(Reuters) – A single dose of Johnson & Johnson’s JNJ.N The investigational COVID-19 vaccine produced a strong immune response against the novel coronavirus in an early to mid-stage clinical trial, according to interim results released Friday.
The vaccine, called Ad26.COV2.S, was also well tolerated at two different doses, the results showed. One shot, versus a rival two-dose approach tested by Moderna Inc MRNA.O and Pfizer Inc PFE.N, could simplify the distribution of the vaccine.
However, it is not known whether the elderly, one of the populations most exposed to the virus, will be protected to the same degree as younger people with the J&J vaccine.
The trial of nearly 1,000 healthy adults, backed by the US government, began after the J&J vaccine was discovered in July to provide strong single-dose protection to monkeys.
Based on the current results, J&J on Wednesday launched a final 60,000-person trial, which could pave the way for a regulatory approval application. The company said it expects the results of this so-called Phase 3 trial by the end of the year or early next year.
The results, published on the medical site medRxiv, have not been peer reviewed. (bit.ly/2G3Ni1X)
Researchers, including those at J&J’s Janssen Pharmaceuticals unit, said 98% of participants with data available for interim analysis had neutralizing antibodies, which defend cells against pathogens, 29 days after vaccination .
However, immune response results were only available for a small number of people – 15 participants – over 65 years of age, limiting interpretation.
In participants over 65, the rate of side effects such as fatigue and muscle pain was 36%, far lower than the 64% seen in younger participants, the results showed, suggesting that the immune response in the elderly might not be as strong.
The researchers said more details on safety and efficacy will follow once the study is complete.
For now, the results justify why more studies are needed in greater numbers to look for serious side effects, Dr. Barry Bloom, a professor at Harvard TH Chan School of Public Health who was not, told Reuters. involved in the J&J trial.
“Overall, the vaccine does what you expect it to do if you were to move it to Phase 3 trials,” Bloom said.
Reporting by Vishwadha Chander and Manas Mishra in Bengaluru; Editing by Sriraj Kalluvila, Nancy Lapid and Will Dunham