Johnson & Johnson (J&J) has reported new interim data from two Phase I/IIa clinical trials where its Covid-19 vaccine as a booster induced a quick and strong rise in spike-binding antibodies.

These trials involved people who were previously inoculated with the company’s single-shot vaccine.

The single-shot Janssen Covid-19 vaccine is authorised for emergency use in the US for active immunisation to prevent the disease in people aged 18 years or above.

According to the latest data, the antibodies levels stimulated by the booster shot were nine times greater than 28 days after the administration of the primary vaccine, the company noted.

Furthermore, substantial surges in binding antibody responses were reported in subjects aged 18 to 55 years and in those aged 65 years or above who were given a lower dose of the booster.

According to the interim Phase I/IIa data reported last month, the single-shot Covid-19 vaccine generated robust neutralising antibody responses that were maintained through eight months after vaccination.

J&J Janssen Research and Development global head Mathai Mammen said: “We have established that a single shot of our Covid-19 vaccine generates strong and robust immune responses that are durable and persistent through eight months.

“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.

“We look forward to discussing with public health officials a potential strategy for our Johnson & Johnson Covid-19 vaccine, boosting eight months or longer after the primary single-dose vaccination.”

The Phase I/IIa trials were partly funded by the US Department of Health and Human Services, Office of the Assistant Secretary for Preparedness and Response, Biomedical Advanced Research and Development Authority.

J&J is currently working with the US Food and Drug Administration, US Centers for Disease Control and Prevention and European Medicines Agency among other health agencies on the use of a booster shot of its Covid-19 vaccine.

In June 2021, a new clinical study by Beth Israel Deaconess Medical Center revealed strong immune responses with the J&J vaccine.