The World Health Organization (WHO) issued an emergency-use listing for Sinovac’s inactivated COVID-19 vaccine CoronaVac in adults aged 18 and over, the second such authorization it has granted to a Chinese company, and the seventh listing overall, according to a FirstWord report. Sinopharm became the first non-Western COVID-19 vaccine developer to be endorsed by the UN agency after its inoculation BBIBP-CorV won WHO backing last month.
The listing paves the way for CoronaVac doses to be distributed to countries around the world through the WHO co-led COVAX facility. “The world desperately needs multiple COVID-19 vaccines to address the huge access inequity across the globe,” stated Mariângela Simão, the WHO’s Assistant-Director General for access to health products.
Previous WHO emergency listings have been granted to Pfizer/BioNTech, Johnson & Johnson, Moderna and the AstraZeneca vaccine made by two different manufacturers, SK Bio and the Serum Institute of India. The latest nod follows a recent report saying that WHO officials wanted to see more data regarding the safety of CoronaVac, as well as Sinovac’s manufacturing process to determine whether the company was meeting WHO standards.
In approving CoronaVac, the WHO highlighted the fact that CoronaVac can be stored at ordinary refrigerator temperatures, making it “very manageable and particularly suitable for low-resource settings.”
Mixed efficacy results from global studies
The WHO also said its Strategic Advisory Group of Experts on Immunization (SAGE) reviewed efficacy results showing the vaccine prevented symptomatic disease in 51% of those inoculated and prevented severe COVID-19 and hospitalization in 100% of participants in trials. The agency noted that few adults over 60 were enrolled in clinical trials of CoronaVac, “so efficacy could not be estimated in this age group,” although it is still not recommending an upper age limit “because data collected during subsequent use in multiple countries and supportive immunogenicity data suggest the vaccine is likely to have a protective effect in older persons.”
According to SAGE’s evidence assessment report, phase 3 clinical trials of Sinovac’s vaccine have been conducted in Turkey, Chile, Indonesia and Brazil with varying efficacy results. Protection against symptomatic COVID-19 at least 14 days after the second dose was 84% in the Turkish trial, but fell to 65% and 51%, respectively, in the studies conducted in Indonesia and Brazil. Meanwhile, vaccine efficacy in the Chilean study was 67% at least 14 days after two doses, and while it is known that the P.1. and B.1.1.7 variants “were circulating at the time of the study,” the SAGE report says “the extent is unknown based on available surveillance.”
Meanwhile, it is not clear how many doses either Sinovac or Sinopharm can deliver to COVAX nor when, but Simão stated “we urge manufacturers to participate in the COVAX facility, share their know-how and data and contribute to bringing the pandemic under control.”