(Reuters) --- The director of Chile’s health regulator said he sees no evidence of safety issues with Sputnik V, the COVID-19 vaccine developed in Russia, despite its rejection by the Brazilian health regulator this week over a lack of information about its safety.
Heriberto Garcia, the director of Chile's Public Health Institute (ISP), said Chile was seeking clarity from the vaccine's developers about the potential presence of an adenovirus that could reproduce, possibly creating a negative reaction in recipients. This was the basis for Brazil's health regulator, Anvisa, rejecting the vaccine on Monday.
But he added that real-world data from Argentina and Mexico, where Sputnik V is already being rolled out, showed instances of significant effects among recipients of the vaccine were no greater than those among Chilean citizens who have received the Pfizer-BioNTech (PFE.N), (22UAy.DE) or Sinovac (SVA.O) equivalents.
He said that even if Sputnik V's developers supplied information suggesting the presence of "replication-competent adenoviruses" (RCA), the ISP would not necessarily reject it.
"We have to balance the benefit of getting vaccinated versus not getting vaccinated," he told Reuters in a Zoom interview. "If the virus replicates, you're going to get at most a common cold. If you don't get vaccinated, you could get COVID-19."
Adenoviruses - a category of viruses that can cause a range of illnesses in humans like the common cold - are sometimes repurposed as viral vectors for vaccines. However, global health guidelines warn against "replication-competent adenoviruses" that could multiply inside a patient's body, possibly creating a negative reaction.
Chile is in the final stages of negotiating a deal to buy 4 million doses of Sputnik V as it races to vaccinate 80% of its target population - 15 million people - by July.
Moscow's Gamaleya Institute which developed Sputnik V said in a statement to Reuters on Friday that no RCA was detected in any of the batches of the Sputnik V vaccine.
Anvisa's five-strong board voted unanimously not to approve the Russian vaccine, saying it had identified "inherent risks" and "serious" defects, and cited a lack of information guaranteeing its safety, quality and effectiveness.
The Russian Direct Investment Fund (RDIF), which markets the Sputnik V vaccine abroad, has rejected Anvisa's comments, saying the shot's safety and efficacy had been assessed by regulators in 61 countries which approved it for use.
The Gamaleya Institute has said Sputnik V is 97.6% effective against COVID-19 in a "real-world" assessment based on data from 3.8 million people.
The European Union's regulator, the European Medicines Agency (EMA), is evaluating the shot and its manufacturing process, with a decision on its use expected in May or June.
The ISP's Garcia said discussions with RDIF had begun a month ago and were "100% positive" so far.
He said he was confident RDIF could supply the extra documentation the ISP had asked for before it began considering Sputnik V for approval for emergency rollout.
"I doubt that there is a problem but we as a regulator need that information so we as a health authority can reassure our population," he said.
He said Brazil's rejection of Sputnik V over missing documentation was "valid" but that the ISP would avoid a similar issue by insisting on all the necessary documentation about Sputnik V before formally considering it for use in Chile.
"This avoids generating mistrust about vaccines which won't get us anywhere," he said.
RDIF has claimed that Anvisa could have been "politically motivated" to reject Sputnik V. Garcia said there could be no similar claim toward Chile.
"The pressure that I have, that we all have, is to end this pandemic soon and for that we know that vaccines are a good tool," he said. "So we are doing everything possible to have as many vaccines as possible and balance the risks with the benefits."
