Good point, but you would have to ask the same with Pfizer, Modena, and any others in relation to the new American strain which is supposedly even more contagious.It is also worth noting the alarm the new Brazilian variant of Covid is causing in governments around the world, with many nations banning flights from Brazil.
It is interesting that no one in the media is making the blindingly obvious connection and asking if the Sinovac results might have been skewed by the much more potent Brazilian variant.
Although the plus side is that the Sinovac vaccine would appear to be clinically proven to be effective against the new Brazilian strain in so far as preventing deaths and serious illness at a minimum.