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by makomk 1766 days ago
Covid-19 vaccination used to reduce viral load of subsequent infections. Unfortunately, this doesn't seem to work with the current Delta variant - both the CDC in the US and PHE in the UK have released studies finding that the viral load of vaccinated and unvaccinated people is basically the same. They're also not so effective at stopping people from catching the Delta variant, and when you combine that with its higher infectivity it's basically impossible to get herd immunity using them.
4 comments

No this is extremely misleading, the misquote you are using applies only to breakthrough infections, but the vaccines themselves are highly effective at preventing infection and thus breakthrough infections are very rare in vaccinated individuals.

Should you happen to not mount a robust immune response despite being vaccinated then at that point you will have a viral load similar to an unvaccinated person, but the good news is even if this is the case you will still have much less severe disease outcomes than an unvaccinated person.

The vaccines are incredibly effective against all current variants.

>breakthrough infections are very rare in vaccinated individuals.

This is simply not true. In countries with accurate tracing like Singapore and Israel, it's apparent that the vaccinated aren't significantly less likely to get infected than the unvaccinated. Check figure 10 on https://www.moh.gov.sg/news-highlights/details/update-on-loc... ; the unvaccinated only make up around 10-20% of cases. They also only make up 10-20% of the population; if the unvaccinated were more likely to be infected, we'd expect them to constitute a larger proportion of infections.

There have been > 111k breakthrough infections in the US alone through the end of July. The CDC stopped tracking them unless they resulted in hospitalization or death, but we can still look at the data from the 35 states still tracking it.

It is fair to say that vaccination reduces the chance of infection. "Very rare", however, is not how I would characterize it.

https://www.bloomberg.com/news/articles/2021-07-30/cdc-scale...

Data from Israel suggests that efficacy may be much lower than initially believed, but still much better than nothing.

https://www.sciencemag.org/news/2021/08/grim-warning-israel-...

They are effective. The vaccine stops delta between 70 and 90% of the time (depending on which vaccine and which study you look at). The "impossible to get herd immunity" scenario is within the error bars, but I wouldn't state that as a fact. On the contrary, it looks like NYC just reached it's Delta peak 2 or 3 days ago. This strongly implies herd immunity is still possible, but we need to wait and see if the trend holds.
Round 13 of the Imperial College REACT-1 study did still indicate an average lower viral load(higher Ct values) in vaccinated individuals.
Even in the case of the delta variant vaccinated people who get infected are more likely to have reduced symptoms (if they have any noticeable symptoms at all). That means a lot less coughing up huge plumes of virus over great distances. Nothing is perfect, but in the end the vaccines increase your odds of not being infected while decreasing your odds of spreading the virus. Herd immunity may not be reached but we can drastically reduce deaths and serious illness. That's already a win for vaccines.