Nigeria might require fresh donation of booster doses of Pfizer-BioNtech COVID-19 vaccines as studies from the U.S. and Israel suggest that the efficacy of the vaccine fades over time.
The biopharmaceutical companies confirmed in April that immunity from RNA vaccine remains intact six months after the second dose. But with fresh concerns of waning protection, the company is considering that a booster dose would be safe and effective in fighting the virus and new variants.
Nigeria expects over three million doses of the Pfizer vaccines to arrive this month, donated by US and might mean booster doses would be needed.
The company detailed the data in a presentation it will deliver to a meeting of outside advisers to the US Food and Drug Administration on Friday, a Bloomberg report said. The panel is expected to make final recommendations for whether booster shots should be administered.
“Real-world data from Israel and the United States suggest that rates of breakthrough infections are rising faster in individuals who were vaccinated earlier,” Pfizer said in its presentation, which was posted on the FDA website.
The decrease in effectiveness is “primarily due to waning of vaccine immune responses over time,” rather than the delta variant, Pfizer researchers said in the presentation.
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According to a meeting agenda the FDA posted on its website, the Friday panel meeting will include presentations from the Centres for Disease Control and Prevention, FDA staff, researchers from Israel and the U.K., along with Pfizer.
Officials from Israel will present data from that country on booster protection against infections and severe disease, according to the agenda, and a professor of medical statistics from the University of Bristol will present data on real-world vaccine effectiveness.
FDA staff also posted its report for the panel’s consideration Wednesday, summarizing much of the same data that Pfizer presented earlier.
Like Pfizer, the staff found that a booster shot of the Pfizer vaccine was safe and raised antibody levels.
Still, the staff said it hasn’t yet independently reviewed or verified the underlying data or conclusions of some relevant studies, such as the Israel study, which will be summarised in Friday’s meeting.
The staff noted that the likely benefit of a booster shot would depend on how much the third shot reduces disease relative to the first two.
If the first two shots are still highly effective, then the efficacy of the booster shot “is likely to be more limited,” the staff said.
Overall data in the U.S. indicate that the first two shots of the vaccine still protect against severe disease and death, the staff said.
The staff also noted that it is not currently clear whether there will be an increased risk of inflammation of the heart and heart lining after a booster shot, and that potential risks of a booster shot also must be considered. It didn’t offer a clear indication of which way the agency was leaning, which it often does before meetings.
