Reporting and Surveillance for Norovirus

To report a norovirus outbreak, contact your state or local health department.


Currently, state, local, and territorial health departments are not required to report individual cases of norovirus illness to CDC. We may not know about many cases because people may not seek healthcare for their illness and most hospitals and doctor’s offices do not generally test for norovirus.

Healthcare providers should report all outbreaks of acute gastroenteritis, including suspected outbreaks of norovirus, to the appropriate state, local, or territorial health department.

Health departments are encouraged to report all suspected and confirmed norovirus outbreaks through the National Outbreak Reporting System (NORS) and CaliciNet.

CDC Reporting Systems

CDC Norovirus Surveillance Systems
Year Launched 2009 2009 2012 1989 2018
Type of System National web-based platform National network of public health laboratories Network of state health departments that work with CDC National laboratory-based system Network of state health departments that work with CDC
Purpose Integrate and streamline previous outbreak reporting systems Help CDC compare different norovirus genotypes, link outbreaks to a common source, monitor circulating genotypes, and identify new ones Improve timeliness, completeness, and consistency of norovirus outbreak reporting, and quickly assess current norovirus activity, past activity, and impact of future norovirus genotypes Timely monitor temporal and geographic circulation patterns of cases of select viruses Encourage laboratories within jurisdictions to participate and improve reporting of diagnostic results for select viruses to NREVSS
Types of Cases Included Outbreak-associated cases
  • Outbreak-associated cases
  • Individual cases
Outbreak-associated cases Individual cases Individual cases
Viral Disease of Focus
  • All enteric illness outbreaks (including those caused by norovirus)
  • Non-enteric illness outbreaks spread through food and water
  • Certain fungal disease outbreaks
Norovirus Norovirus
  • Norovirus
  • Rotavirus
  • Enteric adenovirus
  • Respiratory adenovirus
  • Coronavirus
  • Human metapneumovirus
  • Human parainfluenza virus
  • Respiratory syncytial virus
  • Norovirus
  • Rotavirus
  • Enteric adenovirus
Type of Data Collected Aggregate clinical and epidemiological data, including date and location of the outbreak, # of people who became ill and their symptoms, and the pathogen that caused the outbreak. Genotype information for norovirus, basic epidemiological data, such as transmission route and outbreak location and patient demographic data. A minimum set of epidemiological and laboratory data reported to NORS

Genotype information uploaded to CaliciNet.

Total # of weekly laboratory tests performed for the seven viruses, the method used for detection, and # of those tests with positive results. Same type of laboratory data that NREVSS collects.
Genotype information for specimens sequenced at public health laboratories.
Relationship to Other Norovirus Systems NORS obtains norovirus genotype data from CaliciNet. CaliciNet data linked to NORS to provide genotype information NoroSTAT combines a subset of NORS and CaliciNet data. NREVSS participation increased through NREVSS Enhanced. NREVSS Enhanced increases laboratory participation in NREVSS.
Who Reports (Source of Data) State, local, and territorial health departments Federal, state, and local public health laboratories who complete a CaliciNet certification, or who partners with a certified CaliciNet Outbreak Support Center (CN-OSCs). 15 participating state health departments (AL, CO, MA, MI, MN, NE, NM, NC, OH, OR, SC, TN, VA, WI, and WY) Clinical and state laboratories
See list of participating labs
8 participating state health departments (IN, MI, MN, NE, NM, OR, TN, WI)
How to Report Outbreak data entered into an online interface Lab data electronically uploaded to a national database. Suspected and confirmed norovirus outbreaks reported to CDC through NORS and CaliciNet within 7 days of outbreak notice. Data electronically submitted to CDC. Data electronically submitted to CDC.
Data Dissemination Updated once a year on CDC’s NORS Dashboard.
For more information, contact
Updated monthly on CDC’s CaliciNet Data webpage. Updated monthly on CDC’s NoroSTAT Graph and Data Table. Updated weekly on CDC’s National Respiratory and Enteric Virus Surveillance System. N/A
Additional Information NORS CaliciNet NoroSTAT NREVSS N/A

Notes About the Data

  • Norovirus data reported to CDC are voluntary.
  • NORS Dashboard does not contain all data fields reported through NORS.
  • Norovirus outbreaks and cases are likely underreported due to healthcare-seeking behaviors and limited resources in health departments.

Surveillance Systems

In addition to collecting norovirus outbreak data from state and local health departments, CDC uses the following platforms to generate estimates of norovirus illness and monitor trends over time.

NVSN: New Vaccine Surveillance Network (NVSN) includes study sites that conduct active, population-based surveillance for hospitalizations and outpatient visits associated with acute gastroenteritis in children, as well as surveillance for acute respiratory illness.

SUPERNOVA: The Surveillance Platform for Enteric and Respiratory Infectious Organisms at the VA (SUPERNOVA) is a network of five Veterans Affairs Medical Centers (VAMCs) in the United States that conduct active and passive surveillance for acute gastroenteritis, with laboratory-confirmed testing of various pathogens, including norovirus. SUPERNOVA is an endemic disease surveillance system that provides data to estimate the prevalence and incidence of norovirus in adults. Ongoing surveillance using this platform will allow for characterization of the pathogen distribution and serologic response over time.

NoroSurv: NoroSurv is a global pediatric norovirus strain surveillance network. The aim of the network is to collect data on the circulating norovirus genotypes in hospitalized children under 5 years of age across different countries and continents. NoroSurv uses the most recent dual [polymerase (P) and capsid (C)] typing nomenclature for norovirus strains. Participating laboratories use standardized protocols for norovirus dual typing to generate P and C types.