Johnson & Johnson’s single shot COVID vaccine is set to roll out in the US after its approval, but concerns linger as to the public’s perception of its relative effectiveness.
The vaccine received an emergency use authorisation (EUA) on Saturday from the FDA, and received approval from the CDC the following day. On Sunday night White House officials stated that distribution of 3.9 million doses of the J&J vaccine would begin immediately, with J&J expecting to deliver some 16 million more doses by the end of March. These vaccines will be allocated proportionally, as per the procedure for Pfizer/BioNTech and Moderna vaccines.
At a Saturday media briefing, acting FDA Commissioner Janet Woodcock, MD, reiterated issues raised by the FDA advisory committee, that the J&J product’s lower efficacy number (70% vs 95%) may cause people to think it is less effective than the alternatives. She said that wasn’t necessarily so, urging Americans to “take the vaccine they are able to access.”
“All these vaccines meet our standards for effectiveness. They were not studied in head-to-head trials, so [they’re] difficult to compare … due to differences in development programs,” she said. (Preventing moderate-to-severe COVID illness was the J&J endpoint, whereas in the Pfizer and Moderna studies the endpoint was all symptomatic COVID.)
“We need to be clear on our messaging regarding comparisons with other vaccines,” said Jason Goldman, MD, of the American College of Physicians. “As a primary care physician, many of us are eager to vaccinate” patients and this vaccine will be “helpful in achieving that goal.”
Macaya Douoguih, MD, of J&J’s Janssen unit where the vaccine was developed, talked about the potential advantages of a one-dose vaccine, referencing the company experience with the Ebola vaccine
“For an outbreak setting, a single dose has a tremendous advantage in terms of being able to rapidly roll out mass vaccination” without the complexity of following up for a second dose, she said.
Dr Douoguih addressed the company’s planned two-dose study, saying that while a two-dose regimen might be “more immunogenic and lead to durable efficacy,” she thought there was room for both options. The two-dose option would be preferable in an ‘everyday’ COVID setting. The company was trying to enroll 16-17 year olds for additional data in a study starting next week, Dr Douoguih said.
The CDC researchers discussed preliminary data on asymptomatic infection, which assessed seroconversion between days 29 and 71. Those data showed vaccine efficacy against seroconversion was 74% (95% CI 48%-87%), but the CDC urged caution as the data was only preliminary.
“Our level of confidence in asymptomatic infection is tempered by low numbers and that is important for us to remember,” said Advisory Committee on Immunization Practices committee member Sarah Long, MD, of Drexel University College of Medicine in Philadelphia. “I appreciate the workgroup concluding the confidence is not that high.”
Source: MedPage Today
