Surveillance Webinar: Measles Outbreak and Response-Surveillance Webinar: Measles Outbreak and Response PPT

Surveillance Webinar: Measles Outbreak and Response PPT

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This webinar, presented by Marco Tori (SC Department of Public Health/CDC) on March 19, 2026, reviews measles epidemiology, outbreak control, and surveillance during the 2025–26 South Carolina measles outbreak. Measles is a highly contagious airborne paramyxovirus infection; virus-laden aerosols can remain suspended for up to two hours. Typical incubation is ~8–12 days to prodrome and about 14 days to rash, and people are infectious from four days before through four days after rash onset. With an R0 of 12–18 and household secondary attack rates near 90% among susceptibles, very high vaccination coverage is required for herd protection. Beyond the characteristic rash, measles can cause otitis media, diarrhea, pneumonia, encephalitis, death, and rare late SSPE; it can also produce “immune amnesia,” increasing vulnerability to other infections.<br /><br />The talk emphasizes adapting surveillance as an outbreak evolves. In non-outbreak settings, measles is immediately reportable and relies heavily on provider calls plus passive laboratory reporting (IgM/IgG, PCR), though delays are a key limitation. Early in an outbreak, the priority is high sensitivity: educate clinicians and the public, simplify testing, and build communication channels so all plausible cases are tested. During ongoing transmission, surveillance aims to capture as many cases as possible, define at-risk groups and geographies, refine testing algorithms, and track trends using percent positivity and epi-curves, while assessing reporting delays (rash onset vs confirmation). As outbreaks wane, active surveillance expands and can incorporate wastewater and syndromic systems; wastewater detection can signal transmission even without reported cases.<br /><br />Control strategies focus on breaking transmission chains through case isolation (including airborne isolation in hospitals), contact quarantine/exclusion based on immunity status, and enhanced healthcare-facility rules for exposed non-immune staff. Modeling suggests isolation alone is insufficient; vaccination is central. The presentation reviews vaccination approaches (ring, geographic, mass, boosters, risk-based), including an SC campaign giving ~4,800 early MMR doses to infants 6–11 months (who still need the routine two-dose series after age 1). Effective risk communication should be transparent, non-stigmatizing, consistent, and action-oriented. Finally, it clarifies governmental roles (state leads; federal provides resources/technical assistance) and notes U.S. measles elimination (achieved in 2000) is threatened in 2025–26 amid ~2,000 U.S. cases and the risk of sustained transmission lasting 12 months.

Keywords

measles epidemiology

South Carolina measles outbreak 2025-2026

outbreak control measures

measles surveillance strategies

airborne transmission aerosols

MMR vaccination campaign

ring vaccination and mass vaccination

case isolation and contact quarantine

wastewater surveillance for measles

measles elimination threatened in US