Measles Surveillance in the United States: An Overview

Abstract

The elimination of endemic measles from the United States has been a national goal since the introduction of measles vaccine, and measles surveillance has been crucial to guide the elimination efforts. The United States surveillance system is geared towards detection of measles virus transmission, rapid discovery of measles outbreaks to facilitate outbreak control, and identification of risk factors for measles. The surveillance system is a passive reporting system that, when activated by a reported case of suspected measles, triggers a search for additional cases around the reported case. Cases are typically reported by health care providers or from schools and day care centers. The sensitivity of the system is increased through reporting and investigation of all suspected measles cases by means of an inclusive case definition (generalized maculopapular rash and fever), and the specificity is increased through laboratory testing for measles of all suspected cases.

Evaluation of the Measles Clinical Case Definition

“…The surveillance of measles is based on a case classification system that identifies suspected, probable, and confirmed cases [1]. Any person with a generalized maculopapular rash and fever is considered to have a suspected case.…”

Measles outbreaks in high schools closely associated with sporting events in Niigata, Japan

“…20,21 The National Epidemiological Surveillance of Infectious Diseases program of the Ministry of Health, Labor and Welfare in Japan is numbers of patients clinically diagnosed with measles have been reported on a weekly basis from 3000 sentinel pediatricians/general physicians throughout Japan. In the present comparison of Infectious Disease Surveillance data and mandatory measles case reports from high schools, the former did not reflect the actual epidemiological conditions, such as patient numbers and duration of the outbreak.…”

Has Surveillance Been Adequate to Detect Endemic Measles in the United States?

“…National surveillance data are based on demographic, clinical, and epidemiological case information that is reported to the National Notifiable Diseases Surveillance System, Centers for Disease Control and Prevention (CDC). Additional information is collected on the measles virus genotype from the case, on the basis of testing done by the CDC Measles Virus Laboratory [1,5,6].…”

“…A confirmed case of measles is defined as any suspected case that is confirmed by appropriate laboratory testing or a case that meets the clinical case definition and is epidemiologically linked to a laboratory-confirmed case [1]. Cases that are epidemiologically linked to each other are defined as a chain of transmission; an isolated case constitutes a chain of transmission in which a single case is detected (i.e., unlinked to any other case), and an outbreak of 10 cases also constitutes a chain of transmission.…”

“…Cases that are epidemiologically linked to each other are defined as a chain of transmission; an isolated case constitutes a chain of transmission in which a single case is detected (i.e., unlinked to any other case), and an outbreak of 10 cases also constitutes a chain of transmission. Cases among persons who were outside the country during the 21 days before rash onset are classified as international importations [1].…”