CDC Reports Highest Number of Measles Cases Since 1996

June 23, 2011

According to a May 27, viagra 40mg 2011 report from the Centers for Disease Control and Prevention (CDC), the United States is experiencing its highest number of reported measles cases since 1996.

Measles is an acute viral illness. It is highly contagious, and can lead to serious complications and death. After exposure, up to 90% of susceptible individuals will develop measles.

See related HAI focus article: Prevention of Measles Transmission in Healthcare Settings: Indiana Issues Measles Infection Control Recommendations

During the years of 2001 to 2008, a median of 56 measles cases were annually reported to the CDC (ranging from 37 to 140 cases). In contrast, during the first 19 weeks of this year (2011), 118 cases of measles have already been reported. This is the highest number reported for this period since 1996.

Measles cases are reported by state health departments to CDC, and confirmed cases are reported via the National Notifiable Disease Surveillance System (NNDSS) using standard case definitions (3). Cases are considered internationally imported if at least some of the exposure period (7–21 days before rash onset) occurred outside the United States and rash occurred within 21 days of entry into the United States, with no known exposure to measles in the United States during that time. Import-associated cases include 1) internationally imported cases; 2) cases that are related epidemiologically to imported cases; and 3) imported virus cases for which an epidemiologic link has not been identified but the viral genotype detected suggests recent importation.* Laboratory confirmation of measles is made by detection in serum of measles-specific immunoglobulin M antibodies, isolation of measles virus, or detection of measles virus RNA by nucleic acid amplification in an appropriate clinical specimen (e.g., nasopharyngeal/oropharyngeal swabs, nasal aspirates, throat washes, or urine). For this report, persons with reported unknown or undocumented vaccination status are considered unvaccinated. An outbreak of measles is defined as a chain of transmission with three or more confirmed cases.

The CDC noted the following facts about the 118 infected individuals:

  • The 118 cases were reported from 23 different U.S. states.
  • The age of patients ranged from 3 months to 67 years.
  • Laboratory confirmation was obtained for 105 (89%) of the cases.
  • Measles virus RNA was detected in 52 (44% of the cases).
  • 105 (89%) of the cases were imported from other countries.
  • Of the 118 cases, 105 (89%) were not vaccinated against the virus.
  • Forty-seven (40%) of the patients had to be hospitalized.
  • Nine individuals had pneumonia.
  • None of the patients exhibited encephalitis.
  • None of the patients died.
  • A total of 9 outbreaks accounted for 58 (49%) of the 118 reported cases. The median size of these outbreaks was 4 cases (ranging from 3 to 21).
  • The largest outbreak occurred in Minnesota.

According to the CDC, the increased numbers of importations of measles cases underscores the need for vaccinations to prevent measles and its associated complications.

Reference: Centers for Disease Control and Prevention. Measles — United States, January –May 20, 2011. Morbidity and Mortality Weekly Report, 60(20):666-668 (May 27, 2011).

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