Hepatitis A Outbreak Characteristics: A Comparison of Regions with Different Vaccination Strategies, Spain 2010–2018

Abstract

We compared the cumulative incidence and characteristics of hepatitis A outbreaks in two groups of Spanish autonomous regions according to whether a universal or risk group vaccination strategy was followed. Outbreaks between 2010 and 2018 were analyzed. The cumulative incidence rate of outbreaks was estimated and compared by estimating the rate ratio (RR). The characteristics of the outbreaks and those of the first cases were compared. Adjusted OR (aOR) were calculated using a multivariate logistic regression model. Outbreak incidence was 16.04 per million persons in regions with universal vaccination and 20.76 in those with risk-group vaccination (RR 0.77; 95%CI 0.62–0.94). Imported outbreaks accounted for 65% in regions with universal vaccination and 28.7% in regions with risk-group vaccination (aOR 3.88; 95%CI 2.13–7.09). Adolescents and young adults aged 15–44 years and men who have sex with men were less frequently the first case of the outbreak in regions with a universal vaccination strategy (aOR 0.54; 95%CI 0.32–0.92 and 0.23; 95%CI 0.07–0.82, respectively). The cumulative incidence rate of outbreaks was lower in regions with universal vaccination. In all regions, independently of the vaccination strategy, activities to vaccinate persons belonging to high-risk groups for infection should be emphasized.

Healthcare and Epidemiological Surveillance Costs of Hepatitis A Outbreaks in Spain in Regions with and without Universal Hepatitis A Vaccination of Children during 2010-2018

“…The following Spanish regions were included in the study: Catalonia, Castile and Leon, Murcia, Navarra, the Community of Madrid and the Community of Valencia. Catalonia implemented the first hepatitis A vaccination strategy [ 14 ]. Castile and Leon, Murcia, Navarra, the Community of Madrid and the Community of Valencia implemented the second hepatitis A vaccination strategy [ 14 ].…”

“…Catalonia implemented the first hepatitis A vaccination strategy [ 14 ]. Castile and Leon, Murcia, Navarra, the Community of Madrid and the Community of Valencia implemented the second hepatitis A vaccination strategy [ 14 ].…”

“…All hepatitis A outbreaks in Castile and Leon, Catalonia, the Community of Valencia, the Community of Madrid, Murcia and Navarre reported to the National Center of Epidemiology during 2010–2018 were included in the study. A hepatitis A outbreak was defined as two or more hepatitis A cases exposed to a common source of infection (epidemiological link) [ 14 ].…”

“…In Spain, hepatitis A vaccination is recommended for high-risk population groups, including patients with chronic liver disease, people traveling to countries with high rates of hepatitis A and people engaging in male-to-male sex or intravenous drug use [ 13 ]. However, since 1999, the region of Catalonia and the city of Ceuta have implemented hepatitis A vaccination programs targeting children and pre-adolescents [ 14 ]. Catalonia, an autonomous region with 8 million inhabitants, introduced the universal hepatitis A vaccination of pre-adolescents in 1999, and two doses of the hepatitis A vaccine have been administered to children aged 12–15 months and 6 years since 2014 [ 14 ].…”

“…However, since 1999, the region of Catalonia and the city of Ceuta have implemented hepatitis A vaccination programs targeting children and pre-adolescents [ 14 ]. Catalonia, an autonomous region with 8 million inhabitants, introduced the universal hepatitis A vaccination of pre-adolescents in 1999, and two doses of the hepatitis A vaccine have been administered to children aged 12–15 months and 6 years since 2014 [ 14 ]. Children aged 6 years vaccinated with only one dose of the vaccine receive the second dose at 11–12 years.…”