Hepatitis A Outbreak in Ontario

Public Health Ontario, in collaboration with partners, continues to investigate an ongoing outbreak of hepatitis A in Ontario; outbreak cases have the same genotype (1A) and genetic sequence (VRD_521_2016).

  • This outbreak sequence circulated in 2016 and 2017 in outbreaks in the United Kingdom and Europe that mostly affected men who have sex with men (MSM).  
  • Cases linked to the outbreak in Ontario were first detected in June 2017 and have since been reported in a number of local health units. 
  • Reported risk factors suggest person-to-person spread and include drug use, sex with same sex among males, homelessness/under-housed and less frequently, incarceration.

On average, approximately 100 hepatitis A cases are reported in Ontario each year. In 2017 and 2018 combined, a total of 317 cases were reported. This number includes 134 outbreak-associated cases that were identified between June 2017 and December 2018. The number of non-outbreak cases is within the expected range.

Number of outbreak-confirmed Hepatitis A cases reported in Ontario from June 1, 2017 to December 31, 2018

Graph illustrating hepatitis A outbreaks in Ontario.

Source: Ontario Ministry of Health and Long-Term Care, integrated Public Health Information System (iPHIS) database, extracted by Public Health Ontario [2019/01/15].

Note: Case counts are  subject to change due reporting delays and the long incubation period of up to 50 days.


Chat icon

Contact the Department

Enteric, Zoonotic and Vector-Borne Diseases


Updated 8 April 2019