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With trials of Sinovac Biotech Ltd.’s coronavirus vaccine in Brazil and Turkey suggests that the injection has a protection rate on both sides of 90%, there is still no final assessment on how effective it is exactly in protecting people against Covid -19.
Sinovac is finalizing the results of phase III trials carried out in Brazil, Turkey, Indonesia and Chile, according to a person familiar with the trials. Those tests are relatively independent of each other and performed according to different protocols, rather than being subject to unified rules that generally govern such tests, said the person, who asked not to be identified because the data is not public.
Researchers in Brazil earlier this week delayed the release of full information on the Sinovac vaccine, saying only that it was found to be more than 50% effective. Sao Paulo state health secretary Jean Gorinchteyn offered more specific guidance on Thursday, saying the vaccine “did not reach 90%” efficacy, which would make it less successful than those developed by Pfizer Inc. and Moderna Inc.
“We do not know how much more than 50% it was, if it was 60%, 70% or 80%, but it is at levels that allow us to reduce the impact of the disease on our population,” Gorinchteyn said in an interview with CBN Radio in Brazil. “We knew that the effectiveness would never reach 90%.”
Turkey test
To add to the confusion, Turkey He said a trial of the Sinovac vaccine that took place in his country showed an estimated efficacy rate of 91.25%. That trial, however, is based on just 29 cases, which is deemed insufficient to draw a definitive conclusion about the effectiveness of the shot, according to the person familiar with the trials. The trial will continue to collect Covid-19 cases for a more final reading, the person said.
A spokesperson for Sinovac declined to comment on questions about the vaccine’s effectiveness.
The delay in announcing the final results has created confusion about the effectiveness of the Sinovac shot. Chinese developers have been slow compared to their Western peers in publishing efficacy data, risking an erosion of trust in these candidates as the world turns a laser focus on which vaccines are most successful in fighting the pandemic.
Meanwhile, Pfizer and Moderna injections have been shown to reduce symptomatic cases by more than 90%.
China race for COVID-19The -19 vaccine raises safety issues
The reason Brazil has yet to reveal full efficacy figures is because Sinovac and its partners are reviewing all Covid-19 cases found among the participants, the person said. Brazil’s trial has yielded more than 170 cases, but Sinovac needs to verify them to see if they all meet the criteria set by the Chinese drug regulator.
Regulators in China and Brazil, as well as Sinovac and its partners are still in the process of analyzing data from the Brazil trial, according to the person. Ultimately, Sinovac hopes to see unified standards to ensure equal comparisons across different test sites, the person said. The protocol for the Brazil trial says that Covid-19 cases are diagnosed according to the guidelines of the US Food and Drug Administration.
The late-stage trial of the Sinovac vaccine in Brazil, which involved approximately 13,000 participants suggested the vaccine is “safe and effective,” authorities from the Butantan Institute and the state of Sao Paulo said earlier in the week.
Saving lives
Sinovac is betting on a successful vaccine to inoculate more people around the world and save lives, especially in developing countries like Brazil, which will have limited access to Pfizer and Moderna vaccines. Sinovac injection is potentially more suitable for developing countries because it can be kept at normal refrigerator temperatures, while Pfizer and Moderna vaccines require deep freezing conditions for storage and transport.
The Sinovac vaccine has been at the center of a political dispute between Sao Paulo Governor Joao Doria and President Jair Bolsonaro, who says a vaccine from China cannot be trusted. Bolsonaro once again questioned the effectiveness of the Sinovac vaccine in a Christmas Eve speech broadcast on Facebook.
“I want to make it very clear that the label on this vaccine will be ‘we are not responsible for any side effects.’ The responsibility is yours, ”he said.
– With the assistance of Andrew Rosati and Dong Lyu
