1240. Hepatitis A in Latin America and the Caribbean: a Systematic Literature Review on Endemicity Patterns and Immunization Programs
Authors: Parellada Cintia I , Prieto Emilia , Carias Cristina , Valderrama Martha Carolina , Samacá-Samacá Daniel , Hernandez Fabian , Monsanto Homero 
Published: December 2022

Abstract

Background
In 2019, hepatitis A virus (HAV) infections caused around 39,600 deaths worldwide. Age-specific seroprevalence is used as a marker to classify endemicity. In countries with intermediate endemicity, WHO recommends universal HAV vaccination for children ≥1 year considering local disease burden and cost-effectiveness analyses. This review aimed to describe the endemicity patterns and HAV immunization programs in Latin America and the Caribbean (LAC).

Methods
We conducted a systematic literature review using MEDLINE, Embase, CENTRAL, CDRS, Lilacs, and Scopus from January 2005 to December 2021. Additionally, we searched grey literature, including Pan American Health Organization/WHO country profiles and official government websites in January 2022. The main outcomes were HAV seroprevalence and characteristics of HAV immunization programs.

Results
We identified 30 studies containing data on HAV seroprevalence in LAC and 13 records from grey literature on HAV vaccination program. As of January 2022, among 33 countries, 8 had public universal childhood HAV vaccination program and 12 had programs for at least one population at-risk (Figure 1 and Table 1). Only 7 countries had seroprevalence data available (Figure 2). Using WHO criteria, 5 countries were classified as intermediate endemicity; 2 have already introduced HAV vaccination in the NIP (Brazil and Colombia) and 3 have not introduced yet (Bolivia, Mexico, and Peru). In Argentina and Brazil, studies conducted in certain populations at risk, such as men who have sex with men and healthcare workers aged between 20-40 years, showed higher susceptibility to infection (seroprevalence: 40%-60%). Figure 1.Hepatitis A routine immunization schedule in national immunization programs in Latin America and the Caribbean, 2022
a Available for Guatemalan Social Security Institute (employed people in formal sector), which represents 17% of total population. b Countries that included in national immunization program for at least one population at risk Table 1.Characteristics of hepatitis A immunization programs in Latin America and the Caribbeana Populations at risk: 2-dose schedule; b Partial introduction in 2014 in endemic areas; c only available for Guatemalan Social Security Institute (formally employed population), which represents 17% of total populationFigure 2.Hepatitis A endemicity level in studies conducted in Latin America and the Caribbean based on WHO classification criteriaa general population; b premarital exam; c health care workers; d children school; e liver cirrhosis; f national survey; g samples from labs, h beauticians; i population-based survey; j chronic HCV infection; k rural settlement; l low socioeconomic groups; m chronic HCV infection; n men who have sex with men/ transgender women. Mantovani 2015 and Pereira 2016 are included in the review and not showed here (description of prevalence &lt; 5 y)

Conclusion
Eight countries had universal HAV vaccination program and 12 offered for at least one population at-risk. LAC countries where HAV seroprevalence was available showed predominance of intermediate endemicity. Bolivia, Mexico, and Peru would benefit from universal childhood vaccination, and Argentina and Brazil should evaluate increasing susceptibility among adults at-risk to expand access to vaccination. In countries without recent data, surveillance of acute cases/outbreaks and seroprevalence studies are needed to guide the HAV vaccination implementation.

Disclosures
Cintia I. Parellada, MD, PhD, MSD Brazil: Employee of MSD Brazil, a subsidiary of Merck & Co., Inc.,|MSD Brazil: Stocks/Bonds Emilia Prieto, MD, MSc, MSD Colombia: Employee of MSD Colombia, a subsidiary of Merck & Co., Inc.,|MSD Colombia: Stocks/Bonds Cristina Carias, PhD, Merck & Co., Inc.: Employee|Merck & Co., Inc.: Stocks/Bonds Martha Carolina Valderrama, MD, Msc, IQVIA: Advisor/Consultant|IQVIA: Employee of IQVIA who received funding to execute this study Daniel Samacá-Samacá, Msc, IQVIA: Advisor/Consultant|IQVIA: Employee of IQVIA who received funding to execute this study Fabian Hernandez, BSPharm, Msc, IQVIA: Employee of IQVIA who received funding to execute this study Homero Monsanto, PhD, Merck & Co., Inc.: Employee.