From Roxanne Liu and Anthony Boadle
BEIJING / SAO PAULO (Reuters) – An experimental coronavirus vaccine developed by China’s Sinovac Biotech appears to be safe in a late clinical trial in Brazil, preliminary results showed on Monday.
The Butantan Institute in Sao Paulo, one of Brazil’s leading biomedical research centers that conducts Phase 3 tests, said the two-dose vaccine, called CoronaVac, has been shown to be safe in a study of 9,000 volunteers so far.
But Bhutan director Dimas Covas said the vaccine’s effectiveness data would not be published until the trial of all 1
“The first results of a clinical study conducted in Brazil prove that of all the vaccines tested in the country, CoronaVac is the safest, with the best and most promising rates,” Sao Paulo Governor Joao Doria told reporters.
The result is only preliminary and researchers will continue to monitor participants in the ongoing process, Covas said. This is the first set of results from Sinovac’s Phase 3 global trials, which are also being conducted in Turkey and Indonesia.
Covas said there were no serious side effects to the vaccine, with 20% of volunteers reporting mild pain from the injection, while 15% reported headaches after the first dose, falling to 10% for the second. Less than 5% reported nausea or fatigue, and even fewer had muscle pain, he said.
Sao Paulo’s state health minister, Jean Gorinchtein, said the vaccine appeared to produce protective antibodies. The state hopes to receive regulatory approval for CoronaVac by the end of the year to begin inoculating its population in early 2021, as part of America’s first vaccination programs.
Sao Paulo signed a contract with Sinovac to purchase 60 million doses by the end of February.
Sinovac wants Brazil as a testing ground because it is one of the world’s outbreaks of the virus, although the cases are 43% lower than the peak of nearly 70,000 new cases a day at the end of July.
Since the beginning of the pandemic, Brazil has reported more than 5.2 million cases of COVID-19, the third most affected country in the world after the United States and India.
AstraZeneca PLC and the University of Oxford are approaching the analysis of their study on a coronavirus vaccine in the UK. Pfizer Inc said it could provide an early analysis of its trial this month, and Moderna Inc could announce its results in November. Russia’s Gamaleya Institute may submit an analysis of its vaccine next month.
Competing candidates developed by AstraZeneca and Johnson & Johnson have stopped testing in the United States due to safety concerns.
Vaccines are considered the main tools to curb the rampant virus that has killed more than 1 million people worldwide. Brazil is also hosting the AstraZeneca Phase 3 vaccine candidate, while Johnson & Johnson said last month it aims to expand its final human trials there.
CoronaVac uses inactivated vaccine technology, a traditional method that uses a killed virus that cannot replicate in human cells to elicit an immune response.
Experts warn that the safety of inactivated candidates for coronavirus vaccination should be monitored for longer periods, as some other inactivated vaccines have led to a disease-enhancing effect, where vaccine-induced antibodies, instead of offering protection, can exacerbate infections when people are exposed to the virus after inoculation.
(Report by Roxanne Liu and Anthony Boadle; Additional reporting by Eduardo Simoes in Sao Paulo; Edited by Miyoung Kim, Christian Plumb and Leslie Adler)