> Two doses of BNT162b2 or ChAdOx1 vaccines in Alpha variant index cases independently reduced PCR-positivity in contacts (aOR, adjusted odds ratio vs. unvaccin

> Two doses of BNT162b2 or ChAdOx1 vaccines in Alpha variant index cases independently reduced PCR-positivity in contacts (aOR, adjusted odds ratio vs. unvaccinated=0.18[95%CI 0.12-0.29] and 0.37[0.22-0.63] respectively). > The Delta variant attenuated vaccine-associated reductions in transmission: two BNT162b2 doses reduced Delta transmission (aOR=0.35[0.26-0.48]), more than ChAdOx1 (aOR=0.64[0.57-0.72]; heterogeneity p<0.001). > Variation in viral load (Ct values) explained only a modest proportion of vaccine-associated transmission reductions. > Transmission reductions declined over time since second vaccination, for Delta reaching similar levels to unvaccinated individuals by 12 weeks for ChAdOx1 and attenuating substantially for BNT162b2. Legend: aOR: adjusted odds ratio. 1 => no effect, < 1 => positive effect, > 1 => negative effect. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2938757 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2938757 BNT162b2: Pfizer mRNA covid vaccine. ChAdOx1: J&J adenovirus covid vaccine. If I interpret the results correctly, as antibody concentrations decrease with time, virus transmission increases, to the point that J&J has no virus transmission protection after only 3 months and Pfizer being "attenuated substantially". This explains the boost push, as boosters re-increase the antibody concentrations, at least for a few iterations. Boost baby, boost!