New COVID-19 vaccines tested, authorization changes in progress for existing vaccines

The FDA further limited use of the Johnson & Johnson (Janssen) vaccine and scheduled advisory committee meetings on other vaccine questions. Two non-mRNA vaccines showed effectiveness, and other studies looked at antibody prevalence, home test accuracy, and long-term symptoms.

On May 5, the FDA limited authorized use of the Johnson & Johnson (Janssen) COVID-19 vaccine to adults who either can't or won't receive one of the mRNA vaccines. The agency based the change on an analysis of the risk of thrombosis with thrombocytopenia syndrome associated with the vaccine, according to a press release. The agency also recently scheduled COVID-19-related meetings of its Vaccines and Related Biological Products Advisory Committee: June 7 to consider authorization of the Novavax vaccine for adults, and June 8, 21, and 22 to discuss authorization of the Moderna and Pfizer-BioNTech vaccines for younger children. On June 28, the committee will discuss whether the SARS-CoV-2 strain composition of the vaccines should be modified, and if so, which strain or strains should be selected for the fall.

Trials of two COVID-19 vaccines developed by new methods were published by the New England Journal of Medicine on May 4. The ZF2001 vaccine, which contains a dimeric form of the receptor-binding domain of SARS-CoV-2 and aluminum hydroxide as an adjuvant, was tested in Uzbekistan, Indonesia, Pakistan, Ecuador, and China. It was found to be 75.7% effective against symptomatic COVID-19, 87.6% against severe infections, and 86.5% against death due to COVID-19.

The other vaccine used coronavirus-like particles that are produced in plants and display the prefusion spike glycoprotein of the original strain of SARS-CoV-2 combined with an adjuvant. The study found efficacy ranging from 69.5% against symptomatic infection to 78.8% against moderate to severe disease. It was conducted in Argentina, Brazil, Canada, Mexico, the United Kingdom, and the U.S. and was funded by Medicago.

An accompanying editorial titled “Does the World Still Need New Covid-19 Vaccines?” noted that both of these vaccines offer the advantage of not requiring extreme cold-chain procedures for storage but that limitations of the studies include the absence of data in elderly people or specific to omicron.

“With more vaccine platforms available, we can possibly improve decision making regarding the selection of a vaccine, since different vaccine platforms may be more suitable for certain age groups, certain subpopulations (e.g., those with underlying immune-compromising or other medical conditions), and pregnant women. We may increasingly need to mix and match vaccines to leverage the benefits of each of these platforms,” the editorial said.

In other COVID-19 research, a study published by MMWR on April 26 reported the prevalence of antibodies due to infection from COVID-19 in the U.S. in December 2021 through February 2022: 57.7% overall, ranging from 75.2% in children ages 0 to 11 years to 33.2% in those ages 65 years or older.

A comparison of home antigen and polymerase chain reaction tests for SARS-CoV-2, published by JAMA Internal Medicine on April 29, concluded that symptomatic patients with an initial negative home test result should test again one to two days later.

Finally, a study published by The BMJ on April 27 validated a questionnaire for assessing patients' ongoing symptoms of COVID-19.

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