Many of the people who received a single dose of the Johnson & Johnson Covid-19 vaccine in an initial clinical trial developed neutralizing antibodies against the virus around the eighth day, and by day 57, all volunteers did so, according to a published study Thursday in the Journal of the American Medical Association.
The U.S. Food and Drug Administration authorized Johnson & Johnson’s Covid-19 single dose 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 testing process. In January, J&J also published the provisional results of a large part of the vaccine test in the New England Journal of Medicine. That study showed that the vaccine was safe and generated an immune response.
For this part of the initial stage test, the Beth Israel Deaconess Medical Center in Boston recruited 25 adult volunteers who were randomly divided into five different groups. One group had a single shot, another had two. In these two groups, the scientists tried two different doses of vaccine. Another group received a placebo.
The scientists checked the antibody levels of the volunteers during the trial. For the purpose of this study, they reported the total 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 developed antibodies against the coronavirus on the eighth day. On day 57, all volunteers who received the vaccine developed neutralizing antibodies, a T cell response and a cellular immune response after just 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 be generalized to other age groups. The researchers say they will follow up with these volunteers to see exactly how long this protection can last.
J&J is currently working on several other clinical trials of the Covid-19 vaccine, including to determine whether a second dose works better. He is also studying how his vaccine works in children and will study how it works in pregnant women.