[pfg]

> You're going to have to dumb it down for me as to how this doesn't refer to spread.

Vaccinated index cases infecting others in the same household are only one scenario, and in that particular scenario, the study found no impact on spread. The study did find that vaccinated household members were less likely to be infected (SAR 25% vs. 38%) and that vaccinated cases had a faster rate of viral load decline - both of these findings (especially the first one) also relate to spread.

(It's arguably a bit surprising that the faster rate of viral load decline did not have an impact on the SAR for vaccinated index cases - one could make a (hopefully) reasonable hypothesis that this would matter more outside of household settings and thus still have an overall impact on spread, but that's not backed by any data from this study.)

There's also a world of difference between not "ignor[ing] the vaccinated population as a possible and relevant source of transmission" and saying that it doesn't stop spread to any significant degree. It's not binary.

[spurgu]

WHO is citing that study as well[0], seemingly drawing the same conclusion as I did:

> Prior to the emergence of the delta variant, it was reported that the risk of symptomatic cases in household contacts of vaccinated cases was about 50% lower than that among household contacts of unvaccinated cases(22). However, the impact of vaccination on reducing transmission in the context of the more transmissible delta variant appears to be lower(23).

https://www.who.int/news/item/24-11-2021-interim-statement-o...

[0] The first link I posted, reference 23 in the WHO statement

[pfg]

I'm really not sure if we're on the same page on the conclusion of the study, so I'll repeat it just in case:

Scenario 1: A vaccinated household member (the index case) is COVID-positive. The study finds that other household members are just as likely to get infected regardless of the vaccination status of the index case. There is no reduction of spread.

Scenario 2: Some household member (regardless of vaccination status) is COVID-positive. The study finds that other vaccinated household members are less likely to get infected. Spread is reduced.

That's basically what the WHO is saying - we may have had the positive impact of scenario 1 prior to Delta, but that's mostly gone. Scenario 2 still shows some effect on spread. It may be lower now, but it's still significant.

The article also states that "Vaccinating school-aged children may help minimize school disruptions by reducing the number of infections at school" and "there are benefits of vaccinating children and adolescents that go beyond the direct health benefits. Vaccination that decreases COVID transmission in this age group may reduce transmission from children and adolescents to older adults".