Analysts say the effectiveness rate of Sinovac’s Coronavac vaccine in Brazil – the lowest among its global competitors – could affect international confidence in Chinese vaccines and hamper Beijing’s attempt to restore its image by early mismanagement of the initial outbreak by supplying Covid-19 vaccines to developing countries .
“The Butantan Institute and the government of Sao Paulo report that the coronavirus vaccine achieved an overall efficacy rate of 50.38% in the clinical study conducted in Brazil, in addition to (an efficacy rate of) 78% for mild cases and “100% for moderate and severe cases of Covid-19. All rates are higher than the 50% level required by the WHO (World Health Organization),” reads the statement released on Tuesday.
The razor-sharp margin for legal approval is likely to cause concern among scientists, as the Butantan Institute last week released partial “clinical efficacy” results that were 78% to 100% effective in preventing infections.
The state body funded Phase 3 trials of the vaccine, involving 13,000 health workers in eight Brazilian states.
“In terms of the overall effectiveness of the analysis, we met the requirements of the World Health Organization by 50.38%,” Ricardo Palacios, medical director for clinical research at the Butantan Biomedical Center in Sao Paulo, told a news conference on Tuesday. .
However, high-ranking members of the Brazilian Ministry of Health told CNN subsidiary CNN Brasil on Tuesday that “the effectiveness is limitless”, and that is because “It is at the limit. We have to wait until ANVISA (Brazilian Health Regulatory Agency) evaluates.”
A Sinovac representative said the company was discussing the outcome but declined to comment further. The ultimate efficacy rate of the vaccine will be determined, according to the representative, by China’s drug regulator, the National Medical Production Administration.
Possible obstacle
Yanzhong Huang, a senior fellow for global health at the U.S. Council on Foreign Relations, described the 50.38% effectiveness of the Sinovac vaccine as a “disappointing” result that surprised him.
The results suggest that Coronavac is less effective than alternative vaccines developed by Pfizer-BioNTech and Moderna, which have an efficacy rate of approximately 95%.
Russia says its Sputnik V vaccine is 91% effective, while the British vaccine, developed by the University of Oxford and AstraZeneca, has an average efficacy of 70%.
Despite the worse-than-expected results, Huang said the Sinovac vaccine would still be ‘useful’ by relieving the pressure on healthcare systems and reducing potential deaths, as it is more effective for moderate and severe cases. require medical treatment.
However, its low overall efficiency could hamper Sinovac’s ability to expand its market share globally, Huang said.
Sinovac has signed agreements to supply 46 million doses of its Covid-19 vaccine to Brazil, 50 million doses to Turkey and 7.5 million doses to Hong Kong. It also supplies 40 million doses of vaccine – the vaccine concentrate before it is divided into vials – to Indonesia for local production.
“Since many countries are planning to order or have already ordered Sinovac’s vaccinations, it could undermine people’s willingness to take it, as people may question the usefulness of the vaccines,” Huang said. “It could be a possible obstacle.”
Lack of transparency
Both Sinovac and Sinopharm faced questions regarding the disclosure of data. In announcing its efficacy results, state-owned Sinopharm did not provide details on its clinical trial data. A manager of Sinopharm said detailed data would be released later and published in scientific journals without giving a timeline.
There is also the difference in results of clinical trials conducted at different sites.
After the coronavirus was largely eliminated within its borders earlier last year, Chinese drugmakers abroad had to look for places to test the effectiveness of their vaccines. But the results reported so far are far from consistent.
For example, Synopharm’s 79% effectiveness rate is lower than the 86% that the United Arab Emirates announced for the same vaccine in December.
Last week, the Brazilian agency for health regulators, ANVISA, told the Butantan Institute that in order to approve the emergency use of a vaccine, the global efficacy rate should be made public – information the institute had not yet received from Sinovac at the time. according to CNN Brasil sources.
ANVISA will meet on Sunday to decide on two requests for the use of the Coronavac vaccine as well as the AstraZeneca vaccine from the University of Oxford.
Household expectations
The news could also potentially hamper China’s own coronavirus vaccination, Huang warned.
China has vaccinated tens of thousands of people with Sinovac’s vaccine since July under a government-approved emergency use program, which includes at least three Chinese vaccine candidates.
Chinese public health experts have repeatedly told the public that they are confident that Chinese vaccines are at least as good as, if not better, than foreign alternatives, Huang said.
“When people find out about this, they can question the safety and efficacy of the Sinovac vaccine or even other Chinese vaccines,” Huang said. “I think the government will have to work convincingly on those who have already taken the shots, or are on the verge of doing so.”