Interim Estimates of Vaccine Effectiveness of Pfizer-BioNTech and Moderna COVID-19 Vaccines Among Health Care Personnel — 33 U.S. Sites, January–March 2021

Abstract

On May 14, 2021, this report was posted as an MMWR Early Release on the MMWR website (https://www.cdc.gov/mmwr).Throughout the COVID-19 pandemic, health care personnel (HCP) have been at high risk for exposure to SARS-CoV-2, the virus that causes COVID-19, through patient interactions and community exposure (1). The Advisory Committee on Immunization Practices recommended prioritization of HCP for COVID-19 vaccination to maintain provision of critical services and reduce spread of infection in health care settings (2). Early distribution of two mRNA COVID-19 vaccines (Pfizer-BioNTech and Moderna) to HCP allowed assessment of the effectiveness of these vaccines in a real-world setting. A test-negative case-control study is underway to evaluate mRNA COVID-19 vaccine effectiveness (VE) against symptomatic illness among HCP at 33 U.S. sites across 25 U.S. states. Interim analyses indicated that the VE of a single dose (measured 14 days after the first dose through 6 days after the second dose) was 82% (95% confidence interval [CI] = 74%-87%), adjusted for age, race/ethnicity, and underlying medical conditions. The adjusted VE of 2 doses (measured ≥7 days after the second dose) was 94% (95% CI = 87%-97%). VE of partial (1-dose) and complete (2-dose) vaccination in this population is comparable to that reported from clinical trials and recent observational studies, supporting the effectiveness of mRNA COVID-19 vaccines against symptomatic disease in adults, with strong 2-dose protection.A test-negative design case-control study of mRNA COVID-19 VE is underway, with HCP being enrolled at 33 sites across 25 U.S. states; the planned interim analysis presented in this report includes data collected during January-March 2021.* A majority (75%) of enrolled HCP worked at acute care hospitals (including emergency departments), 25% worked in outpatient or specialty clinics, and <1% worked in long-term care facilities and urgent care * https://www.cdc.gov/vaccines/covid-19/downloads/hcp-early-phaseprotocol-508.pdf

SARS-CoV-2 Portrayed against HIV: Contrary Viral Strategies in Similar Disguise

“…Prolonged viral replication in immunocompromised hosts may favor the generation and selection of nAb escape mutants, which in turn drives Ab affinity maturation and eventually enhanced neutralization breadth and potency [ 223 ]. In humans, previous SARS-CoV-2 infection and anti-spike Ab seropositivity significantly reduce the risk of SARS-CoV-2 reinfection [ 215 , 224 , 225 , 226 , 227 , 228 , 229 ], which is in line with vaccination outcome analyses [ 230 , 231 , 232 , 233 , 234 , 235 , 236 ] altogether implying that SARS-CoV-2 binding and/or nAbs exert protective effects. Consequently, neutralization levels have been found highly predictive of immune protection with seven current vaccines and in convalescent cohorts, and provide an evidence-based model of SARS-CoV-2 immune protection [ 237 ].…”

SARS-CoV-2 Portrayed Against HIV: Contrary Viral Strategies in Similar Disguise

“…Prolonged viral replication in immunocompromised hosts may favor the generation and selection of nAb escape mutants, which in turn drives Ab affinity maturation and eventually enhanced neutralization breadth and potency [223]. In humans, previous SARS-CoV-2 infection and anti-spike Ab seropositivity significantly reduce the risk of SARS-CoV-2 reinfection [215,[224][225][226][227][228][229], which is in line with vaccination outcome analyses [230][231][232][233][234][235][236] altogether implying that SARS-CoV-2 binding and/or nAbs exert protective effects. Consequently, neutralization levels have been found highly predictive of immune protection with seven current vaccines and in convalescent cohorts, and provide an evidence-based model of SARS-CoV-2 immune protection [237].…”

Accelerated COVID-19 vaccine development: milestones, lessons, and prospects

“… Real-world vaccine effectiveness (RWE) as assessed by case-control and observational studies of authorized two-dose regimens for Pfizer/BioNTech, Moderna, and AstraZeneca products ( Abu-Raddad et al., 2021 ; Andrejko et al., 2021 ; Angel et al., 2021 ; Aran, 2021 ; Bahl et al., 2021 ; Bernal et al., 2021 ; Björk et al., 2021 ; Butt et al., 2021 ; Cavanaugh et al., 2021 ; CDC, 2021b ; Chemaitelly et al., 2021 ; Chodick et al., 2021 ; Chung et al., 2021 ; Corchado-Garcia et al., 2021 ; Dagan et al., 2021 ; Fabiani et al., 2021 ; Goldberg et al., 2021 ; Haas et al., 2021 ; Hall et al., 2021 ; Lopez Bernal et al., 2021 ; Lumley et al., 2021 ; Martínez-Baz et al., 2021 ; Menni et al., 2021 ; Moustsen-Helms et al., 2021 ; Nasreen et al., 2021 ; Pawlowski et al., 2021 ; PHE, 2021 ; Pilishvili et al., 2021 ; Pritchard et al., 2021 ; Regev-Yochay et al., 2021 ; Sheikh et al, 2021 ; Stowe et al., 2021 ; Swift et al., 2021 ; Tande et al., 2021 ; Tang et al., 2021 ; Tenforde et al., 2021a , 2021b ; Thompson et al., 2021a , 2021b ; Vahidy et al., 2021 ; Vasileiou et al., 2021 ; Yassi et al., 2021 ; Young-Xu et al., 2021 ; Zacay et al., 2021 ) and 1-dose for Janssen ( Corchado-Garcia et al., 2021 ). Value ranges for SARS-CoV-2 variants include vaccine effectiveness ag...…”