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.
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.
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.
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.
Pfizer.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Globally, recommendations are expanding for third (booster) doses of BNT162b2 (Pfizer–BioNTech). In the United States, as of November 19, 2021, boosters were recommended for all adults aged 18 years ...and older. We evaluated the effectiveness of a third dose of BNT162b2 among adults in a large US integrated health system.
In this retrospective cohort study, we analyzed electronic health records from Kaiser Permanente Southern California between Dec 14, 2020 and Dec 5, 2021 to assess vaccine effectiveness (VE) of two and three doses of BNT162b2 against SARS-CoV-2 infections (without hospital admission) andCOVID-19-related hospital admission. VE was calculated using hazards ratios from adjusted Cox models.
After only two doses, VE against infection declined from 85% (95% CI 83–86) during the first month to 49% (46–51) ≥ 7 months following vaccination. Overall VE against hospitalization was 90% (95% CI 86–92) within one month and did not wane, however, effectiveness against hospitalization appeared to wane among immunocompromised individuals but was not statistically significant (93% 72–98 at 1 month to 74% 45–88 after ≥ 7 months; p=0·490). Three-dose VE (median follow-up 1·3 months SD 0·6) was 88% (95% CI 86–89) against infection and 97% (95–98) against hospitalization. Effectiveness after three doses was higher than that seen one month after receiving only two doses for both outcomes. Relative VE of three doses compared to two (with at least six months after the second dose) was 75% (95% CI 71−78) against infections and 70% (48−83) against hospital admissions.
These data support the benefit of broad BNT162b2 booster recommendations, as three doses confers comparable, if not better, protection against SARS-CoV-2 infections and hospital admission as was seen soon after receiving two doses.
Pfizer Inc.
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It is imperative to evaluate health related quality of life (HRQoL) pre-COVID-19, but there is currently no evidence of the retrospective application of the EuroQol 5-Dimension, 5 level version ...(EQ-5D-5L) for COVID-19 studies. Symptomatic patients with SARS-CoV-2 at CVS Health US test sites were recruited between 01/31/2022-04/30/2022. Consented participants completed the EQ-5D-5L questionnaire twice: a modified version where all the questions were past tense to retrospectively assess pre-COVID-19 baseline QoL, and the standard version in present tense to assess current HRQoL. Duncan's new multiple range test was adopted for post analysis of variance pairwise comparisons of EQ visual analog scale (EQ VAS) means between problem levels for each of 5 domains. A linear mixed model was applied to check whether the relationship between EQ VAS and utility index (UI) was consistent pre-COVID-19 and during COVID-19. Matching-adjusted indirect comparison was used to compare pre-COVID-19 UI and EQ VAS scores with those of the US population. Lastly, Cohen's d was used to quantify the magnitude of difference in means between two groups. Of 676 participants, 10.2% were age 65 or more years old, 73.2% female and 71.9% white. Diabetes was reported by 4.7% participants and hypertension by 11.2%. The estimated coefficient for the interaction of UI-by-retrospective collection indicator (0 = standard prospective collection, 1 = retrospective for pre-COVID-19), -4.2 (SE: 3.2), P = 0.197, indicates that retrospective collection does not significantly alter the relationship between EQ VAS and UI. After adjusting for age, gender, diabetes, hypertension, and percent of mobility problems, the predicted means of pre-COVID-19 baseline EQ VAS and UI were 84.6 and 0.866, respectively. Both means were close to published US population norms (80.4 and 0.851) compared to those observed (87.4 and 0.924). After adjusting for age, gender, diabetes, and hypertension, the calculated ES between pre-COVID-19 and COVID-19 for UI and EQ VAS were 0.15 and 0.39, respectively. Without retrospectively collected EQ-5D-5L, using US population norms tended to underestimate the impact of COVID-19 on HRQoL. At a group level the retrospectively collected pre-COVID-19 EQ-5D-5L is adequate and makes it possible to directly evaluate the impact of COVID-19 on HRQoL. (ClinicalTrials.gov NCT05160636)
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Although Clostridioides difficile infection (CDI) incidence is high in the United States, standard-of-care (SOC) stool collection and testing practices might result in incidence overestimation or ...underestimation. We conducted diarrhea surveillance among inpatients >50 years of age in Louisville, Kentucky, USA, during October 14, 2019–October 13, 2020; concurrent SOC stool collection and CDI testing occurred independently. A study CDI case was nucleic acid amplification test‒/cytotoxicity neutralization assay‒positive or nucleic acid amplification test‒positive stool in a patient with pseudomembranous colitis. Study incidence was adjusted for hospitalization share and specimen collection rate and, in a sensitivity analysis, for diarrhea cases without study testing. SOC hospitalized CDI incidence was 121/100,000 population/year; study incidence was 154/100,000 population/year and, in sensitivity analysis, 202/100,000 population/year. Of 75 SOC CDI cases, 12 (16.0%) were not study diagnosed; of 109 study CDI cases, 44 (40.4%) were not SOC diagnosed. CDI incidence estimates based on SOC CDI testing are probably underestimated.
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XBB-related omicron sublineages have recently replaced BA.4/5 as the predominant omicron sublineages in the USA and other regions globally. Despite preliminary signs of immune evasion of XBB ...sublineages, few data exist describing the real-world effectiveness of bivalent COVID-19 vaccines, especially against XBB-related illness. We aimed to investigate the effectiveness of the Pfizer--BioNTech BNT162b2 BA.4/5 bivalent vaccine against both BA.4/5-related and XBB-related disease in adults aged 18 years or older.
In this test-negative case-control study, we estimated the effectiveness of the BNT162b2 BA.4/5 bivalent vaccine using data from electronic health records of Kaiser Permanente Southern California health system members aged 18 years or older who received at least two doses of the wild-type COVID-19 mRNA vaccines. Participants sought care for acute respiratory infection between Aug 31, 2022, and April 15, 2023, and were tested for SARS-CoV-2 via PCR tests. Relative vaccine effectiveness (≥2 doses of wild-type mRNA vaccine plus a BNT162b2 BA.4/5 bivalent booster vs ≥2 doses of a wild-type mRNA vaccine alone) and absolute vaccine effectiveness (vs unvaccinated individuals) was estimated against critical illness related to acute respiratory infection (intensive care unit ICU admission, mechanical ventilation, or inpatient death), hospital admission, emergency department or urgent care visits, and in-person outpatient encounters with odds ratios from logistic regression models adjusted for demographic and clinical factors. We stratified vaccine effectiveness estimates for hospital admission, emergency department or urgent care visits, and outpatient encounters by omicron sublineage (ie, likely BA.4/5-related vs likely XBB-related), time since bivalent booster receipt, age group, number of wild-type doses received, and immunocompromised status. This study is registered with ClinicalTrials.gov (NCT04848584).
Analyses were conducted for 123 419 encounters (24 246 COVID-19 cases and 99 173 test-negative controls), including 4131 episode of critical illness (a subset of hospital admissions), 14 529 hospital admissions, 63 566 emergency department or urgent care visits, and 45 324 outpatient visits. 20 555 infections were BA.4/5 related and 3691 were XBB related. In adjusted analyses, relative vaccine effectiveness for those who received the BNT162b2 BA.4/5 bivalent booster compared with those who received at least two doses of a wild-type mRNA vaccine alone was an additional 50% (95% CI 23-68) against critical illness, an additional 39% (28-49) against hospital admission, an additional 35% (30-40) against emergency department or urgent care visits, and an additional 28% (22-33) against outpatient encounters. Waning of the bivalent booster from 0-3 months to 4-7 months after vaccination was evident for outpatient outcomes but was not detected for critical illness, hospital admission, and emergency department or urgent care outcomes. The relative effectiveness of the BNT162b2 BA.4/5 bivalent booster for XBB-related infections compared with BA.4/5-related infections was 56% (95% CI 12-78) versus 40% (27-50) for hospital admission; 34% (21-45) versus 36% (30-41) against emergency department or urgent care visits; and 29% (19-38) versus 27% (20-33) for outpatient encounters.
By mid-April, 2023, individuals previously vaccinated only with wild-type vaccines had little protection against COVID-19-including hospital admission. A BNT162b2 BA.4/5 bivalent booster restored protection against a range of COVID-19 outcomes, including against XBB-related sublineages, with the most substantial protection observed against hospital admission and critical illness.
Pfizer.
Although
Clostridioides difficile
infection (CDI) incidence is high in the United States, standard-of-care (SOC) stool collection and testing practices might result in incidence overestimation or ...underestimation. We conducted diarrhea surveillance among inpatients
>
50 years of age in Louisville, Kentucky, USA, during October 14, 2019–October 13, 2020; concurrent SOC stool collection and CDI testing occurred independently. A study CDI case was nucleic acid amplification test‒/cytotoxicity neutralization assay‒positive or nucleic acid amplification test‒positive stool in a patient with pseudomembranous colitis. Study incidence was adjusted for hospitalization share and specimen collection rate and, in a sensitivity analysis, for diarrhea cases without study testing. SOC hospitalized CDI incidence was 121/100,000 population/year; study incidence was 154/100,000 population/year and, in sensitivity analysis, 202/100,000 population/year. Of 75 SOC CDI cases, 12 (16.0%) were not study diagnosed; of 109 study CDI cases, 44 (40.4%) were not SOC diagnosed. CDI incidence estimates based on SOC CDI testing are probably underestimated.
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