Against the original strain, Pfizer had around 95% efficacy. But it is proving increasingly ineffective against the delta variant, which is causing a majority of the COVID-related deaths now. Check this:
https://www.reuters.com/business/healthcare-pharmaceuticals/moderna-may-be-superior-pfizer-against-delta-breakthrough-odds-rise-with-time-2021-08-09/
A study by the Mayo Clinic suggests that Moderna vaccine is 76% effective against the delta variant, while Pfizer has an efficacy of just 42%. BTW, the other vaccines (such as Sinopharm and AstraZeneca) fare far worse against the delta variant.
I hope you are kidding? Why would I read these childish excuses like "the
The virus mutates all the time and a vaccine that works well against one strain is rubbish. And by killing one strain, you immediately open the way for all others who were "oppressed" by the more widespread strain. It's an endless loop. By the way, do you think that in the future you will have to do a thousand vaccinations against each strain separately?