Epidemiology of hepatitis B in Ireland Last updated March 2017

Hepatitis B virus (HBV) (1) Hepatitis B is a viral infection, which causes inflammation of the liver It is transmitted through contact with semen, blood or other body fluids from an infected person Most common means of transmission: unprotected sex, sharing needles when injecting drugs, from mother to baby around the time of birth Less common means of transmission: unscreened blood or blood products (outside Ireland), accidental needlestick/blood exposure in healthcare settings, household/close contact particularly in early childhood, sharing razors or toothbrushes 50-100 times more infectious than HIV Incubation period (time from infection to onset symptoms) is 6 weeks to 6 months, average 2-3 months

Hepatitis B virus (HBV) (2) Acute (new infection): <10% children and 30-50% adults develop symptoms when first infected Symptoms include: loss appetite, nausea, vomiting, abdominal discomfort, joint pain, fever, fatigue, dark urine, pale stools, jaundice Chronic (long-term) infection develops in 80-90% of those infected as infants, 30-50% of children <6 years and <10% of those infected as adults Chronic infection can lead to chronic liver disease, cirrhosis, liver cancer or liver failure, usually over 20-30+ years World Health Organization (WHO) estimates that approximately 240 million people are chronically infected worldwide Vaccine preventable – universal infant vaccination introduced in Ireland in 2008. Vaccine also recommended for high risk groups

Worldwide prevalence hepatitis B (Source: CDC http://www. cdc

Number of notifications of hepatitis B, 1997-2016 Hepatitis B notifications increased steeply between 2000 and 2008 This was mostly attributable to large numbers of people migrating to Ireland from hepatitis B endemic countries, with chronic hepatitis B infections. Immigration to Ireland has decreased in recent years, correlating with a reduction in hepatitis B notifications. However, there was a 24% increase in notifications in 2015 compared to 2014, notifications are slightly lower year to date in 2016 (mid-October) Notifications of chronic cases (long-term infections) peaked in 2008 (n=769). 502 chronic cases were notified in 2015 (35% decrease compared to peak levels) The number of acute cases (new infections) notified has generally been low, but has also decreased in recent years. Notifications of acute cases peaked in 2006 (n=95). 26 acute cases of hepatitis B were notified in 2015 (73% decrease compared to peak levels)

Hepatitis B notification rates per 100,000 population, by HSE area, 2004-2016 Highest rates in the HSE-E

Trends in acute hepatitis B notifications by sex and median age, 2004-2016

Mean annual notification rates per 100,000 for acute cases of hepatitis B by age and sex, 2004-2016

Notification rates per 100,000 for acute cases of hepatitis B by age and sex, 2016

Trends in chronic hepatitis B notifications by sex and median age, 2004-2016

Mean annual notification rates per 100,000 for chronic cases of hepatitis B by age and sex, 2004-2016

Notification rates per 100,000 for chronic cases of hepatitis B by age and sex, 2016

Most likely risk factor for acute cases, 2004-2016 (data available for 61%, n=424) Approximately one fifth of acute cases were born in an endemic country or were asylum seekers

Most likely risk factor for chronic cases, 2004-2016 (data available for 49%, n=3570) Born in endemic country/asylum seeker is used as a proxy for risk factor when no other risk factor has been identified. A significant proportion of the cases with risk factor data were also born in endemic countries – 89% of all chronic cases with information on country of birth or asylum seeker status were born in endemic countries or were asylum seekers.

Region of birth, 2004-2016 Acute cases with region of birth data (80%, n=556) Chronic cases with region of birth data (43%, n=3123)

Hepatitis B notifications (acute & chronic) and CSO immigration numbers from EU16-28 & non EU/EEA countries (excl North America & Australia), 2004-2016 EU 16-28 countries: Bulgaria, Croatia, Czech Republic, Estonia, Hungary, Latvia, Lithuania, Malta, Poland, Romania, Slovakia, Slovenia, Cyprus

Summary of acute hepatitis B in Ireland, 2004-2016 9% of cases notified 2004-2016 were acute infections 695 acute HBV notifications in this time period (annual average: n= 53) 32 acute cases of hepatitis B were notified in 2016. This was a 23% increase compared to 2015 (n=26), but was similar to other recent years 82% of acute cases notified 2004-2015 were male (M:F = 5:1) Mean ages at notification: 37 for males, 34 for females, 37 for both Median ages at notification: 34 for males, 30 for females, 33 for both Where risk factor data available, 73% of cases were sexually acquired Sexual orientation available for 95% of sexually acquired cases: 54% heterosexual, 46% men who have sex with men Where country of birth was available, 73% of acute cases were born in Ireland

Summary of chronic hepatitis B in Ireland, 2004-2016 91% of cases notified 2004-2016 were chronically infected 7289 chronic HBV notifications in this time period (annual average: n= 557) 418 chronic cases of hepatitis B were notified in 2016 55% of chronic cases notified 2004-2016 were male Mean ages at notification: 35 for males, 31 for females, 33 for all Median ages at notification: 33 for males, 29 for females, 31 for all Data indicate that most chronic cases were born and infected outside of Ireland, mostly in Central & Eastern Europe, Asia and Sub-Saharan Africa It is likely that most became infected at birth or in early childhood and have been infected for decades Trends in chronic cases mirror trends in immigration

Hepatitis B prevalence data – Ireland, Low risk populations General pop (residual sera, 2003)1: HBsAg 0.1%, anti-HBc 1.7% Oral fluid, postal (1998-9)2: anti-HBc 0.51% Blood donors (1997-2015)3: HBsAg 0.011% Antenatal, Rotunda 1998-20004: HBsAg 0.03% Irish, 4.2% non-EU, 0.35% overall Antenatal, West of Irl 2004-95: HBsAg 0.21% 1Nardone A et al. Epidemiol Infect 2009;137(7):961-9. 2O ’Connell T et al. Epidemiol Infect 2000;125(3):701-4. 3Personal communication, Dr Joan O’Riordan, IBTS 4Healy CM et al. Ir Med J 2001;94(4):111-2,4. 5O ’Connell K et al. Ir Med J 2010;103(3):91-2.

Hepatitis B prevalence data – Ireland, High risk populations Prisoners 19981: anti-HBc 8.7% (18.5% in IDU prisoners) Prisoners, 20112: HBsAg 0.3% IDU 2001-23: HBsAg 2%, anti-HBc 17% Homeless, Dublin 1999-20004: anti-HBc 9% Asylum seekers, HSE East 1999-20035: HBsAg 5% Asylum seekers, Screening in Balseskin6, 2004-2012: HBsAg 3.6% 1Allwright S et al. BMJ 2000;321(7253):78-82. 2National Advisory Committee on Drugs and Alcohol. Study on the prevalence of drug use, including intravenous drug use, and blood-borne viruses among the Irish prisoner population. 2011 3Grogan L et al. Ir J Med Sci 2005;174(2):14-20. 4Immunisation Guidelines for Ireland 2008. http://www.immunisation.ie/en/HealthcareProfessionals/ImmunisationGuidelines2008/. 5Doyle S. Thesis submitted for MFPHMI, RCPI; 2006. 6Brennan M et al. ICGP Forum. 2013