the staff of the Ridgewood blog
Ridgewood NJ, on April 2, a team of researchers led by the US CDC COVID-19 Response Team published interim estimates of a prospective cohort study describing the effectiveness of the two-dose Pfizer-BioNTech and Moderna SARS-CoV-2 mRNA vaccines among healthcare and other frontline workers. The report, published in the CDC’s Morbidity and Mortality Weekly Report (MMWR), describes data collected from December 14, 2020 to March 13, 2021, through the HEROES-RECOVER network of 8 US sites. Overall, 3,950 frontline workers (i.e., those who routinely are within 3 feet of other individuals as part of their occupation) with no prior laboratory documentation of SARS-CoV-2 infection were included in the analysis. Participants were actively monitored for COVID-19 symptoms and self-collected weekly nasal swabs which were tested for SARS-CoV-2 infection.
Among the 3,950 participants, 2,479 (62.8%) received both recommended vaccine doses and 477 (12.1%) received only one dose of vaccine during the 13-week study period. For the duration of observation, there were 78,902 person-days followed for fully vaccinated individuals (two weeks or more post-second dose), 41,856 person-days of observation for partially vaccinated individuals (two weeks or more after first dose through receipt of second dose) and 116,657 person-days of observation for unvaccinated individuals (no doses received). 161 infections were identified among the unvaccinated group (1.38 infections per 1,000 person-days), 8 infections were identified among the partially vaccinated group (≥14 days after first dose and before second dose; 0.19 infections per 1,000 person-days), and 3 infections were identified among the fully vaccinated group (≥14 days after second dose; 0.04 infections per 1,000 person-days). The researchers note that the 13 days following participants’ first or second dose when immune status was indeterminate (67,483 person-days) were not included in analysis, but 33 infections were identified during that period of observation.
The unadjusted vaccine effectiveness for the partially immunized group was 82% (95% CI: 62-91) and 91% for the fully immunized group (95% CI: 73-97). The adjusted vaccine effectiveness for the partially immunized group was 80% (95% CI: 59-90) and 90% for the fully immunized group (95% CI: 68-97). Notably, a majority of infections were symptomatic with common COVID-19-associated symptoms (87.3%), but only two hospitalizations occurred and no deaths occurred. In light of these findings, the CDC encourages vaccinated individuals to continue taking public health precautions to prevent infection and transmission.
Its the daily rotating CDC recommendation.