Sputnik V Vaccine Efficacy
Public data on Russia's Sputnik V vaccine. It is an adenovirus vaccine like AstraZeneca's. It produced a higher efficacy though either because of a higher dose or because it used two different adenovirus vectors to evade adenovirus vector immunity issues. AstraZeneca is doing a trial of having one dose of its vaccine with one dose of Sputnik V to see if this will boost the AstraZeneca vaccine efficacy.
Ukraine this past week banned use of Sputnik V in Ukraine, which I think is unfortunate. This appears to be a highly efficacious vaccine and Ukraine desperately needs coronavirus vaccine supply. I think it could have been a good opportunity for diplomatic exchange between the two countries. I don't think Ukraine has the luxury to ban vaccine supply given mass coronavirus vaccination likely won't happen till 2022 at current expectations.
Ukraine is participating with COVAX, so should get AstraZeneca's, Pfizer's, and J&J's in the coming months for the most vulnerable (Moderna I believe is still negotiating with COVAX). They also have struck a deal with China's Sinovac for their vaccine, though this vaccine appears to have rather low efficacy compared to the other vaccines. But they all seem to have good efficacy on severe disease.
UK Dosing Strategy
This appears to be the evidence that the UK government was relying on for their strategy of delaying the second dose of the AstraZeneca vaccine. 12 weeks delay was the sweet spot for vaccine efficacy. But beyond that vaccine efficacy fell. This shows the importance of gathering the data. I don't think many experts expected the vaccine efficacy of the single dose to fall after 12 weeks.
The second doses were pretty important for neutralizing antibodies in the mRNA vaccines. And they don't have the same vector immunity issues as the adenovirus vector vaccines. This probably has relevance to J&J's adenovirus vector vaccine though for their two dose trial arm.
