When experiencing measles outbreaks in hospitals, the implementation of a 1-hour exposure window as opposed to the currently accepted 2-hour exposure window can adequately protect against secondary infections while simultaneously reducing pressure on healthcare personnel. This novel approach was testified by Wendy Berg, BSN, RN, CIC, the infection prevention manager at Children’s Minnesota during the annual meeting of the Association for Professionals in Infection Control and Epidemiology. The CDC’s traditional recommendation involved a 2-hour surveillance window, considering any individual present up to two hours post an infectious individual’s presence as exposed to measles.
The 2-hour window policy’s utility was tested in 2017 during a measles outbreak where the Children’s Minnesota staff tended to 52 measles patients. The total number of individals who were suspected to have been exposed to measles was nearly 700, out of which, 488 people received vaccination whereas 182 individuals remained susceptible. From these figures, nearly 146 were found eligible for post-exposure prophylaxis (PEP), and about 113 people got administered with PEP, as reported by Berg.
The 2017 outbreak witnessed two secondary measles cases: a hospital staff member who got previously vaccinated for measles, and a parent, who was assumed to be vaccinated previously but declined PEP. A remarkable deviation was noted in 2024 when the infection prevention staff shortened the exposure time window to just one hour.
During the 2024 outbreak that treated 46 measles patients, Children’s Minnesota identified not more than 300 individuals who were exposed, with 185 receiving vaccination and 97 remaining susceptible. Out the susceptible, 90 were found eligible and 45 received PEP. The similarity with the previous outbreak lies in the fact that two secondary cases appeared once again: a vaccinated employee, and a patient with outdated contact records. Wendy Berg highlighted that all secondary cases in both 2017 and 2024 had been in direct contact with a measles-positive patient.
She asserted that moving from a 2-hour to 1-hour exposure window did indeed lead to decreased pressure on the healthcare team, reduced instances of post-exposure prophylaxis administration, and prevented further disruption and stress for both patients and families. Additionally, despite the reduction in the exposure window, there was no surge in secondary measles cases.
On being questioned about any unexpected consequences of switching to a shortened window, Berg conveyed immense relief expressed by the Children’s Minnesota team. The more manageable workload enabled them with extra time to focus on process improvement, especially in clinics and emergency department waiting rooms. Berg added, institutions seeking to implement the 1-hour window must closely collaborate with their local and state health departments. Secondly, they must have a comprehensive understanding of ventilation and air exchange systems in their waiting areas, as inadequate ventilation might make a 1-hour window unfavorable.
Lastly, Berg advises providers on honing their focus during measles outbreaks, which includes lessening the number of susceptible individuals through MMR vaccination, having a robust front desk screening process, and incessant collaboration with local public health officials and infection prevention teams. For providers needing to prepare for future outbreaks, efforts must be directed towards response plan development and supporting vaccinations in under-vaccinated groups.
Source: https://www.healio.com/news/pediatrics/20250724/qa-should-measles-exposure-windows-be-1-hour-or-2