TY - JOUR T1 - Effectiveness of a Third Dose of mRNA Vaccines Against COVID-19-Associated Emergency Department and Urgent Care Encounters and Hospitalizations Among Adults During Periods of Delta and Omicron Variant Predominance - VISION Network, 10 States, August 2021-January 2022. AU - Thompson,Mark G, AU - Natarajan,Karthik, AU - Irving,Stephanie A, AU - Rowley,Elizabeth A, AU - Griggs,Eric P, AU - Gaglani,Manjusha, AU - Klein,Nicola P, AU - Grannis,Shaun J, AU - DeSilva,Malini B, AU - Stenehjem,Edward, AU - Reese,Sarah E, AU - Dickerson,Monica, AU - Naleway,Allison L, AU - Han,Jungmi, AU - Konatham,Deepika, AU - McEvoy,Charlene, AU - Rao,Suchitra, AU - Dixon,Brian E, AU - Dascomb,Kristin, AU - Lewis,Ned, AU - Levy,Matthew E, AU - Patel,Palak, AU - Liao,I-Chia, AU - Kharbanda,Anupam B, AU - Barron,Michelle A, AU - Fadel,William F, AU - Grisel,Nancy, AU - Goddard,Kristin, AU - Yang,Duck-Hye, AU - Wondimu,Mehiret H, AU - Murthy,Kempapura, AU - Valvi,Nimish R, AU - Arndorfer,Julie, AU - Fireman,Bruce, AU - Dunne,Margaret M, AU - Embi,Peter, AU - Azziz-Baumgartner,Eduardo, AU - Zerbo,Ousseny, AU - Bozio,Catherine H, AU - Reynolds,Sue, AU - Ferdinands,Jill, AU - Williams,Jeremiah, AU - Link-Gelles,Ruth, AU - Schrag,Stephanie J, AU - Verani,Jennifer R, AU - Ball,Sarah, AU - Ong,Toan C, Y1 - 2022/01/21/ PY - 2022/1/27/entrez PY - 2022/1/28/pubmed PY - 2022/2/8/medline SP - 139 EP - 145 JF - MMWR. Morbidity and mortality weekly report JO - MMWR Morb Mortal Wkly Rep VL - 71 IS - 4 N2 - Estimates of COVID-19 mRNA vaccine effectiveness (VE) have declined in recent months (1,2) because of waning vaccine induced immunity over time,* possible increased immune evasion by SARS-CoV-2 variants (3), or a combination of these and other factors. CDC recommends that all persons aged ≥12 years receive a third dose (booster) of an mRNA vaccine ≥5 months after receipt of the second mRNA vaccine dose and that immunocompromised individuals receive a third primary dose.† A third dose of BNT162b2 (Pfizer-BioNTech) COVID-19 vaccine increases neutralizing antibody levels (4), and three recent studies from Israel have shown improved effectiveness of a third dose in preventing COVID-19 associated with infections with the SARS-CoV-2 B.1.617.2 (Delta) variant (5-7). Yet, data are limited on the real-world effectiveness of third doses of COVID-19 mRNA vaccine in the United States, especially since the SARS-CoV-2 B.1.1.529 (Omicron) variant became predominant in mid-December 2021. The VISION Network§ examined VE by analyzing 222,772 encounters from 383 emergency departments (EDs) and urgent care (UC) clinics and 87,904 hospitalizations from 259 hospitals among adults aged ≥18 years across 10 states from August 26, 2021¶ to January 5, 2022. Analyses were stratified by the period before and after the Omicron variant became the predominant strain (>50% of sequenced viruses) at each study site. During the period of Delta predominance across study sites in the United States (August-mid-December 2021), VE against laboratory-confirmed COVID-19-associated ED and UC encounters was 86% 14-179 days after dose 2, 76% ≥180 days after dose 2, and 94% ≥14 days after dose 3. Estimates of VE for the same intervals after vaccination during Omicron variant predominance were 52%, 38%, and 82%, respectively. During the period of Delta variant predominance, VE against laboratory-confirmed COVID-19-associated hospitalizations was 90% 14-179 days after dose 2, 81% ≥180 days after dose 2, and 94% ≥14 days after dose 3. During Omicron variant predominance, VE estimates for the same intervals after vaccination were 81%, 57%, and 90%, respectively. The highest estimates of VE against COVID-19-associated ED and UC encounters or hospitalizations during both Delta- and Omicron-predominant periods were among adults who received a third dose of mRNA vaccine. All unvaccinated persons should get vaccinated as soon as possible. All adults who have received mRNA vaccines during their primary COVID-19 vaccination series should receive a third dose when eligible, and eligible persons should stay up to date with COVID-19 vaccinations. SN - 1545-861X UR - https://www.unboundmedicine.com/medline/citation/35085224/Effectiveness_of_a_Third_Dose_of_mRNA_Vaccines_Against_COVID_19_Associated_Emergency_Department_and_Urgent_Care_Encounters_and_Hospitalizations_Among_Adults_During_Periods_of_Delta_and_Omicron_Variant_Predominance___VISION_Network_10_States_August_2021_January_2022_ DB - PRIME DP - Unbound Medicine ER -