Intramuscular/serum vaccines cannot stop respiratory infections, by definition. They are non-sterilizing. Only a nasal/mucosal vaccine or nasal infection can provide sterilizing immunity against a respiratory virus.
This is the technological limits of what vaccines are capable of. Vaccination limits the damage, ensuring a much lower likelihood of catching a 1 to 3 day cold affecting only my upper respiratory tracts rather than risking the lungs and the rest of my body on a potentially multi-week infection.
The longer the infection, the more likely pneumonia or another co-infection will injure or kill you.
https://www.cdc.gov/flu/prevent/flushot.htm
So does the Mayo Clinic:
https://www.cdc.gov/flu/prevent/flushot.htm
I won't go on, but by definition, a medicine that you take that's intended to build up your immune response to a disease is a vaccine. I saw someone upstream write "Intramuscular/serum vaccines cannot stop respiratory infections, by definition," and as far as I can tell this is just point-blank wrong. Whooping Cough -- pertussis -- is a respiratory bacterial infection we've been vaccinating against with intramuscular shots since the 1940s.
Does measles count as a respiratory infection? It causes coughing, is airborne, and infection happens via nasal passages. The intramuscular measles vaccine seems to work pretty well.
Is it super important that they are technically wrong on something, anyway? Like, do you think Fauci is going to be cancelled because he said something wrong? I doubt that's going to occur based on his prior messaging.
"If you're vaccinated, you won't get COVID" - Joe Biden
From the beginning, there has not been a COVID-19 vaccine that purported to be 100% effective. There are vanishingly few vaccines that provide 100% immunity, if for no other reason than the immune system is not perfect.
In human history, we have only completely removed 1 virus from humanity: smallpox. That is literally the only 100% effective vaccine ever produced. And even then, it is only 100% effective after the fact.