Side-effect questions
Sputnik’s side effects are also becoming clearer; studies so far suggest that they are similar to those of the other adenovirus vaccines, with the notable exception of rare blood-clotting conditions. Unlike for both the Oxford–AstraZeneca and Johnson & Johnson vaccines, there have been no reports of these disorders from Russian health authorities or from the other nations using Sputnik V.
A preprint3 from the Italian Hospital of Buenos Aires in Argentina reported no cases of clotting disorders or adverse events of special interest among 683 health-care workers vaccinated with Sputnik V. And an analysis of 2.8 million doses of Sputnik V administered in Argentina reported no deaths associated with vaccination, and mostly mild adverse events. Furthermore, a study posted as a preprint in May, from the republic of San Marino, found no serious adverse events in 2,558 adults who received one dose of Sputnik V and 1,288 who received two doses4.
Virologist Alyson Kelvin at Dalhousie University in Halifax, Canada, says there is a theory that the clotting disorder is associated with viral-vector vaccines, but adds, “I don’t think we have exact causation of what component of those vaccines are causing it”, or whether Sputnik might also be affected. She notes that although the phase III study of Sputnik V enrolled only 21,977 people, and thus was too small to pick up rare adverse events, the vaccine is now in widespread use globally, which means that reports should appear “if a safety signal comes up”.
It is not clear whether Russia is in a position to detect such rare events. Those associated with the Oxford–AstraZeneca vaccine first came to light through adverse-event monitoring in Austria, which prompted the EMA to review the vaccine’s safety.
But Russia’s adverse-event monitoring might be less effective, Kulish argues, partly because of a cultural resistance to seeking medical care. “Most Russian people will call [the] doctor only when they cannot breathe any more,” he quips. Furthermore, doctors in remote regions of Russia might not connect a stroke caused by blood clots, for example, to a recent vaccination, he says.
Argentina has not reported any clotting events, despite receiving more than four million doses of the vaccine, Kulish notes. Serbia, which has also been using Sputnik V widely, has so far reported no cases of the blood-clotting condition reported with other adenovirus vaccines.
https://www.nature.com/articles/d41586-021-01813-2
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