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1.
Ann Intern Med ; 175(3): 352-361, 2022 03.
Article in English | MEDLINE | ID: covidwho-1742919

ABSTRACT

BACKGROUND: Little is known about real-world COVID-19 vaccine effectiveness (VE) in racially and ethnically diverse, elderly populations with high comorbidity burden. OBJECTIVE: To determine the effectiveness of messenger RNA COVID-19 vaccines. DESIGN: Target trial emulation study comparing newly vaccinated persons with matched unvaccinated controls. SETTING: U.S. Department of Veterans Affairs health care system. PARTICIPANTS: Among persons receiving care in the Veterans Affairs health care system (n = 5 766 638), those who received at least 1 dose of the Moderna or Pfizer-BioNTech COVID-19 vaccine from 11 December 2020 to 25 March 2021 (n = 2 099 871) were matched to unvaccinated controls in a 1:1 ratio according to demographic, clinical, and geographic characteristics. INTERVENTION: Follow-up for SARS-CoV-2 infection or SARS-CoV-2-related death, defined as death within 30 days of infection, began after the vaccination date or an identical index date for the matched unvaccinated controls and continued until up to 30 June 2021. MEASUREMENTS: Vaccine effectiveness against SARS-CoV-2 infection or SARS-CoV-2-related death. RESULTS: Vaccinated and unvaccinated groups were well matched; both were predominantly male (92.9% vs. 93.4%), had advanced age (mean, 68.7 years in both groups), had diverse racial and ethnic distribution (for example, Black: 17.3% vs. 17.0%, Hispanic: 6.5% vs. 6.1%), and had substantial comorbidity burden. Vaccine effectiveness 7 or more days after the second vaccine dose was 69% (95% CI, 67% to 70%) against SARS-CoV-2 infection and 86% (CI, 82% to 89%) against SARS-CoV-2-related death and was similar when follow-up was extended to 31 March versus 30 June. Vaccine effectiveness against infection decreased with increasing age and comorbidity burden. LIMITATION: Predominantly male population and lack of data on SARS-CoV-2 variants. CONCLUSION: In an elderly, diverse, high-comorbidity population, COVID-19 VE against infection was substantially lower than previously reported, but VE against death was high. Complementary infection mitigation efforts remain important for pandemic control, even with vaccination. PRIMARY FUNDING SOURCE: U.S. Department of Veterans Affairs.


Subject(s)
COVID-19 , SARS-CoV-2 , Aged , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19 Vaccines , Delivery of Health Care , Female , Humans , Male , Vaccination
2.
EClinicalMedicine ; 45:101326-101326, 2022.
Article in English | EuropePMC | ID: covidwho-1728236

ABSTRACT

Background mRNA COVID-19 vaccines manufactured by Pfizer-BioNTech (BNT162b2) and Moderna (mRNA-1273) have been shown to be efficacious but have not been compared in head-to-head clinical trials. Methods We designed this observational study to emulate a target trial of COVID-19 vaccination by BNT162b2 versus mRNA-1273 among persons who underwent vaccination in the national U.S. Veterans Affairs (VA) healthcare system from 11/12/2020 to 25/03/2021 using combined VA and Medicare electronic health records. We identified the best matching mRNA-1273 recipient(s) for each BNT162b2 recipient, using exact/coarsened-exact matching (calendar week, VA integrated service network, age buckets and Charlson comorbidity index buckets) followed by propensity score matching. Vaccine recipients were followed from the date of first vaccine dose until 25/08/2021 for the development of SARS-CoV-2 infection, SARS-CoV-2-related hospitalization or SARS-CoV-2-related death. Findings Each group included 902,235 well-matched vaccine recipients, followed for a mean of 192 days, during which 16,890 SARS-CoV-2 infections, 3591 SARS-CoV-2-related hospitalizations and 381 SARS-CoV-2-related deaths were documented. Compared to BNT162b2, mRNA-1273 recipients had significantly lower risk of SARS-CoV-2 infection (adjusted hazard ratio [aHR] 0.736, 95% CI 0.696–0.779) and SARS-CoV-2-related hospitalization (aHR 0.633, 95% CI 0.562–0.713), which persisted across all age groups, comorbidity burden categories and black/white race. The differences between mRNA-1273 and BNT162b2 in risk of infection or hospitalization were progressively greater when the follow-up period was longer, i.e. extending to March 31, June 30 or August 25, 2021. These differences were more pronounced when we analyzed separately the outcomes that occurred during the follow-up period from July 1 to August 25, 2021 when the Delta variant became predominant in the U.S. (aHR for infection 0.584, 95% CI 0.533–0.639 and aHR for hospitalization 0.387, 95% 0.311–0.482). SARS-CoV-2-related deaths were less common in mRNA-1273 versus BNT162b2 recipients (168 versus 213) but this difference was not statistically significant (aHR 0.808, 95% CI 0.592–1.103). Interpretation In conclusion, although absolute rates of infection, hospitalization and death in both vaccine groups were low regardless of the vaccine received, our data suggests that compared to BNT162b2, vaccination with mRNA-1273 resulted in significantly lower rates of SARS-CoV-2-infection and SARS-CoV-2-related hospitalization. These differences were greater with longer follow-up time since vaccination and even more pronounced in the Delta variant era. Funding U.S. Department of Veterans Affairs, grant numbers COVID19–8900–11 and C19 21–278.

3.
PLoS One ; 16(12): e0259696, 2021.
Article in English | MEDLINE | ID: covidwho-1546942

ABSTRACT

BACKGROUND: We aimed to determine factors independently associated with early COVID-19 vaccination and adherence to two-dose regimens. METHODS: Among persons receiving care in the Veterans Affairs (VA) healthcare system (n = 5,766,638), we identified those who received at least one dose of COVID-19 vaccination through the VA, during the first ~3months following emergency use authorization, from December 11, 2020 to March 9, 2021 (n = 1,569,099, or 27.2%, including 880,200 (56.1%) Moderna, 676,279 (43.1%) Pfizer-BioNTech and 12,620 (0.8%) Janssen vaccines). RESULTS: Follow-up for receipt of vaccination began on December 11, 2020. After adjustment for baseline characteristics ascertained as of December 11, 2020, factors significantly associated with vaccination included older age, higher comorbidity burden, higher body mass index category, Black (vs. White) race (adjusted hazard ratio [AHR] 1.19, 95% CI 1.19-1.20), Hispanic (vs. non-Hispanic) ethnicity (AHR 1.12, 95% CI 1.11-1.13), urban (vs. rural) residence (AHR 1.31, 95% CI 1.31-1.31), and geographical region, while AI/AN race (vs. White), was associated with lower vaccination rate (AHR 0.85, 95% CI 0.84-0.87). Among persons who received both doses of Moderna or Pfizer-BioNTech vaccines, 95.3% received the second dose within ±4 days of the recommended date. Among persons who received the first vaccine dose, only 3.2% did not receive the second dose within 42 days for Pfizer versus 4.0% for Moderna (p<0.001). Factors independently associated with higher likelihood of missing the second dose included younger age (10.83% in 18-50 yo vs. 2.72% in 70-75 yo), AI/AN race, female sex, rural location, geographical region and prior positive test for SARS-CoV-2. CONCLUSIONS: We identified sociodemographic and clinical factors that may be used to target vaccination efforts and to further improve adherence to second vaccine dosing.


Subject(s)
COVID-19 Vaccines/administration & dosage , COVID-19/prevention & control , Medication Adherence/statistics & numerical data , Vaccination/statistics & numerical data , Adolescent , Adult , Age Factors , Aged , Aged, 80 and over , COVID-19/diagnosis , COVID-19/virology , Comorbidity , Female , Humans , Male , Medication Adherence/ethnology , Middle Aged , Rural Population , SARS-CoV-2/isolation & purification , Sex Factors , Veterans/psychology , Young Adult
4.
Clin Infect Dis ; 73(9): e3085-e3094, 2021 11 02.
Article in English | MEDLINE | ID: covidwho-1501024

ABSTRACT

BACKGROUND: Identifying risk factors for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection could help health systems improve testing and screening strategies. The aim of this study was to identify demographic factors, comorbid conditions, and symptoms independently associated with testing positive for SARS-CoV-2. METHODS: This was an observational cross-sectional study at the Veterans Health Administration, including persons tested for SARS-CoV-2 nucleic acid by polymerase chain reaction (PCR) between 28 February and 14 May 2020. Associations between demographic characteristics, diagnosed comorbid conditions, and documented symptoms with testing positive for SARS-CoV-2 were measured. RESULTS: Of 88 747 persons tested, 10 131 (11.4%) were SARS-CoV-2 PCR positive. Positivity was associated with older age (≥80 vs <50 years: adjusted odds ratio [aOR], 2.16 [95% confidence interval {CI}, 1.97-2.37]), male sex (aOR, 1.45 [95% CI, 1.34-1.57]), regional SARS-CoV-2 burden (≥2000 vs <400 cases/million: aOR, 5.43 [95% CI, 4.97-5.93]), urban residence (aOR, 1.78 [95% CI, 1.70-1.87]), black (aOR, 2.15 [95% CI, 2.05-2.26]) or American Indian/Alaska Native Hawaiian/Pacific Islander (aOR, 1.26 [95% CI, 1.05-1.52]) vs white race, and Hispanic ethnicity (aOR, 1.52 [95% CI, 1.40-1.65]). Obesity and diabetes were the only 2 medical conditions associated with testing positive. Documented fevers, chills, cough, and diarrhea were also associated with testing positive. The population attributable fraction of positive tests was highest for geographic location (35.3%), followed by demographic variables (27.1%), symptoms (12.0%), obesity (10.5%), and diabetes (0.4%). CONCLUSIONS: The majority of positive SARS-CoV-2 tests were attributed to geographic location, demographic characteristics, and obesity, with a minor contribution of chronic comorbid conditions.


Subject(s)
COVID-19 , SARS-CoV-2 , Aged , Cross-Sectional Studies , Delivery of Health Care , Humans , Male , Risk Factors , United States/epidemiology
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