As the US Food and Drug Administration’s advisory panel discussed Friday whether to recommend a Johnson & Johnson booster dose, new research suggested the one-shot vaccine produces a lower but more durable immune response than the Pfizer-BioNTech and Moderna shots, which have been found to wane over time.
The findings, published Friday in the New England Journal of Medicine, come from a study of a few dozen people at Beth Israel Deaconess Medical Center in Boston, which analyzed blood samples of fully vaccinated people two to four weeks after vaccination, and then eight months later.
As was also suggested by previous studies, antibody responses from the two-shot Pfizer and Moderna messenger RNA vaccines peaked after full vaccination, and then began to decline six months later. The researchers found the decline continued after eight months. But while Johnson & Johnson’s one-shot vaccine produced a much lower initial antibody response, it remained “relatively stable” for the eight months observed, with “minimal-to-no evidence of decline,” according to the study.
Dr. Dan Barouch, who runs the virology center at Beth Israel and led the study, presented the data to the FDA’s scientific advisory committee on Friday morning, hours before the panel voted to recommend J&J’s booster for all adults at least two months after their primary dose of the vaccine.
“I think the data should be reassuring for people who received the J&J vaccine, that immune responses are stable over time,” he said. “After about eight months, the antibody responses are relatively similar among the three vaccines.”
Two to four weeks after vaccination, the researchers found the median live-neutralizing antibody titer for the Pfizer and Moderna vaccines to be about 1,790 and 5,850, respectively. But after eight months, those figures declined by 34- and 44-fold, and the trend was similar with other antibody measures.
The median levels of virus-fighting antibodies for the Johnson & Johnson shot were initially about 150 — much lower than the mRNA vaccines — but then it jumped to about 630 after eight months.
Barouch’s lab also looked at T cell responses and found those responses were stable over time, for all three vaccines.
Beth Israel codeveloped the Johnson & Johnson vaccine alongside the New Jersey-based pharmaceutical giant, and the vaccine was authorized for emergency use in the US in late February.
The Beth Israel study was done in a lab, but it is consistent with data from a preprint real-world study in New York released this month that measured the durability of the three vaccines in fully vaccinated individuals from May through August. The Pfizer, Moderna, and Johnson & Johnson vaccines were found to be 69, 78, and 70 percent effective in August against COVID-19 cases, respectively.
Barouch said Johnson & Johnson is making a different argument for a booster than Pfizer and Moderna, which sought clearance for a third dose to combat waning antibody levels. Instead, Johnson & Johnson could use a booster to increase its initially lower immune response, he said.
“Although protection is maintained over time with a one-dose vaccine, it is not in the 90 percent range; it is in the 70 to 80 percent range,” he said. “A booster could bump efficacy to a level that is substantially higher.”
Johnson & Johnson released data in September from a large clinical trial that showed a booster given two months after the first shot led to 94 percent protection against COVID-19 in the US.