The Chinese Covid-19 vaccine candidate is safe and generates an antibody response in patients

An inactivated coronavirus-based Chinese Covid-19 vaccine candidate is safe and elicits an antibody response, preliminary results have shown.

The research, published in the Lancet Infectious Disease journal, is based on small, early-phase, randomized clinical trials involving 640 participants.

The scientists said that people 60 and older responded more slowly, and it took up to 42 days for antibodies to be detected in blood tests, compared to 28 days for participants 18 to 59 years old.

They also found that antibody levels were lower in people aged 60 to 80, compared to those aged 18 to 59.

A candidate vaccine against Covid-19 has induced antibody responses in humans in testing stages, even in people older than 60 years.

However, the researchers said the trial was not designed to evaluate the efficacy of the vaccine, so it is not possible to say whether the antibody responses induced by the vaccine, called BBIBP-CorV, are sufficient to protect against infection by coronavirus.

Study author Professor Xiaoming Yang from Beijing Institute of Biological Products Company Limited said: ‘Protecting the elderly is a key goal of a successful Covid-19 vaccine, as this age group has a higher risk of serious illness from disease.

However, vaccines are sometimes less effective in this group because the immune system weakens with age.

“So it is encouraging to see that BBIBP-CorV induces antibody responses in people 60 years of age and older, and we think this warrants further investigation.”

Inactivated vaccines are those that contain whole viruses that have died or small parts of viruses, such as proteins or sugars, that cannot cause disease.

The first phase of the study was designed to find the optimal safe dose for BBIBP-CorV, in which 192 participants ages 18 to 80 received either the vaccine or a placebo.

In the second phase of the study, designed to identify the optimal schedule for vaccination, 448 participants between the ages of 18 and 59 were randomly assigned to receive one injection of eight micrograms of vaccine or placebo, or two injections of four micrograms or placebo. at zero and 14 days, zero and 21 days, or zero and 28 days.

The researchers said no serious adverse events were reported within 28 days of the final vaccination, while the most common side effect was pain at the injection site.

The graphic shows the development of the inactivated vaccine, BBIBP-CorV, which is being tested and produced through clinical trials at the Institute of Biological Products of Beijing Company Ltd.

A small number of participants reported experiencing fever, but there were no clinically significant changes in organ function detected in laboratory tests in any of the groups, they added.

The highest antibody responses were elicited by two four-microgram doses of the vaccine given on days zero and 21 or zero and 28, the researchers said.

Professor Yang added: “Our findings indicate that a booster injection is necessary to achieve the highest antibody responses against Sars-CoV-2 and could be important for protection.

“This provides useful information for a phase three trial.”

The authors said their study had some limitations, one of which includes a short follow-up of just 42 days.

They added that the study did not include children and adolescents under the age of 18, and said trials with these groups will be carried out when the full analysis of the data from the adult groups is completed.