Other countries are discovering that certain vaccines may not be as effective as others in preventing infections caused by these variants. …
Dr. Adib said that the association is now discussing the possibility of administering to medical workers a third shot of another vaccine, such as Oxford-AstraZeneca. Some countries are supporting a mix-and-match scheme to boost immunity. Sinovac, which is produced by a Chinese pharmaceutical company and promoted by the Chinese government, has been criticized for a lack of transparency about its clinical trials.
