The Johnson & Johnson (J&J) company has said that a booster shot of its COVID-19 vaccine sharply increases levels of antibodies, according to interim data from two early-stage trials.
According to the company, a second dose of the vaccine resulted in binding antibody levels that are nine times higher than the levels, 28 days after people received their first dose.
The data revealed that the binding antibodies attach to the virus but do not destroy it or prevent infection but instead, alert the immune system of its presence so white blood cells can be sent to destroy it.
Prior to now, there has previously been no evidence about the effect of the booster dose of the J&J vaccine.
The new information comes as several countries have begun offering booster doses of other vaccines to individuals considered as vulnerable, including the immunocompromised, as the Delta variant has continued to spread and even vaccinated people have caught the virus.
US Centers for Disease Control and Prevention (CDC) advisers, in particular, have been waiting for word on how to advise immunocompromised individuals who received the J&J vaccine.
According to Johnson & Johnson, studies showed significant increases in binding antibody responses in participants aged 18-55 and in those 65 years and older who received a lower booster dose.
The results were released before long-awaited results from J&J’s large, two-dose vaccine trial. A spokesman said those results will be available in the coming weeks. The head of research and development at J&J’s Janssen pharma division, Mathai Mammen, stated in a statement that, “With these new data, we also see that a booster dose of the Johnson & Johnson COVID-19 vaccine further increases antibody responses among study participants who had previously received our vaccine.”
In July, J&J published data in the New England Journal of Medicine that showed neutralising antibodies generated by its vaccine remained stable eight months after immunisation with a single dose.
