An experimental COVID-19 vaccine appeared to be safe and triggered an immune response in healthy people, according to preliminary results of a small, early-stage clinical trial.
The study of the vaccine based on inactivated whole SARS-CoV-2 virus (BBIBP-CorV) included more than 600 volunteers in China, ages 18 to 80. By the 42nd day after vaccination, all had antibody responses to the virus, according to researchers.
The vaccine was safe and well-tolerated at all doses tested, study leaders reported. The most common side effect was pain at the injection site. There were no serious adverse reactions.
The findings were published Oct. 15 in The Lancet Infectious Diseases journal.
Similar results were reported from a previous trial for a different vaccine also based on inactivated whole SARS-CoV-2 virus. That trial was limited to people under age 60.
The new trial found that people 60 and older responded more slowly to the vaccine. It took 42 days for antibodies to be detected in all of them, compared to 28 days among 18- to 59-year-olds.
Antibody levels were also lower in 60- to 80-year-olds compared with the younger volunteers.
“Protecting older people is a key aim of a successful COVID-19 vaccine as this age group is at greater risk of severe illness from the disease. However, vaccines are sometimes less effective in this group because the immune system weakens with age,” said study co-author Xiaoming Yang, a professor at Beijing Institute of Biological Products Company Limited.
“It is therefore encouraging to see that BBIBP-CorV induces antibody responses in people aged 60 and older, and we believe this justifies further investigation,” Yang said in a journal news release.
Because the trial wasn’t designed to assess the effectiveness of the BBIBP-CorV vaccine, it’s not possible to know whether the antibody response it triggered is strong enough to protect people from infection with the new coronavirus.
After the researchers complete a full analysis of data from the adults, they plan to test the vaccine in children and teens under age 18.
Larisa Rudenko, a researcher at the Institute of Experimental Medicine in St. Petersburg, Russia, wrote an editorial that accompanied the findings.
She said more “studies are needed to establish whether the inactivated SARS-CoV-2 vaccines are capable of inducing and maintaining virus-specific T-cell responses.”
The U.S. Centers for Disease Control and Prevention has more on COVID-19.
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