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The argument that vaccines don't prevent delta tranmission are based on headlines, not science. And unfortunately right now science is playing catch-up. There

The argument that vaccines don't prevent delta tranmission are based on headlines, not science. And unfortunately right now science is playing catch-up. There simply isn't any evidence on breakthrough transmission with delta testing humans yet because it is recent. The headlines and public health messages are assuming worst case in order to scare vaccinated people into masking up again, while there's actually indications that vaccinated breakthrough infections almost certainly transmit less. What we know is that while early in the infection viral loads in delta are much higher, but Alpha, delta, and non-VOI/VOC infections feature similar viral trajectories[1], in vaccinated breakthrough infections RNA load declines faster[2] and the ability to culture virus in breakthrough infections is lower[3], we know that vaccines reduced transmission with alpha[4] and apart from scary headlines we still expect that vaccines reduce transmission with delta. While there's documented cases of delta breakthrough infections transmitting to one or two other people, there's not been any studies of how common that is, or how common it is for breakthrough infections to become superspreaders to >10 people, or if that is even possible. Since viral loads are correlated with transmissibility and symptomology/virulence the very high protection against severe disease with vaccination may also protect against severe transmission. [1] https://www.medrxiv.org/content/10.1101/2021.02.16.21251535v3 https://www.medrxiv.org/content/10.1101/2021.02.16.21251535v... [2] https://www.medrxiv.org/content/10.1101/2021.07.28.21261295v1.full.pdf https://www.medrxiv.org/content/10.1101/2021.07.28.21261295v... [3] https://www.medrxiv.org/content/10.1101/2021.08.20.21262158v1 https://www.medrxiv.org/content/10.1101/2021.08.20.21262158v... [4] https://www.timesofisrael.com/80-of-vaccinated-covid-carriers-didnt-spread-virus-in-public-spaces-report/ https://www.timesofisrael.com/80-of-vaccinated-covid-carrier...

mythrwy 5y ago
`The argument that vaccines don't prevent delta tranmission are based on headlines, not science.` That is not the case. https://www.nature.com/articles/d41586-021-02187-1 https://www.nature.com/articles/d41586-021-02187-1 "“The bottom line is, this can happen — it can be true that vaccinated people can spread the virus. But we do not yet know what their relative role in overall community spread is,” says co-author Thomas Friedrich, a virologist at the University of Wisconsin–Madison." Vaccinations may (or may not) reduce the propensity of vaccinated people to spread Delta but it's very clear at this point vaccinated people can spread Delta to some degree.
- lamontcg 5y ago
  I'll help you out, here's a documented case of transmission from one breakthrough infection to another breakthrough infection to two more: https://wwwnc.cdc.gov/eid/article/27/12/21-1792_article https://wwwnc.cdc.gov/eid/article/27/12/21-1792_article It is 100% certain that some breakthrough transmissions can transmit onwards. If I know that, it should be very apparent that wasn't what I meant. There are people claiming that vaccines do not prevent any forwards transmission and that vaccination is 100% worthless for ending pandemic spread. Arguing that is wrong does not imply arguing for the exact inverse and that vaccines are perfect. I'm pretty sure that hell is the world where everyone argues in absolutes all the time and that I'm unfortunately living in it.
blagie 5y ago
sigh All of this is irrelevant to the central point. The article fabricated facts. If you're a scientist, your conclusion can be 100% and you're still a fraud if you've baked data to get to that conclusion. As a footnote, we do have data. My best estimate was that the vaccine reduced the transmission of delta by about 50%. That's based on data in the community I live (and this is context-dependent -- for example, vaccines do a lot more for casual interactions than for close/long ones). I saw that same estimate replicated by two data scientists I trust, using different data from different places, and different methodologies, so it's somewhat robust. On the other hand, all three were susceptible to Simpson's Paradox and demographic bias, so there is one possible source of correlated error (specifically, more at-risk populations have higher vaccination rates). However, even if we assume a best-case there, though, transmission is reduced by <90%.

mythrwy 5y ago

`The argument that vaccines don't prevent delta tranmission are based on headlines, not science.` That is not the case. https://www.nature.com/articles/d41586-021-02187-1 https://www.nature.com/articles/d41586-021-02187-1 "“The bottom line is, this can happen — it can be true that vaccinated people can spread the virus. But we do not yet know what their relative role in overall community spread is,” says co-author Thomas Friedrich, a virologist at the University of Wisconsin–Madison." Vaccinations may (or may not) reduce the propensity of vaccinated people to spread Delta but it's very clear at this point vaccinated people can spread Delta to some degree.

lamontcg 5y ago
I'll help you out, here's a documented case of transmission from one breakthrough infection to another breakthrough infection to two more: https://wwwnc.cdc.gov/eid/article/27/12/21-1792_article https://wwwnc.cdc.gov/eid/article/27/12/21-1792_article It is 100% certain that some breakthrough transmissions can transmit onwards. If I know that, it should be very apparent that wasn't what I meant. There are people claiming that vaccines do not prevent any forwards transmission and that vaccination is 100% worthless for ending pandemic spread. Arguing that is wrong does not imply arguing for the exact inverse and that vaccines are perfect. I'm pretty sure that hell is the world where everyone argues in absolutes all the time and that I'm unfortunately living in it.

blagie 5y ago

sigh All of this is irrelevant to the central point. The article fabricated facts. If you're a scientist, your conclusion can be 100% and you're still a fraud if you've baked data to get to that conclusion. As a footnote, we do have data. My best estimate was that the vaccine reduced the transmission of delta by about 50%. That's based on data in the community I live (and this is context-dependent -- for example, vaccines do a lot more for casual interactions than for close/long ones). I saw that same estimate replicated by two data scientists I trust, using different data from different places, and different methodologies, so it's somewhat robust. On the other hand, all three were susceptible to Simpson's Paradox and demographic bias, so there is one possible source of correlated error (specifically, more at-risk populations have higher vaccination rates). However, even if we assume a best-case there, though, transmission is reduced by <90%.