81 - Investigation of Varicella Outbreaks Among Recent Migrants in New York City, 2022

Poster Number: 81
Publication Number: 81.149

Krishika Graham, NYC Department of Health and Mental Hygiene, Queens, NY, United States; Robert J. Arciuolo, NYC DOHMH, Long Island City, NY, United States; Olivia Matalka, New York City Department of Health and Mental Hygiene, New York, NY, United States; Beth M. Isaac, New York City Department of Health and Mental Hygiene, Long Island City, NY, United States; Leah Seifu, NYC Department of Health and Mental Hygiene, New York, NY, United States; John Croft, New York City Department of Health and Mental Hygiene, Long Island City, NY, United States; Antonine Jean, New York City Department of Health and Mental Hygiene, Bureau of Immunization, Long Island City, NY, United States; Noora Majid, New York City Department of Health and Mental Hygiene, New York, NY, United States; Michelle Macaraig, NYC DOHMH, Long Island City, NY, United States; Erica Silverman, New York City Health & Hospitals, New York, NY, United States; Fabienne Laraque, NYC Department of Homeless Services, New York, NY, United States; Alyssa Bouscaren, DHS, New York, NY, United States; Bindy L. Crouch, NYC Department of Health and Mental Hygiene, Long Island City, NY, United States; Jennifer Rosen, NYC DOHMH, Long Island City, NY, United States

Background: On October 13, 2022, the New York City (NYC) Health Department (DOHMH) identified a cluster of individuals with varicella in a residential facility primarily among people who recently migrated from Central and South America. Varicella is a viral infection characterized by a generalized, pruritic, vesicular rash. While most with varicella recover, serious complications can occur. Varicella vaccination coverage varies by country. In the United States, routine childhood vaccination includes varicella vaccine, and two doses are required to attend NYC schools.

Objective: To describe a varicella outbreak response.

Design/Methods: Individuals with suspected varicella infections were reported to DOHMH by residential facilities, schools, and healthcare facilities. Coordinating with these settings, DOHMH investigations included patient interview, medical and immunization record review, and identifying settings attended during incubation or infectious period. Individuals with a clinically compatible rash and either provider diagnosis or known exposure to an individual with varicella were counted as cases. Ongoing control measures include isolation of infectious cases, identification and quarantine of non-immune contacts, and ensuring compliance with immunization requirements in schools, including supporting vaccination efforts. Varicella vaccination was recommended for individuals without evidence of immunity.

Results: As of December 31, 2022, there have been 140 cases of varicella linked to 9 residential facilities and 22 schools. Rash onset was from 9/30/2022-12/31/2022. The median age of cases was 10 years (range: 1 month to 43 years), including 22 (15.7%) < 4 years, 93 (66.4%) 4-18 years, and 25 (17.9%) ≥19 years. Case counts at the 9 facilities ranged from 1 to 104. Of all 140 cases, 9 (6.4%) acquired infection prior to NYC arrival. 50 (35.7%) attended school while infectious (N=21 schools). 135 (96.4%) did not have documentation of varicella-containing vaccine prior to infection. 5 (3.6%) cases were hospitalized with varicella complications. Varicella vaccination efforts and outreach have been underway at residential facilities with >1 case (N=5 facilities), which range in size from 237 to 3,500 residents.

Conclusion(s): This ongoing varicella outbreak has been propagated by exposures in schools and residential facilities. Vaccination upon arrival to NYC among migrant children without documentation of varicella immunity is critical to prevent future outbreaks in these facilities. Additionally, ensuring compliance with routine school immunization requirements is important for reducing exposures in schools.