Thread by @AbraarKaran

Excellent news from @CDCMMWR today!

Under real-world conditions, vaccine effectiveness of mRNA (Moderna, Pfizer) vaccines:
-90% after 2 doses
-80% after one dose (both measured 14 days after dose) #covid19

cdc.gov/mmwr/volumes/7…

2/ "Prospective cohorts of 3,950 health care personnel, first responders, and other essential and frontline workers completed weekly SARS-CoV-2 testing for 13 consecutive weeks."

Data collected from eight U.S. locations during December 14, 2020–March 13, 2021 #covid19

3/ "CDC routinely tested for SARS-CoV-2 infections every week regardless of symptom status and at the onset of symptoms consistent with COVID-19–associated illness."

Gets at one of the biggest questions since the vaccines came out: extent of reduction in asymptomatic cases

4/
"3 PCR-confirmed infections occurred during 78,902 person-days with full immunization (≥14 days after 2nd dose; incidence rate= 0.04/1,000 person-days)"

8 PCR-confirmed infections/ 41,856 person-days w/ partial immunization (≥14 days after 1st/before 2nd);0.19/1,000 PDs

4.5/
also worth noting limitation: "vaccine effectiveness point estimates should be interpreted w/ caution given the moderately wide CIs attributable in part to the limited number of postimmunization PCR-confirmed infections observed"

#covid19

5/ "Reducing the risk for transmissible infection, which can occur among persons with asymptomatic infection or among persons several days before symptoms onset (6), is especially important among health care personnel, first responders, and other essential and frontline workers"