Do you have a linkable source for that? I tried a Google search and found an article sayingSinovac and Sinpharm vaccines need 1-2 months after the second shot to start working. Otherwise, they are relatively safe and effective.
Based on that language I suspect they merely tested for antibodies 2 months after the second shot, not weekly to see more precisely when the antibody count climbed. That article is nearly 4 months old, perhaps there is newer data or data they missed when writing that article?"Current figures show that the protection rate of Sinovac vaccines within two months after administering two shots is 80-90 percent, but the number of antibodies in recipients declines with time."
