Effectiveness of SARS-CoV-2 mRNA Vaccines for Preventing Covid-19 Hospitalizations in the United States

Abstract

BackgroundAs SARS-CoV-2 vaccination coverage increases in the United States (US), there is a need to understand the real-world effectiveness against severe Covid-19 and among people at increased risk for poor outcomes.MethodsIn a multicenter case-control analysis of US adults hospitalized March 11 - May 5, 2021, we evaluated vaccine effectiveness to prevent Covid-19 hospitalizations by comparing odds of prior vaccination with an mRNA vaccine (Pfizer-BioNTech or Moderna) between cases hospitalized with Covid-19 and hospital-based controls who tested negative for SARS-CoV-2.ResultsAmong 1210 participants, median age was 58 years, 22.8% were Black, 13.8% were Hispanic, and 20.6% had immunosuppression. SARS-CoV-2 lineage B.1.1.7 was most common variant (59.7% of sequenced viruses). Full vaccination (receipt of two vaccine doses ≥14 days before illness onset) had been received by 45/590 (7.6%) cases and 215/620 (34.7%) controls. Overall vaccine effectiveness was 86.9% (95% CI: 80.4 to 91.2%). Vaccine effectiveness was similar for Pfizer-BioNTech and Moderna vaccines, and highest in adults aged 18-49 years (97.3%; 95% CI: 78.9 to 99.7%). Among 45 patients with vaccine-breakthrough Covid hospitalizations, 44 (97.8%) were ≥50 years old and 20 (44.4%) had immunosuppression. Vaccine effectiveness was lower among patients with immunosuppression (59.2%; 95% CI: 11.9 to 81.1%) than without immunosuppression (91.3%; 95% CI: 85.5 to 94.7%).ConclusionDuring March–May 2021, SARS-CoV-2 mRNA vaccines were highly effective for preventing Covid-19 hospitalizations among US adults. SARS-CoV-2 vaccination was beneficial for patients with immunosuppression, but effectiveness was lower in the immunosuppressed population.

Evaluation of COVID-19 vaccine breakthrough infections among immunocompromised patients fully vaccinated with BNT162b2

“…The findings of this study complement and expand on those of other recent real-world studies that have indicated reduced COVID-19 vaccine protection for some IC patient groups [13][14][15][16][17][18][19][20][21]. In a US study of hospitalized patients, Tenforde et al found that of the 45 hospitalized COVID-19 cases, 44% were IC; mRNA VE against COVID-19 hospitalization was estimated at 63% for those who were IC and 91% among those who were not [13].…”

“…Currently, there is limited information in the published literature on whether a suboptimal immune response to the COVID-19 mRNA vaccines among those with IC conditions [8][9][10][11][12] leads to reduced vaccine effectiveness (VE). Some recently conducted real-world studies that included subpopulations with IC conditions have found that while the COVID-19 vaccines were effective in this patient group, VE against SARS-CoV-2 infection, symptomatic illness, and COVID-19-related hospitalization was lower than observed in the general population, with VE ranging from 63% to 90% [13][14][15][16][17][18][19][20][21].…”

Shoring Up Vaccine Efficacy

“…Immune response is also affected by malignancies, organ and stem cell transplants, immunosuppressive medications, human immunodeficiency virus infection, and primary immunodeficiencies. 1 However, there is a much larger group of individuals who fail to respond adequately to vaccination and to whom none of these classic immunosuppression conditions apply. Recent research has provided important new clues about how to help them.…”

Seroresponse to SARS-CoV-2 vaccines among maintenance dialysis patients over six months

“…Concerns about the robustness of the vaccine-induced immune response in vulnerable populations 5–7 have prompted the Centers for Disease Control and Prevention (CDC) to recommend an additional dose for immunocompromised patients, 8 while concerns about the durability of response have prompted discussion of booster doses of vaccine. 9 The implications for patients receiving maintenance dialysis remain unclear at this time.…”

“…1 The three vaccines currently authorized for use by the Food and Drug Administration, either with approval or emergency use authorization, are all highly effective at preventing death and serious illness in the general population. [2][3][4] Concerns about the robustness of the vaccine-induced immune response in vulnerable populations [5][6][7] have prompted the Centers for Disease Control and Prevention (CDC) to recommend an additional dose for immunocompromised patients, 8 while concerns about the durability of response have prompted discussion of booster doses of vaccine. 9 The implications for patients receiving maintenance dialysis remain unclear at this time.…”