SÃO PAULO—Brazil’s health authority said it has serious doubts about the safety and efficacy of Russia’s Sputnik V Covid-19 vaccine and defended its decision to block the shot for emergency use, saying Russia lacks vaccine experience and was defensive in its responses to the agency.
The agency, Anvisa, declined to approve the vaccine last week despite a shortage of Covid-19 shots in the hard-hit country and a Sputnik V rollout in more than 60 countries that have already approved the vaccine for use.
Brazil is concerned the vaccine could contain active adenovirus particles, responsible for the common cold, which could make recipients sick, said Gustavo Mendes, Anvisa’s medicines and biological products manager, in an interview Monday.
Mr. Mendes said Brazil also had doubts about the methodology used in Sputnik V’s clinical trials and whether the batch of doses that Brazil would receive would be identical to the shots tested in those trials.
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