Covid-19 vaccines cannot be ranked as they are not tested one against the other. As per WHO, a Covid vaccine can be approved if it demonstrates >50% efficacy in preventing Covid illness. Hence, all approved vaccines satisfy the above criteria. Efficacy may be expressed in terms of inducing antibodies, preventing infection, any illness, moderate to severe illness, and death. Efficacy also varies as per the dominant circulating variant. Hence, every approved vaccine is effective in preventing Covid illness, especially of moderate to severe illness.
admin Answered question August 27, 2021