Thread by @NidaQadirMD

Very excited to share our most recent publication about #CovidVaccine effectiveness, just published today by the IVY network. Especially relevant in light of today’s news about #boosters (spoiler - I’m skeptical about the need for boosters for all). 🧵

cdc.gov/mmwr/volumes/7…

➡️We looked specifically at vaccine effectiveness for preventing #COVID19 hospitalizations.

➡️We did NOT look at asymptomatic infections, or infections that did not result in hospitalization.

➡️Fully vaccinated = received 2nd dose of vaccine > 14 days prior to hospitalization

What we found:

➡️Vaccine effectiveness (VE) for preventing #COVID19 hospitalizations was 86% overall.

➡️Vaccine effectiveness was sustained for 6 months after full immunization - strikingly illustrated in this figure:

➡️VE was overall lower for immunocompromised patients - 63% vs 90% in non-immunocompromised

➡️VE for high-risk patients (age > 65, immunocompromised, or w/ multiple comorbidities) also seemed to be sustained over time, but the immunocompromised group needs to be studied further

Limitations:

➡️Time period = up to 6 months post-vax, so we still don’t know if VE wanes after that (we’re continuing the study to find out)

➡️The #DeltaVariant was not the dominant variant until mid-June. While VE was similar in June & July, further surveillance is needed

This leaves me a bit skeptical about boosters because so far, it seems that although protection against mild illness wanes, vaccines remain highly effective at preventing hospitalization.

We would prevent many more cases of severe illness if we focused on vaccinating the unvaccinated instead of boosters. Great thread on this from @EpiEllie here:

https://twitter.com/NidaQadirMD/status/1423758727363002374

That being said, VE is lower among specific populations, leaving them more vulnerable. We need to examine how to better protect our immunocompromised patients in particular, whether it’s by using boosters or otherwise.

The study continues and there’s more to come, including evaluating VE over a longer period of time, and a closer look at immunocompromised patients. It’s been such a privilege to work with such an awesome group of investigators & contribute to this work.