Initial evaluation of universal immunization with a single dose against hepatitis A virus in Central Brazil

• Published in: The Brazilian journal of infectious diseases 2018-05, Vol.22 (3), p.166-170
• Main Authors: Brito, Wagner Izidoro de, Alves-Junior, Eduardo Rodrigues, Oliveira, Rode Martinho de, Souto, Francisco José Dutra
• Format: Article
• Language: English
• Subjects: Anti-HAV; Brazil - epidemiology; Child; Dried Blood Spot Testing; Female; Hepatitis A - epidemiology; Hepatitis A - prevention & control; Hepatitis A Antibodies - blood; Hepatitis A vaccine; Hepatitis A Vaccines - administration & dosage; Hepatitis A Vaccines - immunology; Hepatitis A Virus, Human - immunology; Humans; Immunization programs; Immunization Schedule; Immunoenzyme Techniques; INFECTIOUS DISEASES; Logistic Models; Male; Mass Vaccination - methods; Original; Program Evaluation; Retrospective Studies; Seroepidemiologic Studies; Single-dose schedule
• ISSN: 1413-8670; 1678-4391; 1678-4391
• DOI: 10.1016/j.bjid.2018.04.001

Vaccination against the hepatitis A virus (HAV) administered in two doses has been used effectively in universal child immunization programs in several countries. A single-dose vaccination was adopted in some low-income countries in an attempt to reduce costs without losing effectiveness. In 2014, single-dose universal vaccination was introduced in Brazil for children aged two years. Since such strategy is still not universally accepted, its efficacy should be compared to the two-dose strategy. To assess the humoral response after the single-dose HAV vaccination schedule, a cross-sectional study was conducted in Primavera do Leste, in Mato Grosso state, Central Brazil, including 265 children vaccinated through the National Immunization Program. Blood was collected by using a digital puncture and further applied to filter paper cards. Anti-HAV was detected in 218 out of 265 dried blood spots (DBS). Blood venous samples were collected from 34 out of 47 children who were not anti-HAV positive in DBS samples. Eighteen of them tested positive for anti-HAV, giving a final score of 93.6% (236/252) of seropositivity. In conclusion, this study demonstrated a high rate of anti-HAV positivity in the short term after single-dose hepatitis A vaccination in the population investigated. Moreover, the DBS was shown to be a reliable tool for detecting anti-HAV antibodies.