Many of the people who received a single dose of the Johnson & Johnson Covid-19 vaccine in an early clinical trial developed neutralizing antibodies to the virus by about day eight, and by day 57 all had volunteers, according to a published study. Thursday in the Journal of the American Medical Association.
The U.S. Food and Drug Administration approved Johnson & Johnson’s one-time dose of Covid-19 vaccine in February. This is one of the first peer-reviewed studies to show how the single dose of the J&J vaccine worked in humans – and it worked well.
The company released data during the trial process. In January, J&J also published interim results of a larger portion of the vaccine trial in the New England Journal of Medicine. That study showed that the vaccine was safe and elicited an immune response.
For this part of the early-stage study, the Beth Israel Deaconess Medical Center in Boston recruited 25 adult volunteers who were randomized into five different groups. One group got one shot, another two. In those two groups, scientists tried two different vaccine doses. Another group was given a placebo.
Scientists checked the antibody levels of the volunteers during the trial. For this study, they reported the overall results after 71 days. The company will monitor these volunteers for two years.
For the volunteers who received the vaccine, the researchers saw that about 90% of those who received the vaccine had developed antibodies to the coronavirus by day eight. By day 57, all volunteers who received the vaccine had developed neutralizing antibodies, a T cell response, and a cellular immune response after only a single dose. The response was even stronger on Day 71.
A note about the study: The study had its limitations. It is small and the elderly were not included, so it cannot necessarily be generalized to other age groups. Researchers say they will be monitoring these volunteers to see exactly how long this protection lasts.
J&J is currently working on several other clinical studies of Covid-19 vaccines, including to determine if a second dose works better. It is also examining how the vaccine works in children and will examine how it works in pregnant women.