Challenging 21-day quarantine guidelines for mumps in Beijing: Data-driven recommendations for a high-coverage MMR vaccination era (2019-2024).

Mumps is a vaccine-preventable disease. Following Beijing's implementation of a three-dose MMR vaccination strategy, incidence rates declined significantly. However, the current 21-d quarantine period lacks evidence-based support, resulting in low compliance and conflicts between healthcare providers and patients. This study analyzed 2019-2024 surveillance data to characterize mumps in the vaccine era through viral shedding detection. Study participants were NNDRS-reported mumps cases with both registered and collective residences in Beijing's Chaoyang District, who signed informed consent for shortened isolation surveillance. Data were integrated from three sources: 1) National Notifiable Disease Reporting System cases; 2) Beijing's immunization registry; and 3) epidemiological/laboratory records. PCR and/or serology-confirmed cases (Chaoyang CDC) were analyzed for demographics, clinical features, and vaccination history. Quarantine clearance was based on test results. From 2005 to 2024, 8,070 mumps cases were reported in Chaoyang District (average annual incidence: 12.69/100,000), showing a downward trend. Among 146 cases (2019-2024), 95.89% were childcare/school attendees; 141 received ≥1 MMR dose. All cases presented parotid swelling (duration: 1-12 d, 97.26% ≤9 d), with no complications. Of the 526 samples, 4 tested PCR-positive, 6 IgM-positive, and 18 IgG-confirmed. Quarantine was safely reduced from 21 to 9 d in 88.36% (129/146) of cases without increasing outbreak risks. The 21-d quarantine standard is outdated due to evolving epidemiological patterns. Recommendations include adopting molecular diagnostic criteria, validating a ≤5-d quarantine via multicenter studies, and establishing dynamic vaccine efficacy monitoring for targeted prevention.