Phase 3 Trial Suggests CoronaVac COVID-19 Vaccine is Safe, Protects Against Disease

A recent interim analysis of phase 3 data has suggested that CoronaVac, a vaccine developed by the Chinese biopharmaceutical company Sinovac, is safe and protects against severe disease from COVID-19.

The data was presented at this year’s European Congress of Clinical Microbiology & Infectious Diseases (ECCMID) and was published in the journal The Lancet.

“Tanriover and colleagues’ findings suggest that two doses of CoronaVac have robust efficacy (within the WHO target product profile for SARS-CoV-2 vaccines) and acceptable tolerability when administered with a 14-day interval,” Maheshi N Ramasamy, a chief investigator at the Oxford Vaccine Group and Lucy Jessop, director of public health at the National Immunization Office in Ireland said in a linked comment. “CoronaVac is also available as single- dose vials, which improves ease of administration and reduces wastage.”

The double-blind, randomized, placebo-controlled, phase 3 trial included 11,303 participants aged 18 to 59 years old who had no history of an infection with COVID-19 and produced a negative PCR and antibody test. The participants were enrolled at 24 centers throughout Turkey.

The participants received either the vaccine or a placebo intramuscularly on days 0 and 14.

Findings from the study demonstrated that the vaccine had an efficacy of 83.5% against PCR-confirmed symptomatic COVID-19 at least 14 days after the second dose. During a follow up of 43 days, there were 9 reported cases of PCR-confirmed symptomatic COVID-19 in the vaccine group, compared to 32 cases in the placebo group.

Additional findings showed that the frequencies of any adverse events were 18.9% in the vaccine group, compared to 16.9% in the placebo group. There were no reported deaths or grade 4 adverse events.

The most commonly reported adverse events were fatigue and injection site pain.

“Tanriover and colleagues’ study suggests that CoronaVac is another useful tool in the global fight against COVID-19, although more data are needed on its efficacy against emerging SARS-CoV-2 variants and on its duration of protection across different age groups and geographical settings and in the presence of comorbidities,” Ramasamy and Jessop said. “The results of ongoing effectiveness studies (NCT04747821 and NCT04789356) and immunogenicity studies (NCT04756830 and NCT04775069) are keenly awaited.”