Janssen COVID-19 Vaccine

The Janssen (Johnson and Johnson) COVID-19 vaccine is administered as a single intramuscular injection.  It received FDA Emergency Use Authorization on 27 Feb 2021 for individuals age 18 and up.  It is a replication incompetent recombinant adenovirus type 26 vector expressing the SARS-CoV-2 Spike protein.  In other words, this is an adenovirus that has been biologically engineered to be incapable of replicating and to display the SARS-Co-V-2 Spike protein to your immune system in order to produce immunity to the SARS-CoV-2 virus.  The full benefit from the vaccine occurs 4 weeks after the injection. It provides a 72% reduction in risk of moderate to severe COVID-19 infection and 85.9% reduction in the risk of severe COVID-19 infection in the United States.  The reduced risk for severe COVID-19 infection in South Africa was 81.7%.


This vaccine is not a live virus vaccine and can be given to immunocompromised patients, including patients on immunosuppressant therapy (examples include prednisone, methotrexate, and biologic DMARDs).  However, currently available data does not establish safety and efficacy in immunocompromised patients.  It is possible that the vaccine may not be as effective in immunocompromised patients.  I recommend that my patients receive this COVID-19 vaccination when it is available locally, but continue to practice social distancing, wearing masks, and frequent hand washing.


It is contraindicated (cannot be given to) patients with a history of severe allergic reaction (anaphylactic shock and angioedema) to any of the components of the vaccine.  Each dose of the Janssen COVID-19 Vaccine includes the following ingredients: 

500,000,000,000 particles of the Ad26 vector expressing the SARS-CoV-2 spike protein. 

Citric acid monohydrate (0.14mg), trisodium citrate dihydrate (2.02 mg), ethanol (2.04 mg), 2-hydroxypropyl-B-cyclodextrin (25.5 mg), polysorbate-80 (0.16 mg), sodium chloride (2.19 mg) and <-/15 mcg of host cell proteins or host cell DNA.

Note that there are no avian proteins.  I expect patients with egg and feather allergies to be able to take this vaccine.

Hives or urticaria occurred in 5 out of the 21,895 patients who received the vaccine in the clinical trials.


The side effect profile of this vaccine is as follows:

Pain at the injection site (48.6%)

Fatigue (38.2%)

Headache (38.9%)

Muscle pain (33.2%)

Nausea (12.3%)

Fever (3.1%)

Injection site swelling (7%)

Injection site redness (4.6%)

It is ok to take acetaminophen, ibuprofen or naproxen to manage these side effects (unless you have conditions that preclude the use of these medications). 

The CDC and FDA have released a joint statement on April 13, 2021 recommending pausing vaccination with Janssen’s (J&J’s) COVID-19 vaccine due to the risk of development of a rare and severe blood clot combined with low platelet counts.

Of the 6.85 million doses of Janssen vaccines administered in the United States, six cases of cerebral venous sinus thrombosis (CVST) with low platelet counts have been reported. The cases occurred in women ages 18 and 48, and the symptoms developed between day 6 and 13 post vaccination. The most common symptoms of CVST are headache, seizures, altered consciousness, or other neurological symptoms. People who have received Janssen’s vaccine and develop the above symptoms or severe headache, abdominal pain, leg pain, or shortness of breath within three weeks after vaccination should contact their healthcare provider.

For patients who have had COVID-19 already, the chance of reinfection is very low in the first 90 - 180 days after initial infection.  They should receive vaccination after their COVID-19 symptoms have resolved and their quarantine period has ended.  It is ok to delay the vaccine for 90 - 180 days after infection.



Jeffrey Feinstein, MD

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