Please see the links below.

https://www.bbc.com/news/health-54902908

https://www.nytimes.com/2020/12/15/health/covid-moderna-vaccine.html

In my opinion, it is too early to determine the efficacy of those vaccines in the real-world setting, as we have seen new variants of SARS-CoV-2 virus coming (B.1.1.7 variant and others). Some molecular immunology experts have predicted that the occurrence of antigenic drift event for SARS-CoV-2 will be possible, and it remains to be seen. I give you one example about the yearly update of influenza vaccines due to the constant antigenic drift of the flu virus.

NO body can guess which of those is more effective. Moreover, such viruses are highly polymorphic, which means the vaccine is not for all genotypes.

Thank you for your all answers

Please see the links below.

https://www.bbc.com/news/health-54902908

https://www.nytimes.com/2020/12/15/health/covid-moderna-vaccine.html

Dear Djemli Samir, you may look through the link below:

https://english.jagran.com/world/coronavirus-vaccine-updates-from-pfizer-to-moderna-to-sputnik-a-look-at-major-covid-vaccine-candidates-and-their-status-10022158

Concerning the new SARS-CoV-2 variants, I think the Pfizer and Moderna vaccines are still effective (for now). But I am still worried, because if the virus continuously gets transmitted due to lack of social distancing and vaccine hesitancy / phobia...this may give the virus ample chance to mutate leading to antigenic drift or even to the potentially worrisome antigenic shift. If the accumulated mutation becomes too enormous and diverse, the vaccines at present might no longer work. This is indeed a ticking time bomb and the challenge now is to vaccinate as many people as possible to confer herd immunity.