A new study out on the transmissibility of breakthrough infections. As usual with COVID, a little for everyone to hate and won't swing the debate fully between mandates or not (sigh)
Some talking points:
-The vaccines are less effective at stopping the transmissibility of the Delta than previous variants (but we pretty much knew that already)
-The drop off effects are more severe in the elderly (which is why they are talking boosters)
-The vaccinated transmit the virus on less than the unvaccinated with naive (i.e. no prior infection) infections. This is due to: a) they are just simply less likely to catch it, b) they are sick for shorter periods, and c) they have smaller viral loads on average.
-But against the Delta the vaccinated can still transmit it on (and they leave open the question over whether the reduction is enough, as dad4 would put it, to make it all bloody over).
-Children are less likely to catch/transmit (in which case what are we, the US, doing in schools right now???)
The long and short of it is that this gives fuel for both sides of the vaccine mandate debate, without resolving it definitely one way or the other. On the one hand, there is substantial evidence that there is a public health benefit to vaccination even if they don't stop transmissions, because there is a substantial reduction in transmissions. On the other hand, even with vaccination you can still transmit on the virus and it is insufficiently clear if vaccination (given the waning immunity they also confirmed) is enough to end the pandemic. The matter is even more complicated for children, which we've seen from elsewhere have little risk and now seem to already transmit at a lower rate.
Background Pre-Delta, vaccination reduced transmission of SARS-CoV-2 from individuals infected despite vaccination, potentially via reducing viral loads. While vaccination still lowers the risk of infection, similar viral loads in vaccinated and unvaccinated individuals infected with Delta...
www.medrxiv.org