Why haven't data been released from vaccine trials on viral loads to assess reduced infectiousness? Since trials include testing cases for SARS-CoV-2, wouldn't all have 1+ sample from each case? N=185(Vac),11(Plac) (Moderna);162(V),8(P) (Pfizer/BioNtech)?
@nataliexdean @mlipsitch
@nataliexdean @mlipsitch
These aren't huge sample sizes for the vaccinated group, but I'm betting there have been more cases in both groups since these results were reported & big effects could be detected even with smallish sample sizes. Given importance of reducing transmission this is big Q.
More explanation: we still have no data on whether Pfizer/Moderna vaccines reduce infection/infectiousness. All we know is it reduces chance of symptomatic infection. If they don't reduce infectiousness, then they don't protect pop around vaccinated person.
This makes a huge difference in vaccine allocation. If vaccines reduce infectiousness, then vaccinating nursing home workers would protect at-risk residents. If not, we'd need to vaccinate all residents to protect them. Same for other groups interacting with at risk individuals.
This even matters when vaccine is widely available. If it doesn't reduce transmission, those not protected (due to refusal to get vaccinated, poor immune response, etc.) would be at-risk. If so, masks, distancing still needed by many.
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