I wonder if a covid shot that went through a full testing sequence would have done better?
but now we know why the breakthrough rate for injected vaccinated is so high https://www.nature.com/articles/s41385-022-00517-8
in short, nasal vaccination that actually trains the mucosal immune system has the potential to actually prevent infections, as the mucosal immune system is the first line of defense. the intramuscular shots have no chance to prevent infection.
i can see benefits to touting 94+% efficacy for the intramuscular vaccines (with the fine print that efficacy is only measuring reduction of severe infection), because it does help prevent hospitalizations and deaths. i think it would be difficult to convince a population to vaccinate while saying it doesn't prevent infection.
The dose optimization curve of mRNA vaccines had the ideal effect happening at about 1/2 for people over 65 of the production vaccine, all the way to 1/5 for kids. Meaning they were giving 2-5x too much for what was needed to achieve the intended effect.
The intramuscular vaccines did prevent infection in about 94-95% of cases though, as the article you link mentions in the section “Efficacy and effectiveness of SARS-CoV-2 vaccines”: “According to multiple case-control studies, BNT162b2 (BioNTech/Pfizer) has a real-world efficacy of 94–96% against symptomatic infection after two doses16 and 86–92% against any infection after two doses”.
These studies are no longer valid due to the emergence and spread of the Omicron variant which the vaccines were not tested against and do not work to prevent infection.
I was a participant in a phase 1 study for a nasal vaccine in 2021. Unfortunately the trial failed so much that it was ended early, as it didn’t generate the needed antibodies. Nasal vaccines are an interesting area of study but the technology to provide them does not seem to be fully there yet (I think FluMist was the only one before COVID, and it actually was worse than the intramuscular flu vaccine sometimes.)
Maybe, but it would have been too late.
The current vaccine is not perfect, but it did one thing very well: it seriously limited the damage done by the deadly Delta variant. Omicron and other immunity-evading variants would have come eventually, but thanks to the vaccine, it did so with less dead people along the way.
Had it come a year later, it would have been useless in that role. And now that we are apparently done with the pandemic phase, we have a bit more time for more thorough research and better long-term testing.