Anecdotally and by coincidence this morning I was talking to friends here. Their family has all be vaccinated, parents one with Sputnik (1 dose), other with Sinopharm (2 doses). Other person with Pfizer (2 doses). All received last dose at least 6 weeks ago. They all had private lab antibody tests done and were surprised that the person with Sinopharm had less than half the antibodies of either person with Sputnik or Pfizer, who both were found to have “high” levels of antibodies. That would suggest that out of these people the one with the Sinopharm would have the highest risk of getting infected, infecting others or getting seriously ill from the virus.
It’s still early days for any vaccine or vaccine program so best to be open minded about how data will evolve with time. For example, now some studies are even suggesting it’s actually beneficial to mix and match vaccines instead of getting two doses of the same in order to get higher levels of immunity. Other studies give a magic number of 75% of a population fully vaccinated to be able to overcome the pandemic and not need to worry too much about subsequent hospitalizations and deaths in both the vaccinated and unvaccinated population.
Also countries like Israel that are down to double digit daily cases or a 7 day average deaths of 1 are interesting to watch at this moment as since May Israelis have been traveling quite freely. Presumably this means they are coming into contact with various strains in Europe and elsewhere then returning home to a country where 40% of the population are still unvaccinated.