Topline

New research based on early-stage clinical trials shows promising, yet mixed, results for Sinovac Biotech’s CoronaVac Covid-19 vaccine, which is capable of generating a “quick” immune response in individuals but produced levels of antibodies lower than those recorded in people who had recovered from Covid-19.   

Key Facts

While the Phase 1 and 2 clinical trials, which involved over 700 participants and had findings published in a peer-reviewed paper in the Lancet Infectious Diseases medical journal Wednesday, were not designed to test how effective the CoronaVac vaccine might be, the researchers believe it could still provide protection from the novel coronavirus.

Professor Fengcai Zhu, one of the study’s lead authors, believes the early findings make the vaccine “suitable for emergency use during the pandemic.” 

China has already approved Sinovac’s vaccine for emergency use — way back in August — though more extensive Phase 3 clinical trials will be needed to determine how effective the vaccine might be. 

Phase 3 trials are ongoing in Indonesia, Turkey, and Brazil, with the latter recently resuming after it was paused due to an adverse event in a participant.

Key Background 

There has been significant progress in Covid-19 vaccines in the last few weeks, with Moderna announcing its vaccine to be nearly 95% effective in preliminary results from its Phase 3 Trials and Pfizer-BioNTech announcing their intent to file for emergency authorization after finding similar results at the end of their Phase 3 trial. Both are developed using mRNA technology — which has never been approved in a vaccine before — which stands in contrast  to the more traditional inactivated virus used in CoronaVac. But while promising, much more promising than some authorities had said they were willing to accept (the U.S. Food and Drug Administration said it was willing to accept a vaccine effective in 50% of people), there is still a lot of uncertainty with these vaccines, giving hope for CoronaVac which is more traditional and less intensive in its requirements. Most problematic will be distribution, and the low temperatures required by Pfizer’s vaccine could complicate this further, if not make it entirely impractical to use in many parts of the world. Distribution, and vaccination more broadly, could take months or even years to achieve adequately around the world, and even then not much is known about how long immunity might last. It’s very possible Covid-19, once under control, could become a cyclical illness that stays with us, much like the flu, experts say.

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