High prevalence of hepatitis A and E viruses in environmental and clinical samples from West Argentina.

Environmental surveillance of water sources is important to monitoring viral hepatitis transmission in clinical settings. This study investigated the circulation of hepatitis A (HAV) and E (HEV) viruses in sewage and clinical samples from Argentina. Between 2016 and 2017, 80 raw sewage samples and 86 clinical samples (stool and serum) from suspected cases of hepatitis A and hepatitis E were obtained. HAV and HEV were tested by both real-time and nested PCR. Positive samples were sequenced for genotype determination and phylogenetic analysis. Overall, HAV was recovered in 39% of sewage samples and 61.1% of clinical samples. HEV was detected in 22.5% of sewage samples and 15.9% of clinical samples. HAV was found more frequently in sewage during the winter and in clinical samples in spring; HEV was more prevalent in sewage during summer and in clinical samples in autumn. All HAV isolates belonged to genotype IA and HEV isolates belonged to genotype 3, the most prevalent genotypes in South America. High prevalence of HAV and HEV in environmental and clinical samples in Mendoza, Argentina was observed. These findings reinforce the importance of environmental surveillance and implementation of health strategies to control the spread of HAV and HEV in developing countries.

Epidemiology of hepatitis B and C virus infection in Central West Argentina.

Little information is available regarding the prevalence of viral hepatitis in Central West Argentina. This study aims to give new information regarding HBV and HCV prevalence, genotypes, and risk factors in Central West Argentina and the suitability of dried blood spot (DBS) sampling for HBV and HCV screening. METHODS: A total of 622 individuals were included; the mean age was 36.6 ± 14.3 years and 55.4% were females. HBV and HCV markers were detected using serological and molecular analysis, and risk factors were evaluated using statistical analysis. RESULTS: Using serum samples, the HBsAg prevalence was 1.8%, the rate of HBV exposure (anti-HBc positivity) was 5.3%, and the rate of HBV immunity was 34.9%. HBV DNA was found in four out of 11 HBsAg+ samples, and the viruses in three of these samples were classified as genotypes A1, A2 and F2a. Multivariate analysis showed that anti-HBs positivity was associated with the level of schooling and history of HBV vaccination. The anti-HCV prevalence was 2.6%, and HCV RNA was found in 11 samples, seven of which contained viruses of genotypes 1a (n = 2), 1b (n = 3) and 2 (n = 2). The sensitivity of the DBS assay for HBsAg, anti-HBc, and anti-HCV was 100%, 66.6%, and 75%, respectively, and the specificity was above 98% for all markers when compared to serum. CONCLUSION: A low rate of HBV immunity was observed, demonstrating the importance of HBV vaccination. High HCV prevalence was found, and HCV 1b was closely related to other Argentinian isolates. Finally, the performance of DBS testing in this population needs more optimization to increase its sensitivity and specificity.

Seven-year follow-up of the immune response after one or 2 doses of inactivated hepatitis A vaccine given at 1 year of age in the Mendoza Province of Argentina.

This monocenter, descriptive, prospective, non-interventional study evaluated the long-term immune responses following routine vaccination with one or 2 doses of a licensed inactivated hepatitis A (HA) vaccine (Avaxim® 80U Pediatric) at age 11-23 months in a cohort of children from Mendoza, Argentina. Antibodies to hepatitis A virus (anti-HAV) were quantified annually up to Y5, and at Y7. Children whose titer decreased to below the seroprotection threshold (defined as an anti-HAV antibody concentration of ≥ 10 mIU/mL in a microparticle enzyme immunoassay up to Y5, or ≥ 3 mIU/mL in an electrochemiluminescence immunoassay at Y7) received a routine booster dose of the same HA vaccine. This report summarizes the data at 7 year after the first vaccination. Of 546 participants initially included, 264 participants remained at Y7 and provided blood samples. Of these, 204 having received one HA primary dose as a toddler were still seroprotected at Y7; titers for a further 7 also having received one HA dose as a toddler fell to below the seroprotection threshold and they therefore received a booster; all 53 having received 2 HA doses as a toddler and still present at Y7 remained seroprotected at Y7. One or 2 primary doses of this HA vaccine in toddlers result in very good persistence of anti-HAV up to 7 year post-first vaccination.