Is taking three sinopharm covid vaccine doses equal in efficacy to two pfizer doses ? how long after the third sinopharm can someone take another vaccine ?

I do not know of studies that address this issue. I would go to pubmed.gov and search for sinopharm immunization for COVID-19 AND Pfizer COVID-19 and you can see the worlds literature, read, share with local experts and decide. just be certain you get the vaccination they recommend and have where you live.

The Pfizer vaccine has a 94% relative success rate. The "sinopharm covid vaccine" has at best a 79% success rate, and uses an inactivated virus. Although CDC has no problems with booster shot being any of the 3 USA approved vaccines, am unable to comment on a non approved vaccine.