CDC advisory committee recommends Johnson & Johnson COVID-19 vaccine, discusses emerging variants

The committee also covered the feasibility of delaying second doses of mRNA vaccines and best vaccination practices for people who have recovered from the virus.


In an emergency meeting on Feb. 28, the CDC’s Advisory Committee on Immunization Practices (ACIP) voted to recommend the Johnson & Johnson/Janssen COVID-19 vaccine for those who are 18 and older, following the FDA’s emergency use authorization of the vaccine on Feb. 27.

On March 1, the ACIP convened again to discuss dosage strategies for the two mRNA (Pfizer-BioNTech and Moderna) vaccines already in circulation, and examine their effectiveness against emerging variants of the virus.

The Committee had previously discussed the status of the Johnson & Johnson/Janssen trial at a meeting in January.

Stanley E. Grogg, DO, the AOA’s liaison to the ACIP, has shared additional relevant information about the vaccines and the emergency meetings with the AOA. Here is a summary of his reports from the Feb. 28 and March 1 meetings.

Janssen vaccine has proven effective

On Feb. 28, the Committee reviewed data which found that Janssen’s single-dose adenovirus vector vaccine is 85% effective in preventing severe COVID-19 disease seven days after vaccination, and provides 100% protection against hospitalizations and death.

The most common adverse events reported were tenderness, redness and swelling near the injection site. Other events lasting one to two days included fatigue, headache, myalgia, nausea and fever.

Taking this data into consideration, the ACIP voted to recommend the Janssen vaccine for adults.

Comparing the three vaccines

In its March 1 meeting, the committee stated that it had no preference between the authorized Pfizer, Moderna and Janssen vaccines, though it noted that with the Janssen vaccine being a single dose and more easily stored, it could speed up the vaccine rollout.

The committee further discussed the merits of delaying the second dose of mRNA vaccine past the current recommendation of three to four weeks. While there is currently insufficient data to support a specific length for an extended interval between doses, the committee concluded that if it is not possible to adhere to the recommended interval, the second dose may be scheduled for administration up to 6 weeks (42 days) after the first dose.

Vaccinating after COVID-19 infection

Recent studies have found that people with prior COVID-19 infections show strong immune responses to just one dose of an mRNA vaccine. The committee discussed the feasibility of administering just one dose to those individuals, but ultimately concluded that there is insufficient data to recommend changes to the current dosage model.

The committee re-affirmed that individuals with known current COVID-19 infection should wait until they have recovered from acute illness before receiving the vaccine, and that individuals who have received passive antibody therapy for COVID-19 should defer vaccination for at least 90 days.

Vaccinations in pregnant individuals

COVID-19 during pregnancy carries an increased risk of severe illness, and there is limited data on the safety of COVID-19 vaccines during pregnancy. Researchers are studying vaccine outcomes in this population now, the committee reported.

The committee also affirmed that pregnant individuals may choose to receive a COVID-19 vaccine when eligible. No unexpected pregnancy or infant outcomes tied to COVID-19 vaccination have been observed as of Feb. 28, it noted.

Effectiveness against variants

The prevalence of COVID-19 cases in America caused by new, expected variants appears to be between 1-2% as of Feb. 28, the committee reported. These variants appear to be more transmissible, but the vaccines in circulation are highly effective in preventing serious illness and death against them.

If you have questions about this article, please contact Dr. Grogg at

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