China’s COVID-19 vaccine candidate appears to be safe and provokes an immune response, preliminary studies find

Results from early-stage clinical trials of the Chinese vaccine candidate Corona Vac revealed that the formulation appeared to be safe and elicited an antibody response in healthy volunteers aged 18-59 years.

According to the results of a Phase 1/2 randomized clinical trial published in The Lancet Infectious Diseases Journal, vaccine candidates were given to participants within 28 days of the first vaccination by administering twice at 14-day intervals. It may induce an antibody reaction.

Researchers, including researchers at the Centers for Disease Control and Prevention in Jiangsu Province, China, have found the optimal dose to produce the best antibody response, taking into account side effects and production capacity.

The average level of neutralizing antibodies elicited by CoronaVac was lower than that seen in people who previously had COVID-19, but scientists based on experience with other vaccines and data from animal models. Studies that still believe that the formulation can provide adequate protection against the virus.

Since the study included only healthy adults aged 18-59 years, researchers need further research to test vaccine candidates in other age groups and people with pre-existing medical conditions. Said.

“Our findings show that Corona Vac can elicit a rapid antibody response within 4 weeks of immunization by administering the vaccine twice at 14-day intervals,” co-author of the Jiangsu Provincial Center. Fengcai Zhu says. Disease management and prevention.

“In the long run, if the risk of COVID-19 is low, two doses at monthly intervals rather than two-week intervals are better suited to elicit a stronger and more persistent immune response. It’s possible, “added Zhu.

In the current study, scientists reported the results of a Phase 1/2 clinical trial involving only participants aged 18-59 years and those who had no history of COVID-19 infection.

They said participants had never traveled to areas with a high incidence of illness and had no signs of fever at the time of recruitment.

In the first phase, scientists enrolled 144 healthy volunteers and divided them into two groups with two vaccination schedules (two injections every 14 days, or two injections every 28 days). He said he would receive one of the injections).

Within each group, participants were randomly assigned to receive either low-dose vaccines, high-dose, or placebo, they said.

The Phase 1 study stated that the overall incidence of side effects was similar in both low-dose and high-dose groups on both vaccination schedules, with the most common symptom being injection site pain. ..

Scientists said there was one severe allergic reaction within 48 hours of receiving the first dose, adding that it may be related to vaccination.

However, they said participants were treated and recovered within 3 days and did not experience a similar response after the second dose.

The study showed that Phase 2 of the study began when all Phase 1 participants completed a 7-day observation period from the first dose.

In this phase, scientists enrolled 600 healthy volunteers in the study, divided into two groups for 14- and 28-day vaccination schedules, and then either low-dose or high-dose vaccines. The dose, or placebo, said was randomly assigned to receive.

Scientists quoted the limits of the study and said that the Phase 2 trial did not evaluate the T cell response, another arm of the immune response to viral infections.

Between the Phase 1 and Phase 2 trials, the researchers said there was no difference in the reported side effects, but said the immune response was much stronger in the second phase.

“CoronaVac is one of many COVID-19 vaccine candidates being investigated in parallel. There are many vaccine technologies under investigation, each with its own strengths and weaknesses,” said a China-based biopharmacy company. Said Gang Zeng, another co-author of Sinovac Biotech.

“Corona Vac can be an attractive option because it can be stored in a standard refrigerator at 2-8 degrees Celsius, which is typical of many existing vaccines, including influenza. Vaccines can also be stored for up to 3 years. It can still be stable, “said Zeng.

However, he added that data from Phase 3 studies would be important before making recommendations on potential uses of CoronaVac.