A majority of the vaccine doses used in Seychelles is the Sinopharm. It uses a human adenovirus as its viral vector. One aspect that was mentioned early last ye

A majority of the vaccine doses used in Seychelles is the Sinopharm. It uses a human adenovirus as its viral vector. One aspect that was mentioned early last year in Derek Lowe's roundup is that most Asians have existing antibodies against this adenovirus type (for Indians, I believe the figure is around 80%). That may be why this vaccine may not be adequately effective in certain populations.