SÃO PAULO—Brazil’s health authority, Anvisa, said it has serious doubts about Sputnik V’s safety and efficacy and defended its decision to block the Covid-19 shot for emergency use, saying Russia lacks vaccine experience and was defensive in its responses to the agency.
Anvisa’s decision last week, despite a dire shortage of Covid-19 vaccines in the hard-hit country, caused consternation world-wide, where more than 60 countries have already approved Sputnik for use.
Anvisa’s medicines and biological products manager Gustavo Mendes said in an interview Monday that Brazil is concerned the vaccine could contain active adenovirus particles, responsible for the common cold, which could make recipients sick.
Mr. Mendes said Brazil also had doubts about the methodology used in Sputnik’s clinical trials and whether the batch of doses that Brazil would receive would be identical to the shots tested in those trials.
“It’s a question of both safety and efficacy,” said Mr. Mendes, saying that Anvisa had faced intense pressure from the public to approve the shot, with more than 2,000 people dying a day from the disease in Brazil.
“They say to us ‘People are dying, these vaccines could save lives,’ but with the amount of questions and doubts we have, it’s not clear that this vaccine really will give protection,” Mr. Mendes said.
Both Chile and Colombia have sought further information from Brazil on Sputnik’s possible problems after Anvisa’s ruling last week, he said.
Anvisa could still approve the shot if its maker, Russia’s state-owned Gamaleya Research Institute, provides more information to prove the vaccine’s safety and efficacy, or adjusts its manufacturing process, Mr. Mendes said.
The Russian Direct Investment Fund, which manages the foreign sales of the shot, didn’t immediately respond to a request for comment. The Russians have previously rejected Brazil’s concerns, accusing Anvisa of acting politically at the behest of Washington to discredit the vaccine.
—Georgi Kantchev in Burgas, Bulgaria, contributed to this article.
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