Many of the people who received a single dose of the Johnson & Johnson Covid-19 vaccine in an early clinical trial developed neutralizing antibodies by about eight days, and by day 57, all volunteers published according to a study. Thursday in the Journal of the American Medical Association.
The U.S. Food and Drug Administration approved Johnson & Johnson’s single-dose 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 has worked in humans – and it has 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 is safe and elicits an immune response.
For this part of the earlier trial, Beth Israel Deaconess Medical Center in Boston recruited 25 adult volunteers who were randomized into five different groups. One group received a single shot, another one received two. In those two groups, scientists tried two different doses of vaccine. Another group received a placebo.
Scientists checked the antibody levels of the volunteers throughout the investigation. For the purpose of this study, they reported the total results after 71 days. The company will follow up on these volunteers for two years.
For the volunteers who received the vaccine, researchers found that about 90% of those who received the vaccine developed antibodies to the coronavirus by day 8. On day 57, all the volunteers who received the vaccine developed neutralizing antibodies, a T-cell response, and a cellular immune response after just a single dose. The reaction was even stronger on day 71.
A comment on the study: The study had its limitations. It is small and the elderly are not included in this, so it cannot necessarily be generalized to other age groups. Researchers say they will follow up on these volunteers to see exactly how long this protection can last.
J&J is currently conducting several other clinical trials with Covid-19 vaccine, including to determine if a second dose works better. It also studies how its vaccine works in children, and how pregnant women work.