Browsing by Subject "Vaccine effectiveness"

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    Blue Notes
    (Elsevier, 2022) Kahi, Charles J.; Medicine, School of Medicine
    Comment on: doi: 10.1016/j.cgh.2022.02.030; doi: 10.1016/j.cgh.2021.12.032; doi: 10.1016/j.cgh.2021.06.020; doi: 10.1016/j.cgh.2021.11.031
  • Thumbnail Image
    Item
    BNT162b2 mRNA Vaccination Against Coronavirus Disease 2019 is Associated With a Decreased Likelihood of Multisystem Inflammatory Syndrome in Children Aged 5-18 Years-United States, July 2021 - April 2022
    (Oxford University Press, 2023) Zambrano, Laura D.; Newhams, Margaret M.; Olson, Samantha M.; Halasa, Natasha B.; Price, Ashley M.; Orzel, Amber O.; Young, Cameron C.; Boom, Julie A.; Sahni, Leila C.; Maddux, Aline B.; Bline, Katherine E.; Kamidani, Satoshi; Tarquinio, Keiko M.; Chiotos, Kathleen; Schuster, Jennifer E.; Cullimore, Melissa L.; Heidemann, Sabrina M.; Hobbs, Charlotte V.; Nofziger, Ryan A.; Pannaraj, Pia S.; Cameron, Melissa A.; Walker, Tracie C.; Schwartz, Stephanie P.; Michelson, Kelly N.; Coates, Bria M.; Flori, Heidi R.; Mack, Elizabeth H.; Smallcomb, Laura; Gertz, Shira J.; Bhumbra, Samina S.; Bradford, Tamara T.; Levy, Emily R.; Kong, Michele; Irby, Katherine; Cvijanovich, Natalie Z.; Zinter, Matt S.; Bowens, Cindy; Crandall, Hillary; Hume, Janet R.; Patel, Manish M.; Campbell, Angela P.; Randolph, Adrienne G.; Overcoming COVID-19 Investigators; Pediatrics, School of Medicine
    Background: Multisystem inflammatory syndrome in children (MIS-C), linked to antecedent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, is associated with considerable morbidity. Prevention of SARS-CoV-2 infection or coronavirus disease 2019 (COVID-19) by vaccination might also decrease MIS-C likelihood. Methods: In a multicenter, case-control, public health investigation of children ages 5-18 years hospitalized from 1 July 2021 to 7 April 2022, we compared the odds of being fully vaccinated (2 doses of BNT162b2 vaccine ≥28 days before hospital admission) between MIS-C case-patients and hospital-based controls who tested negative for SARS-CoV-2. These associations were examined by age group, timing of vaccination, and periods of Delta and Omicron variant predominance using multivariable logistic regression. Results: We compared 304 MIS-C case-patients (280 [92%] unvaccinated) with 502 controls (346 [69%] unvaccinated). MIS-C was associated with decreased likelihood of vaccination (adjusted OR [aOR]: .16; 95% CI: .10-.26), including among children ages 5-11 years (aOR: .22; 95% CI: .10-.52), ages 12-18 years (aOR: .10; 95% CI: .05-.19), and during the Delta (aOR: .06; 95% CI: .02-.15) and Omicron (aOR: .22; 95% CI: .11-.42) variant-predominant periods. This association persisted beyond 120 days after the second dose (aOR: .08; 95% CI: .03-.22) in 12-18-year-olds. Among all MIS-C case-patients, 187 (62%) required intensive care unit admission and 280 (92%) vaccine-eligible case-patients were unvaccinated. Conclusions: Vaccination with 2 doses of BNT162b2 is associated with reduced likelihood of MIS-C in children ages 5-18 years. Most vaccine-eligible hospitalized patients with MIS-C were unvaccinated.
  • Thumbnail Image
    Item
    Effectiveness of COVID-19 vaccines at preventing emergency department or urgent care encounters and hospitalizations among immunocompromised adults: An observational study of real-world data across 10 US states from August-December 2021
    (Elsevier, 2023) Embi, Peter J.; Levy, Matthew E.; Patel, Palak; DeSilva, Malini B.; Gaglani, Manjusha; Dascomb, Kristin; Dunne, Margaret M.; Klein, Nicola P.; Ong, Toan C.; Grannis, Shaun J.; Natarajan, Karthik; Yang, Duck-Hye; Stenehjem, Edward; Zerbo, Ousseny; McEvoy, Charlene; Rao, Suchitra; Thompson, Mark G.; Konatham, Deepika; Irving, Stephanie A.; Dixon, Brian E.; Han, Jungmi; Schrader, Kristin E.; Grisel, Nancy; Lewis, Ned; Kharbanda, Anupam B.; Barron, Michelle A.; Reynolds, Sue; Liao, I-Chia; Fadel, William F.; Rowley, Elizabeth A.; Arndorfer, Julie; Goddard, Kristin; Murthy, Kempapura; Valvi, Nimish R.; Weber, Zachary A.; Fireman, Bruce; Reese, Sarah E.; Ball, Sarah W.; Naleway, Allison L.; Medicine, School of Medicine
    Background: Immunocompromised (IC) persons are at increased risk for severe COVID-19 outcomes and are less protected by 1-2 COVID-19 vaccine doses than are immunocompetent (non-IC) persons. We compared vaccine effectiveness (VE) against medically attended COVID-19 of 2-3 mRNA and 1-2 viral-vector vaccine doses between IC and non-IC adults. Methods: Using a test-negative design among eight VISION Network sites, VE against laboratory-confirmed COVID-19-associated emergency department (ED) or urgent care (UC) events and hospitalizations from 26 August-25 December 2021 was estimated separately among IC and non-IC adults and among specific IC condition subgroups. Vaccination status was defined using number and timing of doses. VE for each status (versus unvaccinated) was adjusted for age, geography, time, prior positive test result, and local SARS-CoV-2 circulation. Results: We analyzed 8,848 ED/UC events and 18,843 hospitalizations among IC patients and 200,071 ED/UC events and 70,882 hospitalizations among non-IC patients. Among IC patients, 3-dose mRNA VE against ED/UC (73% [95% CI: 64-80]) and hospitalization (81% [95% CI: 76-86]) was lower than that among non-IC patients (ED/UC: 94% [95% CI: 93-94]; hospitalization: 96% [95% CI: 95-97]). Similar patterns were observed for viral-vector vaccines. Transplant recipients had lower VE than other IC subgroups. Conclusions: During B.1.617.2 (Delta) variant predominance, IC adults received moderate protection against COVID-19-associated medical events from three mRNA doses, or one viral-vector dose plus a second dose of any product. However, protection was lower in IC versus non-IC patients, especially among transplant recipients, underscoring the need for additional protection among IC adults.
  • Thumbnail Image
    Item
    Impact of accounting for correlation between COVID-19 and influenza vaccination in a COVID-19 vaccine effectiveness evaluation using a test-negative design
    (Elsevier, 2023) Payne, Amanda B.; Ciesla, Allison Avrich; Rowley, Elizabeth A. K.; Weber, Zachary A.; Reese, Sarah E.; Ong, Toan C.; Vazquez-Benitez, Gabriela; Naleway, Allison L.; Klein, Nicola P.; Embi, Peter J.; Grannis, Shaun J.; Kharbanda, Anupam B.; Gaglani, Manjusha; Tenforde, Mark W.; Link-Gelles, Ruth; VISION Network; Medicine, School of Medicine
    Test-negative-design COVID-19 vaccine effectiveness (VE) studies use symptomatic SARS-CoV-2-positive individuals as cases and symptomatic SARS-CoV-2-negative individuals as controls to evaluate COVID-19 VE. To evaluate the potential bias introduced by the correlation of COVID-19 and influenza vaccination behaviors, we assessed changes in estimates of VE of bivalent vaccines against COVID-19-associated hospitalizations and emergency department/urgent care (ED/UC) encounters when considering influenza vaccination status or including or excluding influenza-positive controls using data from the multi-state VISION vaccine effectiveness network. Analyses included encounters during October 2022 - February 2023, a period of SARS-CoV-2 and influenza cocirculation. When considering influenza vaccination status or including or excluding influenza-positive controls, COVID-19 VE estimates were robust, with most VE estimates against COVID-19-associated hospitalization and ED/UC encounters changing less than 5 percentage points. Higher proportions of influenza-positive patients among controls, influenza vaccination coverage, or VE could impact these findings; the potential bias should continue to be assessed.
  • Thumbnail Image
    Item
    Methods to Adjust for Confounding in Test-Negative Design COVID-19 Effectiveness Studies: Simulation Study
    (JMIR, 2025-01-27) Rowley, Elizabeth A. K.; Mitchell, Patrick K.; Yang, Duck-Hye; Lewis, Ned; Dixon, Brian E.; Vazquez-Benitez, Gabriela; Fadel, William F.; Essien, Inih J.; Naleway, Allison L.; Stenehjem, Edward; Ong, Toan C.; Gaglani, Manjusha; Natarajan, Karthik; Embi, Peter; Wiegand, Ryan E.; Link-Gelles, Ruth; Tenforde, Mark W.; Fireman, Bruce; Health Policy and Management, Richard M. Fairbanks School of Public Health
    Background: Real-world COVID-19 vaccine effectiveness (VE) studies are investigating exposures of increasing complexity accounting for time since vaccination. These studies require methods that adjust for the confounding that arises when morbidities and demographics are associated with vaccination and the risk of outcome events. Methods based on propensity scores (PS) are well-suited to this when the exposure is dichotomous, but present challenges when the exposure is multinomial. Objective: This simulation study aimed to investigate alternative methods to adjust for confounding in VE studies that have a test-negative design. Methods: Adjustment for a disease risk score (DRS) is compared with multivariable logistic regression. Both stratification on the DRS and direct covariate adjustment of the DRS are examined. Multivariable logistic regression with all the covariates and with a limited subset of key covariates is considered. The performance of VE estimators is evaluated across a multinomial vaccination exposure in simulated datasets. Results: Bias in VE estimates from multivariable models ranged from -5.3% to 6.1% across 4 levels of vaccination. Standard errors of VE estimates were unbiased, and 95% coverage probabilities were attained in most scenarios. The lowest coverage in the multivariable scenarios was 93.7% (95% CI 92.2%-95.2%) and occurred in the multivariable model with key covariates, while the highest coverage in the multivariable scenarios was 95.3% (95% CI 94.0%-96.6%) and occurred in the multivariable model with all covariates. Bias in VE estimates from DRS-adjusted models was low, ranging from -2.2% to 4.2%. However, the DRS-adjusted models underestimated the standard errors of VE estimates, with coverage sometimes below the 95% level. The lowest coverage in the DRS scenarios was 87.8% (95% CI 85.8%-89.8%) and occurred in the direct adjustment for the DRS model. The highest coverage in the DRS scenarios was 94.8% (95% CI 93.4%-96.2%) and occurred in the model that stratified on DRS. Although variation in the performance of VE estimates occurred across modeling strategies, variation in performance was also present across exposure groups. Conclusions: Overall, models using a DRS to adjust for confounding performed adequately but not as well as the multivariable models that adjusted for covariates individually.