Saw this from the twitter feed of Shane Crotty at the LaJolla Institute. The Limeys just released a pretty thorough study regarding the effectiveness of vaccines and natural immunity against Delta.
Takeaways are partly what we have already heard . . .Delta reduces the efficacy of both vaccines and natural immunity. Breakthrough cases exhibit the same peak viral load between vaccinated and unvaccinated but the vaccinated tend to recovery very quickly after a 5 day or so period whereas the unvaxxed do not.
The different takeaway was that there was not difference between prior infection natural immunity and MRNA vaccine induced immunity. That contradicts the line out of Israel that has made headlines.
They also note the combo of prior natural immunity plus vaccine booster produces the best line of defense.
https://www.medrxiv.org/content/10.1101/2021.08.18.21262237v1
Takeaways are partly what we have already heard . . .Delta reduces the efficacy of both vaccines and natural immunity. Breakthrough cases exhibit the same peak viral load between vaccinated and unvaccinated but the vaccinated tend to recovery very quickly after a 5 day or so period whereas the unvaxxed do not.
The different takeaway was that there was not difference between prior infection natural immunity and MRNA vaccine induced immunity. That contradicts the line out of Israel that has made headlines.
They also note the combo of prior natural immunity plus vaccine booster produces the best line of defense.
https://www.medrxiv.org/content/10.1101/2021.08.18.21262237v1
Quote:
A single dose of the mRNA-1273 vaccine had similar or greater effectiveness compared to a single dose of BNT162b2 or ChAdOx1. Effectiveness of two doses remains at least as great as protection afforded by prior natural infection. The dynamics of immunity following second doses differed significantly between BNT162b2 and ChAdOx1, with greater initial effectiveness against new PCR-positives but faster declines in protection against high viral burden and symptomatic infection with BNT162b2. There was no evidence that effectiveness varied by dosing interval, but protection was higher among those vaccinated following a prior infection and younger adults.
With Delta, infections occurring following two vaccinations had similar peak viral burden to those in unvaccinated individuals. SARS-CoV-2 vaccination still reduces new infections, but effectiveness and attenuation of peak viral burden are reduced with Delta.