Incidence of Hepatitis A in Argentina after vaccination

Abstract

Summary. In Argentina, the annual incidence rate of reported hepatitis A disease ranged from 70.5 to 173.8 per 100 000 during 1995–2004. A single dose universal hepatitis A immunization program aimed at children aged 12 months was started in June 2005. The aim was to observe the impact of universal vaccination against hepatitis A in Argentina. A longitudinal analysis of hepatitis A rates reported in Argentina since 1995 to the National Notifiable Diseases Surveillance System (SINAVE). Incidence rates in 2007 were compared with those for the prevaccination baseline period (1998–2002), overall and by age group and geographical regions. Overall vaccine coverage in Argentina was 95% in 2006 for the single dose. After initiating the program, a sharp decrease in disease rates was observed. The annual incidence of 10.2 per 100 000 during 2007 represents 88.0% reduction with respect to the average incidence rate for the period 1998–2002 (P < 0.001). For children aged 1 year, an 83.1% reduction in disease was observed in 2007, compared with the baseline period (P < 0.001). Furthermore, a sharp decline was also observed in all other age groups 87.1% [2–4 years], 88.7% [5–9 years], 83.6% [10–14 years], 78.8% [15–49 years], 20.7% [>50 years]. Also important reductions were observed in all Argentinian regions. Following the implementation of universal hepatitis vaccination with a single dose to children at 12 months of age, hepatitis A rates have declined substantially in Argentina. Monitoring is needed to verify that vaccination continues to proceed and that low rates are sustained.