CDC Systems for Reporting Norovirus

Key points

  • Learn about the different CDC systems used for reporting norovirus outbreaks by reviewing the table below.
  • 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.
Venn diagram on chalkboard.


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 due to healthcare-seeking behaviors and limited resources in health departments. 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 Reporting 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
Unit of Surveillance Outbreaks
  • Outbreaks
  • Individual cases
Outbreaks 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