Around October 11nth, Pfizer executive Janine Small testified to the EU parliament that Pfizer did not test the vaccine for preventing transmission of Covid prior to it being made available to the public. This was not actually a requirement for the Emergency Use Authorization. They only had to show that it was safe and that it prevented people from getting the disease. She explained that they did not have time to test for how the vaccine would affect transmissibility. Additional studies would eventually come out showing that the vaccine reduced the transmission of the disease. (https://www.nejm.org/doi/full/10.1056/nejmoa2116597)
The anti-vaxers and the conspiracy theorists took this "admission" and ran with it. People I listen to on a regular basis started claiming that Pfizer admitted that the vaccine does not prevent transmission of the disease and that the government officials lied to us about it. Some even claimed that the vaccine doesn't work, or that it was never tested.https://fullfact.org/health/coronavirus-vaccine-pfizer-transmission-test/
However, none of these statements logically follow from the testimony of Janine Small. The initial vaccine was 95% effective against the wild-type SARS-CoV-2. If you reduce the infection rate then it is very likely that you also would reduce transmission of the disease. It is possible for someone who is asymptomatic to transmit the disease, but would you rather hang out with someone who has full-blown COVID, or someone who is asymptomatic and has been vaccinated?
These kinds of errors in logic also have led to claims that the vaccine didn't work against the Omicron variation or that masks don't work. A May 2022 study published in the New England Journal of Medicine showed that the booster shot was 49% effective against the Omicron variant. For me, that was better than nothing, and the new bivalent booster is more effective. (https://www.nejm.org/doi/full/10.1056/NEJMoa2208343
A study published in the Yale Medical Library Journal July 28, 2022 found that those wearing masks only had a 7% infection rate while those who didn't wear masks had a 52% infection rate.
Despite actual evidence suggesting otherwise, those who criticize the vaccines or masks often claim that they are following the science.