Incidence of Hepatitis A in Argentina after vaccination

Abstract

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.