CaliciNet Data – Norovirus US Outbreak Map

Number of Confirmed Norovirus Outbreaks
Submitted to CaliciNet by State

September 1, 2021 – March 31, 2022

Number of Confirmed Norovirus Outbreaks
Submitted to CaliciNet, by Genogroup

September 1, 2020 – April 30, 2022

Genotype Distribution of Norovirus Outbreaks

September 1, 2021 – April 30, 2022 (n=223)

* Percent of total number of outbreaks shown in bar chart for each genotype category

The Other Genotypes category includes genotypes from outbreaks that each make up less than 5% of the total number of outbreaks.

Genotype Distribution of Norovirus Outbreaks, previous year
Genotype	Number of Outbreaks
GII.4 Sydney[P16]	98
GII.3[P12]	19
GI.6[P7]	15
Other Genotype	91

Genotype Distribution of Norovirus Outbreaks, previous year
Genotype	Number of Outbreaks
GII.4 Sydney[P16]	88
GII.2[P16]	15
GII.6[P7]	11
GII.10[P16]	11
GIX.1[GII.P15]	11
Other Genotype	33

* Dual typing for norovirus is being implemented by laboratories participating in CaliciNet. Dual typing is RT-PCR amplification of a partial region of both the polymerase gene and the capsid gene (region B-C) in a single reaction for genogroup I or genogroup II noroviruses.

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Page last reviewed: May 9, 2022

Content source: National Center for Immunization and Respiratory Diseases, Division of Viral Diseases