Food and Drug Administration (FDA) said, "the data on the booster vaccines are extremely limited."
The FDA said it relied heavily on studies conducted by Johnson & Johnson and could not independently confirm many of the findings because data from the trials were not submitted in time.
"Although not independently confirmed by FDA from datasets, summaries of the data suggest there may be a benefit in a second dose administered approximately two months after the primary dose," FDA staff scientists wrote.
"Overall, data indicate that the Janssen COVID-19 vaccine still affords protection against severe COVID-19 disease and death in the United States, although the highest effectiveness estimates (including for more severe COVID-19 disease) across clinical trials and real-world effectiveness studies evaluating the Janssen COVID-19 vaccine are consistently less than the highest effectiveness estimates for the mRNA COVID-19 vaccines," FDA staff wrote in the report.
Vaccine efficacy against moderate and severe/critical COVID-19 decreased from 66.9 percent to 56.3 percent at the final analysis.
An FDA advisory group will discuss the J&J data later this week and examine the information on Moderna's submission for authorization of a booster.
The FDA report did not take a position on the benefit of a booster dose of Moderna because there's very little evidence that protection is waning. However, concerns were raised regarding Pfizer's booster request, which still ended up being authorized.
The Guardian ran an in-depth story about vaccine data that sheds light on the complexity of gathering data. "There are 64 immunization registries in the United States that gather information for states, territories, and a handful of large cities — and they aren’t connected. Meanwhile, real-time data in the U.S. public health system is virtually nonexistent," Dr. Marcus Plescia, chief medical officer for the Association of State and Territorial Health Officials.