Question: I was just reading that Russia’s Sputnik vaccine is highly effective. What do we know about it?
Answer: Like you, I read yesterday’s news, which reported Sputnik V’s lead scientist recently presented findings to the Russian Academy of Sciences showing the vaccine is 97.6% effective based on a real-world analysis of data from 3.8 million people who had received both doses. That’s even higher than the 91.6% efficacy reported in Sputnik’s phase 3 clinical trial interim results. Despite these very promising results, the vaccine has remained contentious.
How does it work? The Sputnik V vaccine is similar to other vaccines (e.g. J&J and AstraZeneca) in that it is a viral-vector type vaccine (for refresh on vaccine types, see Q&A of 1/21). What’s unusual about Sputnik V is that it uses not one, but two harmless common cold viruses, adenovirus vectors (rAd26 and rAd5) delivered separately in a first and second dose, 21 days apart. Combined with the SARS-CoV-2 spike protein, this viral vector vaccine prompts the body to make an immune response against COVID. Analysis of safety and efficacy from phase 1 and 2 clinical trials was published in Lancet in September 2020 and analysis of phase 3 clinical trial interim results was published in Lancet in February 2021. These analyses indicate that the vaccine is safe and effective. Sputnik V is, however, contentious.
Why contentious? Here are several reasons the vaccine remains contentious (note: this list is not exhaustive): First, Russia’s President Putin approved the vaccine (developed and manufactured in Russia) in August 2020, before phase 3 clinical trials had started. This was a major breach of ethics, casting doubt on the scientific process and on the vaccine developer’s ability to deliver any results but positive results. Second, heavy and seemingly coercive pressure for some Russians to join the clinical trials, as reported in Reuters, cast further doubt on the study’s human subjects protections and ethical merits. Third, results published from the phase 1 and 2 clinical trials had some suspicious elements– the data presented showed unlikely coincidences (e.g. participants all had identical levels of T-cells) that suggested data manipulation to some scientists. Sputnik V developers refuted these suspicions in a response published in Lancet in September 2020. And phase 3 results have further ameliorated scientific concerns. To my knowledge, primary clinical trial data (the kind FDA reviews for emergency use authorization) have not been made available to independent authorities, which has reduced transparency and limited trust. Add to this geo-poliitical tensions, and it’s easy to see why the vaccine has been fraught. Even so, at least 60 countries have authorized the use of Sputnik V, with India having granted emergency use authorization just last week (Figure 1).
Figure 1. Map of countries that have approved Sputnik V (from DW.com)
