Epidemiology of hepatitis A in Ireland 2018 & 2019 data are provisional Niamh Murphy, May 2019

Hepatitis A virus Associated with poor hygiene and sanitation Virus shed in faeces and primarily transmitted from person-to-person via the faecal-oral route Common source outbreaks due to contaminated food or water also occur Incubation period (time from infection to symptoms) commonly 28-30 days (range 15-50) Period of Infectiousness - 2 weeks before until 1 week after onset of symptoms Acute disease – does not have a chronic form Lifelong immunity following infection Clinical severity tends to increase with age. Adults can experience severe illness lasting several months, whereas young children are frequently asymptomatic The most common symptoms are fever, loss of appetite, nausea, fatigue and abdominal pain, followed within a few days by jaundice In developed countries, hepatitis A is most commonly seen among travellers to endemic countries, household or sexual contacts of known cases, people who inject drugs (PWID) and men who have sex with men (MSM)

Hepatitis A vaccination Safe and effective vaccine Hepatitis A vaccine alone Combined hepatitis A and B vaccine Gives life-long protection Irish Immunisation Guidelines Vaccination recommended for travellers to endemic countries, people with chronic liver disease, PWID, MSM and close contacts of cases, among others https://www.hse.ie/eng/health/immunisation/hcpinfo/guidelines/ch8-hepatitis-a.pdf Free in STI clinics http://man2man.ie/stis/hepatitis-abc/ Student health services - may be a fee in some GP – vaccine is free, fee for administration If exposed, vaccination within 2 weeks is protective For sexually acquired cases of hepatitis A – STI testing and partner notification important

Number of notifications of hepatitis A in Ireland, and notification rate per 100,000 population, 2000-2018 2019 to date: 21 cases of hepatitis A notified 1st Jan – 20th May 2019

Hepatitis A notification rate per 100,000 population in Ireland, by HSE area, 2015-2018

Mean hepatitis A notification rates per 100,000 population in Ireland, by age group, 2004-2018 Key point: Rates generally highest in children and young to middle age adults, reflecting lack of immunity and travel

Hepatitis A notification rates per 100,000 population in Ireland, by sex, 2000-2018 Key point: Rates generally similar for males and females, except 2017 when there was an outbreak in MSM

Hepatitis A outbreaks in men who have sex with men (MSM) Hepatitis A not identified in MSM in Ireland prior to late 2016 Very large European-wide outbreak 2016-2018 About 4,500 cases in Europe, 20 in Ireland in 2017 Involved 3 strains of genotype IA hepatitis A: VRD_521_2016, RIVM-HAV16-090, V16-25801 Mostly male cases, and where known, mostly MSM Some spillover into general population 6 hepatitis A cases in MSM in Ireland, Jan 2018 - May 2019 European alerts issued 2019: 2 MSM clusters in Amsterdam, 1 in Vienna Pride events in Dublin and several other European countries over the summer Vaccination and good hygiene measures important

Hepatitis A notification rates per 100,000 population in Ireland, by sex and age group, 2017 Large European-wide outbreak in MSM – 20 Irish MSM cases + 10 additional cases associated with the outbreak

Summary of hepatitis A cases notified in Ireland in 2017 Increase in notifications, largely driven by European-wide outbreak in MSM 66 cases notified (1.4/100,000 population) 73% male (n=48, 2.0/100,000), 27% female (n=18, 0.7/100,000 population) Highest notification rates in adult males and children aged 5-9 years Country of infection: 33 outside Ireland, 30 Ireland, 3 unknown The most common countries of infection for travel associated cases were India, Spain, Pakistan, Germany & Romania Large European-wide outbreak in MSM 20 Irish MSM cases 13 MSM cases infected in Ireland, 6 outside of Ireland and country of infection was unknown for 1 10 additional cases were known contacts of MSM cases or were infected with an MSM outbreak strain of hepatitis A, but were not identified as MSM 5 other outbreaks with 10 associated cases were reported in 2017 The index case had travelled outside of Ireland for 3 of these outbreaks The other 2 outbreaks were family outbreaks, all associated cases infected in Ireland Remaining 26 cases: 17 associated with travel, 8 infected in Ireland, travel history unknown for 1

Hepatitis A notification rates per 100,000 population in Ireland, by sex and age group, 2018 Most cases travel related: 26 cases had a history of recent travel, 7 cases infected in Ireland, travel history not known for 2 cases Of the cases infected in Ireland, 4 were part of clusters where the index case had been infected outside Ireland

Summary of hepatitis A cases notified in Ireland in 2018 2018 was a more typical year than 2017 – a lot of travel associated cases of hepatitis A 35 cases notified (0.7/100,000 population) 60% male (n=21, 0.9 per 100,000), 40% female (n=14, 0.6 per 100,000) Highest notification rates in children and adults <45 years of age 86% of cases (n=30) were associated with travel outside Ireland (n=26), either directly or, in the case of outbreaks, via an index case infected outside Ireland (n=4) The most common countries of infection for travel associated cases were Brazil, Pakistan and India 4 outbreaks with 10 associated cases were reported in 2018 The index case had travelled outside of Ireland for all of these outbreaks Of the 7 cases infected in Ireland, 4 were linked to travel-associated outbreaks and 3 were sporadic cases Travel history was not known for 2 cases

Recent hepatitis A outbreaks due to frozen berries in Europe Very large European-wide outbreak, Jan 2013-Aug 2014 Linked to imported frozen berries About 1,500 confirmed and probable cases in 13 European countries, 23 in Ireland Genotype IA hepatitis A Outbreak in Sweden & Austria, June-Sept 2018 linked to imported frozen strawberries 17 confirmed cases in Sweden and 14 in Austria Genotype IB hepatitis A Outbreak in the Netherlands, March-May 2017 linked to frozen raspberry/blueberry mix imported from Bulgaria 14 cases Genotype IB hepatitis A - RIVM-HAV17-090 Strain of hepatitis A previously identified in Canadian outbreak associated with frozen berries Current advice from Food Safety Authority of Ireland “boil all imported frozen berries for at least one minute prior to consumption” https://www.fsai.ie/news_centre/boil_imported_frozen_berries_advice_23072018.html

Acknowledgements Departments of Public Health in all HSE areas: SPHMs, SMOs, Surveillance Scientists, IPCNs, Administration staff Notifiers: Laboratory Directors and their staff, and Clinicians Dr Paul McKeown, SPHM, HPSC Dr Lelia Thornton, SPHM in HPSC (retired 2018) Kirsty MacKenzie, PA to Director/Information Officer, HPSC