Effectiveness of Pfizer-BioNTech and Moderna Vaccines in Preventing SARS-CoV-2 Infection Among Nursing Home Residents Before and During Widespread Circulation of the SARS-CoV-2 B.1.617.2 (Delta) Variant — National Healthcare Safety Network, March 1–August 1, 2021

Nanduri, Srinivas; Pilishvili, Tamara; Derado, Gordana; Soe, Minn; Dollard, Philip; Wu, Hsiu; Li, Qunna; Bagchi, Suparna; Dubendris, Heather; Link‐Gelles, Ruth; Jernigan, John A.; Budnitz, Daniel S.; Bell, Jeneita M.; Benin, Andrea L.; Shang, Nong; Edwards, Jonathan R.; Verani, Jennifer R.; Schrag, Stephanie J.

doi:10.15585/mmwr.mm7034e3

Cited by 310 publications

(288 citation statements)

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“…These findings are consistent with preliminary reports from the Israel Ministry of Health and US Centers for Disease Control and Prevention showing reductions in effectiveness of BNT162b2 against infections 5 months or longer after being fully vaccinated, but consistently high estimates against COVID-19-related hospital admissions and severe disease up until July, 2021. 24 , 25 , 26 , 27 The most recent report from August, 2021, from Israel, however, suggests that some reduction in effectiveness against hospital admissions has been observed among older people ( ≥ 65 years) roughly 6 months after receiving the second dose of BNT162b2. 31 Thus, long-term effectiveness data against severe outcomes should be continuously monitored in our study population and globally.…”

Section: Discussionmentioning

confidence: 99%

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Effectiveness of mRNA BNT162b2 COVID-19 vaccine up to 6 months in a large integrated health system in the USA: a retrospective cohort study

et al. 2021

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Background Vaccine effectiveness studies have not differentiated the effect of the delta (B.1.617.2) variant and potential waning immunity in observed reductions in effectiveness against SARS-CoV-2 infections. We aimed to evaluate overall and variant-specific effectiveness of BNT162b2 (tozinameran, Pfizer–BioNTech) against SARS-CoV-2 infections and COVID-19-related hospital admissions by time since vaccination among members of a large US health-care system. Methods In this retrospective cohort study, we analysed electronic health records of individuals (≥12 years) who were members of the health-care organisation Kaiser Permanente Southern California (CA, USA), to assess BNT162b2 vaccine effectiveness against SARS-CoV-2 infections and COVID-19-related hospital admissions for up to 6 months. Participants were required to have 1 year or more previous membership of the organisation. Outcomes comprised SARS-CoV-2 PCR-positive tests and COVID-19-related hospital admissions. Effectiveness calculations were based on hazard ratios from adjusted Cox models. This study was registered with ClinicalTrials.gov , NCT04848584 . Findings Between Dec 14, 2020, and Aug 8, 2021, of 4 920 549 individuals assessed for eligibility, we included 3 436 957 (median age 45 years [IQR 29–61]; 1 799 395 [52·4%] female and 1 637 394 [47·6%] male). For fully vaccinated individuals, effectiveness against SARS-CoV-2 infections was 73% (95% CI 72–74) and against COVID-19-related hospital admissions was 90% (89–92). Effectiveness against infections declined from 88% (95% CI 86–89) during the first month after full vaccination to 47% (43–51) after 5 months. Among sequenced infections, vaccine effectiveness against infections of the delta variant was high during the first month after full vaccination (93% [95% CI 85–97]) but declined to 53% [39–65] after 4 months. Effectiveness against other (non-delta) variants the first month after full vaccination was also high at 97% (95% CI 95–99), but waned to 67% (45–80) at 4–5 months. Vaccine effectiveness against hospital admissions for infections with the delta variant for all ages was high overall (93% [95% CI 84–96]) up to 6 months. Interpretation Our results provide support for high effectiveness of BNT162b2 against hospital admissions up until around 6 months after being fully vaccinated, even in the face of widespread dissemination of the delta variant. Reduction in vaccine effectiveness against SARS-CoV-2 infections over time is probably primarily due to waning immunity with time rather than the delta variant escaping vaccine protection. Funding Pfizer.

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Section: Discussionmentioning

confidence: 99%

“…After global transmission of the delta variant in June and July, 2021, reports describing reduced effectiveness of BNT162b2 (and other COVID-19 vaccines) against SARS-CoV-2 infections caused by the delta variant began to surface from Israel, 25 Qatar, 23 and the USA. 26 , 27 …”

Section: Introductionmentioning

confidence: 99%

Effectiveness of mRNA BNT162b2 COVID-19 vaccine up to 6 months in a large integrated health system in the USA: a retrospective cohort study

et al. 2021

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“…Protection against COVID-19-associated hospitalization remained high despite the emergence of Delta as the predominant variant in the United States; protection was similar during periods before (February-June 2021; 84.1%) and during (July-August 2021; 89.3%) Delta variant predominance. Recent reports have shown that COVID-19 vaccine protection against SARS-CoV-2 infection is lower in areas with increasing Delta variant transmission (7,8); however, protection against severe disease outcomes, including hospitalization, remains high (7,9).…”

Section: Discussionmentioning

confidence: 99%

Effectiveness of COVID-19 mRNA Vaccines Against COVID-19–Associated Hospitalization — Five Veterans Affairs Medical Centers, United States, February 1–August 6, 2021

Bajema¹,

Dahl²,

Prill³

et al. 2021

MMWR Morb. Mortal. Wkly. Rep.

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106

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this report was posted as an MMWR Early Release on the MMWR website (https://www.cdc.gov/mmwr).COVID-19 mRNA vaccines (Pfizer-BioNTech and Moderna) have been shown to be highly protective against COVID-19associated hospitalizations (1-3). Data are limited on the level of protection against hospitalization among disproportionately affected populations in the United States, particularly during periods in which the B.1.617.2 (Delta) variant of SARS-CoV-2, the virus that causes COVID-19, predominates (2). U.S. veterans are older, more racially diverse, and have higher prevalences of underlying medical conditions than persons in the general U.S. population (2,4). CDC assessed the effectiveness of mRNA vaccines against COVID-19associated hospitalization among 1,175 U.S. veterans aged ≥18 years hospitalized at five Veterans Affairs Medical Centers (VAMCs) during February 1-August 6, 2021. Among these hospitalized persons, 1,093 (93.0%) were men, the median age was 68 years, 574 (48.9%) were non-Hispanic Black (Black), 475 were non-Hispanic White (White), and 522 (44.4%) had a Charlson comorbidity index score of ≥3 (5). Overall adjusted vaccine effectiveness against COVID-19-associated hospitalization was 86.8% (95% confidence interval [CI] = 80.4%-91.1%) and was similar before (February 1-June 30) and during (July 1-August 6) SARS-CoV-2 Delta variant predominance (84.1% versus 89.3%, respectively). Vaccine effectiveness was 79.8% (95% CI = 67.7%-87.4%) among adults aged ≥65 years and 95.1% (95% CI = 89.1%-97.8%) among those aged 18-64 years. COVID-19 mRNA vaccines are highly effective in preventing COVID-19-associated hospitalization in this older, racially diverse population of predominately male U.S. veterans. Additional evaluations of vaccine effectiveness among various age groups are warranted. To prevent COVID-19-related hospitalizations, all eligible persons should receive COVID-19 vaccination.

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“…While most studies reviewed here were conducted in a short time period after vaccination (< 6 months) and did not examine waning, this is currently a critical issue for COVID-19 vaccines, and new studies will help address this question over the next year. Several recent reports have suggested reductions in VE over time 16,41,117–120 , while the WHO regards current evidence as inconclusive and stresses prioritization of primary doses 121 . Despite this, several governments have already begun administering additional “booster” doses (e.g., France 122 , Israel 123 ), and others have announced tentative plans to do so in the future (e.g., US 124 ).…”

Section: Discussionmentioning

confidence: 99%

A systematic review of COVID-19 vaccine efficacy and effectiveness against SARS-CoV-2 infection and disease

Higdon

Wahl

Jones

et al. 2021

Preprint

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Billions of doses of COVID-19 vaccines have been administered around the world, dramatically reducing SARS-CoV-2 incidence in some settings. Many studies suggest vaccines provide a high degree of protection against infection and disease, but precise estimates vary and studies differ in design, outcomes measured, dosing regime, location, and circulating virus strains. Here we conduct a systematic review of COVID-19 vaccines as of August 2021. We included efficacy data from Phase 3 clinical trials for 13 vaccines within the WHO Emergency Use Listing evaluation process and real-world effectiveness for 5 vaccines with observational studies meeting inclusion criteria. Vaccine metrics collected include effects against asymptomatic infection, any infection, symptomatic COVID-19, and severe outcomes including hospitalization and death, for both partial and complete vaccination, and against SARS-CoV-2 variants of concern. In addition, we review the epidemiological principles behind the design and interpretation of vaccine effects, and explain important sources of heterogeneity between studies.

show abstract

Effectiveness of Pfizer-BioNTech and Moderna Vaccines in Preventing SARS-CoV-2 Infection Among Nursing Home Residents Before and During Widespread Circulation of the SARS-CoV-2 B.1.617.2 (Delta) Variant — National Healthcare Safety Network, March 1–August 1, 2021

Abstract: data-tracker/#variant-proportions Vaccine type/Period † Aggregate weekly count of residents No. of cases Vaccine effectiveness, % (95% CI) p-value** Unadjusted § Adjusted ¶ Any mRNA vaccine

Cited by 310 publications

References 6 publications

Effectiveness of mRNA BNT162b2 COVID-19 vaccine up to 6 months in a large integrated health system in the USA: a retrospective cohort study

Effectiveness of mRNA BNT162b2 COVID-19 vaccine up to 6 months in a large integrated health system in the USA: a retrospective cohort study

Effectiveness of COVID-19 mRNA Vaccines Against COVID-19–Associated Hospitalization — Five Veterans Affairs Medical Centers, United States, February 1–August 6, 2021

A systematic review of COVID-19 vaccine efficacy and effectiveness against SARS-CoV-2 infection and disease

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