Chinese Sinovac’s COVID-19 vaccine is 50.7% effective and has been shown to be effective against variants known as P1 and P2 which are prevalent in Brazil, according to the latest data. In addition, the efficacy rate of the Sinovac vaccine can climb to 62.3% with an interval of more than 21 days between the two doses instead of 14 days.
These results appear in the latest report released on Sunday by the Butantan Public Institute in Sao Paulo, which tested and produced CoronaVac, Sinovac’s inactivated COVID-19 vaccine.
The report published specific and comprehensive data on advanced stage trials in Brazil. This is the most detailed statistical report on a Chinese vaccine against COVID-19.
The primary efficacy against symptomatic COVID-19 is 50.7%, and the vaccine is 83.7% effective in preventing cases requiring assistance, which is an increase from 78% reported in data published in Canada. January. It was 100% effective against moderate and severe cases in the randomized, double-blind, placebo-controlled Phase 3 clinical trial involving 12,396 participants, statistics showed.
The efficacy rates revealed in this report are slightly higher than those reported in early January, due to changes in clinical data monitoring and the different criteria used to define cases of infection, spokesperson Liu Peicheng said on Monday. from Sinovac.
Researchers have found that longer intervals between the two injections can provide higher efficacy, in line with observations from many Chinese medical researchers who recommend a longer interval to maximize the level of immune antibodies.
The six severe cases of COVID-19 found in the clinical trial all occurred in the placebo group. There were 67 serious adverse events reported from 64 participants and all were determined to be unrelated to vaccination, including two deaths, the report claims.
The final results and relevant statistics are identical to those that received conditional approval from the Chinese drug regulator in February.
“This is the most detailed Phase 3 study of a COVID-19 vaccine made in China to date. Overall, it demonstrates that CoronaVac has a good safety profile, and that it is effective and protective against symptomatic infections, ”said Zhuang Shilihe, a Guangzhou-based doctor who closely monitors COVID-19 vaccines, noting that its effectiveness could be further optimized by lengthening the interval between doses.
But undeniably, compared to inactivated vaccines, the efficacy of messenger RNA (mRNA) vaccines is higher, if not much higher than some common vaccines on the market, which has raised expectations, Zhuang said.
“But that doesn’t mean inactivated vaccines aren’t qualified. Take influenza vaccines, for example: the actual effectiveness rates in many countries are between 40 and 50%, but this type of vaccine is still officially recognized and widely accepted. “
Sinovac has also submitted the detailed data to the World Health Organization (WHO) and drug regulators in countries or regions that use CoronaVac, and the relevant authorities will review these detailed figures before making approval decisions, Sinovac’s Global Times learned.
The CoronaVac has been approved for emergency use in various countries, such as Pakistan and Panama.
Some media have recently blamed CoronaVac’s effectiveness rates for being the cause of the high number of infections in Chile, citing a University of Chile study that claims that effectiveness after the first injection of CoronaVac is not than 3%.
But a source familiar with the matter told the Global Times on Sunday that the university’s report was not “comprehensive and unauthorized,” adding that it was based on “very limited” open data.
“These data were only an ‘exercise’ carried out by a research team at the university, on the basis of public data. They are very limited and very far from approaching the writing of an article, ”said this source.
Official and comprehensive data from the CoronaVac vaccine deployment will be released next week by the Chilean health ministry, Sinovac said on Sunday.
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