Abstract
Background: There is a lack of data regarding how the Delta variant of coronavirus disease 2019 (COVID-19) has impacted the effectiveness of the BNT162b2 (Pfizer-BioNTech), mRNA-1273 (Moderna), and Ad26.COV2.S (Johnson & Johnson-Janssen) vaccines at preventing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and COVID-19 hospitalization.
Methods: We compared the effectiveness of the three vaccines during the pre- and post-Delta variant period (before and after 1 July 2021) in a large cohort of vaccinated and unvaccinated patients in the Michigan Medicine healthcare system. We assessed vaccine effectiveness (VE) using 2 analyses: an inverse propensity weighted (IPW) Kaplan-Meier (KM) analysis based on time from vaccination, and a Cox model based on calendar time with vaccination as a time-varying covariate.
Results: Compared to Ad26.COV2.S recipients, the risk of hospitalization for COVID-19 in the post-Delta variant period was lower for BNT162b2 recipients (hazard ratio [HR] = 0.37; 95% confidence interval [CI]: [.14-.98]; P = .05) and mRNA-1273 recipients (HR = 0.21; 95% CI: [.07-.64]; P = .006). Recipients of the mRNA-1273 vaccine had a lower risk of SARS-CoV-2 infection than Ad26.COV2.S recipients (HR = 0.6; 95% CI: [.43-.83]; P = .003) and BNT162b2 recipients (HR = 0.64; 95% CI: [.54-.76]; P < .001). After 1 July, efficacy against SARS-CoV-2 infection declined for Ad26.COV2.S recipients (VE = 76% before; VE = 49% after; P = .02), BNT162b2 recipients (VE = 87% before; VE = 52% after; P < .001), and mRNA-1273 recipients (VE = 92% before; VE = 70% after; P < .001). Waning immunity and the Delta variant contributed independently and significantly to this decline.
Conclusions: Although there is a substantial decline in effectiveness, the approved COVID-19 vaccines remain effective against infection and hospitalization due to the Delta variant. The mRNA-based vaccines are more effective than the Ad26.COV2.S vaccine.
Keywords: COVID-19; COVID-19 vaccines; Delta variant; comparative effectiveness; waning immunity.
【저자키워드】 COVID-19, delta variant, COVID-19 vaccines, comparative effectiveness, waning immunity, 【초록키워드】 coronavirus disease, SARS-CoV-2, Coronavirus disease 2019, Efficacy, Vaccine, coronavirus, COVID-19 vaccine, vaccination, Immunity, Hospitalization, mRNA-1273, SARS-COV-2 infection, variant, Infection, Delta, risk, severe acute respiratory syndrome Coronavirus, delta variant, BNT162b2, Medicine, COVID-19 vaccines, Ad26.COV2.S, mRNA, Patient, Effectiveness, COVID-19 hospitalization, large cohort, Pfizer-BioNTech, Moderna, Analysis, waning immunity, Healthcare system, mRNA-1273 vaccine, acute respiratory syndrome, 95% CI, acute respiratory syndrome coronavirus, acute respiratory syndrome coronavirus 2, 95% confidence interval, recipients, hazard ratio, lower risk, covariate, Ad26, Ad26.COV2.S vaccine, mRNA-based vaccines, Kaplan-Meier, recipient, mRNA-based vaccine, effective, Cox model, lack, significantly, approved, contributed, impacted, declined, IPW, 【제목키워드】 Delta, Comparative, Against,