccinated person comes into contact with SARS-CoV-2.

How Is the Vaccine Delivered?

By intramuscular injection.

How Many Injections Are Required?

The Johnson & Johnson vaccine begins with a single injection. Currently, those who received the Johnson & Johnson vaccine and who meet certain criteria, are eligible for a booster dose of the Pfizer or Moderna vaccine two months after their initial Johnson & Johnson dose. 

Is There an Age Limit on Who Should be Vaccinated?

Yes. The Johnson & Johnson vaccine is recommended only for individuals who are age 6 months of age or older.

Was the Vaccine Tested Before Release?

Yes. The vaccine was comprehensively evaluated for safety and efficacy in clinical settings, utilizing the standard protocols for all FDA emergency use drug approvals. 

What Should I Do if I Have Had the Vaccine?

It is important to note that if you have had the vaccine within or more than three weeks ago, the risk of any potential adverse reactions is very low at this time. If you have received the vaccine within the last three weeks, your risk is still very low and will decrease over time.

You should seek immediate medical treatment if you develop any of the following symptoms:

  • Leg swelling
  • Tiny red spots on the skin
  • New or easy bruising
  • Shortness of breath
  • Severe headache
  • Severe abdominal pain
  • New neurologic symptoms

How Effective Was the Vaccine in Testing?

Based on clinical trials, Johnson & Johnson reports the vaccine as 66 percent effective in preventing moderate to severe COVID-19 illness and 85 percent effective in preventing severe COVID-19 illness from the original form of COVID-19. This effectiveness varied by region, with effectiveness in preventing moderate and severe illness reaching 72 percent in the United States. The Johnson & Johnson vaccine also appears to be effective against some of the new SARS-CoV-2 variants, including B.1.351 in South Africa.

Does the Vaccine Have Side Effects?

In some persons, yes. Included among the symptoms are swelling at the injection site, headache, joint and muscle pain, fever, fatigue, and nausea. The side effects are usually transient and mild, and can be taken as evidence that the vaccine is working to create an immune response. Severe side effects, such as allergic reactions, are rare.

The vaccine was temporarily paused in April 2021 for further analysis of blood clotting concerns. Women under the age of 50 should be aware of the risk of a rare blood clotting syndrome associated with the vaccine. If you are concerned about a possible allergic or severe reaction, please consult with your medical provider prior to receiving the vaccine.

How Common Are the Side Effects?

Side effects were limited to a small minority of participants in the clinical trials.

Are There Persons for Whom the Vaccine Is Contraindicated?

Persons who are allergic to any of the vaccine’s ingredients, or who have had an allergic reaction to a similar vaccine in the past should avoid the vaccine. To learn more about rare allergic reactions, see here. If you are pregnant or have questions about the vaccine and your personal health concerns, please consult with your provider prior to vaccination.

Do I Need to Share with My Provider Any Ongoing Health Conditions Prior to Being Vaccinated?

Yes. Let him or her know if you:

  • Are pregnant or breastfeeding
  • Have a fever
  • Have allergies
  • Have a weakened or compromised immune system
  • Have a bleeding disorder or are on blood-thinning medications
  • Have already received another COVID-19 vaccine

In rare circumstances, you may be advised to delay vaccination until a later date. 

Will I Receive a Proof of Vaccination?

Yes. Healthcare providers, including Baptist Health, are providing documentation with every injection.