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Making Sense of the Spat Between Anvisa and Gamaleya Over Sputnik V Vaccines

Making Sense of the Spat Between Anvisa and Gamaleya Over Sputnik V Vaccines

A nurse prepares a dose of Sputnik V vaccine at a clinic in Moscow, Russia September 17, 2020. Photo: Reuters/Tatyana Makeyeva

A dispute has broken out over Russia’s Gamaleya Institute and Anvisa, Brazil’s national drug regulator.

The trigger was that Anvisa had said that Brazilian authorities wouldn’t be allowed to import Sputnik V, the COVID-19 vaccine made by the Gamaleya Institute. In response, the Gamaleya Institute has denied Anvisa’s claims and has threatened a lawsuit.

The problem, according to Anvisa, is that doses of the Sputnik V vaccine may contain adenoviruses that are able to replicate (make copies of themselves).

The Sputnik V vaccine uses two adenoviruses, called Ad5 and Ad26, to transport genetic instructions to make the novel coronavirus’s spike proteins.

The vaccine is made by inserting these instructions into the adenoviruses and injecting the adenoviruses into the human body. Inside the body, the viruses ‘swim’ to cells, which read the instructions and make the spike protein. The immune system takes notice and starts the immune response.

Science explained that the gene that adenoviruses need to replicate themselves is called E1. Researchers first remove the E1 gene from the adenoviruses and insert them into the HEK293 cells.

The HEK293 have a “stand in” E1 gene that allows the adenoviruses to replicate. The adenoviruses are then removed from the HEK293 cells and packaged as the vaccine.

As such, once they are injected into the human, the adenoviruses shouldn’t be able to replicate.

Anvisa said that it had found adenoviruses that are able to replicate in some doses of the Sputnik V vaccine.

Some Ad5 adenoviruses are supposed to be able to copy the E1 gene from the HEK293 cells and develop the ability to replicate, although it’s not clear if that’s what happened here.

When pushed, Anvisa added that it came to this conclusion not by testing the vaccine itself but based on data that Gamaleya had shared.

Gamaleya has said Anvisa’s allegation has “no scientific grounds”.

For now, there is no consensus among scientists not affiliated with either body, although some have defended Anvisa’s comment and some others are skeptical. Those in favour of Anvisa’s conclusion have also pointed to the fact that Gamaleya didn’t share safety data from clinical trials of Sputnik V for a long time, and that Russia has floated a lot of misleading propaganda to promote the vaccine.

Sputnik V was found to have an efficacy of 91.6% in the trials.

Those who aren’t convinced by Anvisa’s conclusion have said Anvisa may have misinterpreted the data that Gamaleya shared.

According to Science, Anvisa displayed quality control documents it has received that reportedly say the batches Anvisa sampled had “‘less than 100’ replication-capable particles per dose.” Whether this means zero or some positive number is unclear. Anvisa has said its limit is zero.

A senior official from Anvisa also reportedly disclosed bits of an online meeting between officials of Anvisa and Gamaleya. In this meeting, when asked why Gamaleya hadn’t changed their manufacturing protocols given there are replication-capable particles in some of the doses, Gamaleya officials reportedly said doing so “would take too much time”.

The dispute is yet to be settled.

Anvisa has also complained that its officers weren’t allowed to more than half of the seven manufacturing facilities making Sputnik V, including a quality control centre. The regulator has also asked for more data about 63 adverse events that had been reported during Sputnik V’s clinical trials. But in its statement, Gamaleya said Anvisa officials had “full access to all the relevant documents as well as to research and production sites.”

A former science minister of Brazil, Sergio Rezende, told Science that state governors of Brazil have sent new documents from Gamaleya to Anvisa, hoping to change the latter’s mind.

Brazilian authorities have been hoping that Sputnik V can join the country’s repertoire of vaccines and help ameliorate its raging COVID-19 crisis.

The situation is the same in India, which has reported more than 3 lakh new cases a day for 12 days in a row. Recently, after a vaccine shortage that the government had been denying became apparent, Prime Minister Narendra Modi invited foreign vaccine-makers to apply for approval and sale in India.

After Covaxin and Covishield, the Sputnik V vaccine was the third approved for use in India. The first consignment of 1.5 lakh doses landed in India on May 1.

Earlier, Anvisa had also rejected Bharat Biotech’s application for Brazil to import Covaxin. The allegation there was that the process Bharat Biotech was using at its Indian manufacturing facilities to inactivate the novel coronavirus, before packaging viral particles into the vaccine, hadn’t been validated properly.

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