Investigation of a Severe Acute Respiratory Syndrome Coronavirus 2 Delta (B.1.617.2) Variant Outbreak Among Residents of a Skilled Nursing Facility and Vaccine Effectiveness Analysis: Maricopa County, Arizona, June–July 2021. (12th April 2022)

• Record Type: Journal Article
• Authors: Dale, Ariella P; Almendares, Olivia; Howard, Brandon J; Burnett, Eleanor; Prasai, Siru; Arons, Melissa; Collins, Jennifer; Duffy, Nadezdha; Pandit, Urvashi; Brady, Shane; White, Jessica R; Garrett, Brenna; Kirking, Hannah L; Sunenshine, Rebecca; Tate, Jacqueline E; Scott, Sarah E
• Is Part Of: Clinical infectious diseases. Volume 75:Number 1(2022)
• Page Start: e20
• Page End: e26
• Publication Date: 2022-04-12
• Subjects: COVID-19 -- skilled nursing facility -- delta variant -- outbreak -- local public health; Communicable diseases -- Periodicals; 616.905
• DOI: 10.1093/cid/ciac240
• Languages: English
• ISSNs: 1058-4838

Abstract

Abstract: Background: Short-term rehabilitation units present unique infection control challenges because of high turnover and medically complex residents. In June 2021, the Maricopa County Department of Public Health was notified of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Delta outbreak in a skilled nursing facility short-term rehabilitation unit. We describe the outbreak and assess vaccine effectiveness (VE). Methods: Facility electronic medical records were reviewed for residents who spent > 1 night on the affected unit between June 10 and July 23, 2021, to collect demographics, SARS-CoV-2 test results, underlying medical conditions, vaccination status, and clinical outcomes. Coronavirus disease 2019 VE estimates using Cox proportional hazards models were calculated. Results: Forty (37%) of 109 short-stay rehabilitation unit residents who met inclusion criteria tested positive for SARS-CoV-2. SARS-CoV-2-positive case-patients were mostly male (58%) and White (78%) with a median age of 65 (range, 27-92) years; 11 (27%) were immunocompromised. Of residents, 39% (10 cases, 32 noncases) received 2 doses and 9% (4 cases, 6 noncases) received 1 dose of messenger RNA (mRNA) vaccine. Among nonimmunocompromised residents, adjusted 2-dose primary-series mRNA VE against symptomatic infection was 80% (95% confidence interval, 15-95). More cases were hospitalized (33%) or died (38%) than noncases (10% hospitalized; 16% died). Conclusions: In this large SARS-CoV-2 Delta outbreak in a high-turnover short-term rehabilitation unit, a low vaccination rate and medically complex resident population were noted alongside severe outcomes. VE of 2-dose primary-series mRNA vaccine against symptomatic infection was the highest in nonimmunocompromised residents. Health departments can use vaccine coverage data to prioritize facilities for assistance in preventing outbreaks. Abstract : A severe acute respiratory syndrome coronavirus 2 Delta variant outbreak investigation in a short-term rehabilitation unit found a low vaccination rate and a medically complex resident population. Estimated vaccine effectiveness against symptomatic infection was the highest in nonimmunocompromised residents' primary-vaccine series with a messenger RNA vaccine.