CDC updates norovirus guidelines

CDC. MMWR. 2011;60:1-15.

The CDC has issued updated guidelines for effective prevention and control of norovirus infection in response to substantial advances in norovirus epidemiology, immunology, diagnostic methods and infection control measures. The new guidelines, published in the Morbidity and Mortality Weekly Report, expand and revise the norovirus guidelines for outbreak management and disease prevention from 2001.

The updated recommendations were developed based on critical review of published literature and unpublished data from outbreak investigations. These guidelines provide general principles for recommendations across all outbreak settings and correlate with other state and local regulatory guidance, including the CDC Healthcare Infection Control Practices Advisory Committee (HICPAC) and the model FDA Food Code.

New recommendations state that hand hygiene is likely the most effective prevention measure against norovirus infection. Also included is the standardized collection of clinical specimens during norovirus outbreaks, environmental disinfection, exclusion and isolation of infected individuals, and the use of two recently launched surveillance systems for reporting norovirus outbreaks: The National Outbreak Reporting System (NORS) and CaliciNet.

According to background data in the report, most norovirus outbreaks are primarily associated with person-to-person transmission. In addition, increases in norovirus outbreaks are associated with the emergence of new genogroup II, type 4 strains that evade population immunity and can be transmitted by food, water, contaminated environmental surfaces and person-to-person transmission.

“As molecular diagnostic techniques have improved in performance and become more widely available, detection and reporting of norovirus outbreaks have increased. Although the inability to culture human noroviruses in vitro has hampered progress, assessment of the performance of disinfectants has been facilitated by the discovery of new, cultivable surrogates for human noroviruses,” CDC officials wrote.

The updated guidelines can be viewed and downloaded at www.cdc.gov/mmwr/pdf/rr/rr6003.pdf. – by Ashley DeNyse

There are important reasons to understand the principles of outbreak management and disease prevention of noroviruses. This group of Caliciviridae viruses is the most common cause of foodborne disease in the United States. Noroviruses are infectious at very low inoculum size and are moderately resistant to disinfection. Once contaminating an environment such as a cruise ship or nursing home, they are hard to eradicate. The guidelines and perspective on noroviruses developed by the CDC are important for most in infectious diseases to review.

–Herbert DuPont, MD

Chair in the department of medicine at Baylor College of Medicine,
chief of medicine at St. Luke’s Episcopal Hospital, Houston

Disclosure: Dr. DuPont reports no relevant financial disclosures.

Follow the PediatricSuperSite.com on Twitter.