The Molecular Characterization of Hepatitis A Virus Strains Circulating during Hepatitis A Outbreaks in São Paulo, Brazil, from September 2017 to May 2019

Abstract

Outbreaks of hepatitis A may occur in countries of medium and high socioeconomic levels in which the population generally exhibits an increased susceptibility in young adults to this infection if they are not vaccinated against the hepatitis A virus (HAV). In Europe, an outbreak involved approximately 22 European countries with 4475 cases reported from 2016 to 2018; most of them were men who have sex with men (MSM). This outbreak expanded to North and South America, including Brazil, particularly in São Paulo city with 1547 reported cases from 2016 to 2019. In the present study, we characterized the HAV strains involved in the acute hepatitis A cases identified in the reference centers of São Paulo city during this outbreak. A total of 51 cases with positive anti-HAV IgM were included, 80.4% male, 68.6% of them between 20 and 40 years old and 41.7% MSM. HAV RNA was detected in 92% (47/51) of the cases. Subgenotype IA of HAV was identified and most of the strains were closely related to that isolated in outbreaks that occurred in different European countries in 2016. These results showed the epidemiological relation between these outbreaks and reinforce the need to implement vaccination against hepatitis A for the adult population, particularly for a population with a high-risk behavior.

Increase in Hepatitis A Cases Linked to Imported Strains to Rio de Janeiro, Brazil: A Cross-Sectional Study

“…However, the majority (30/35; 85.7%) of the 2017-2019 circulating strains were related to MSM outbreaks in Europe/Asia, most of which clustered with the VRD_521_2016 strain (23/35; 65.8%), followed by RIMV-HAV16-090 (6/35; 17.1%), and less frequently, V16-25801 (1/35; 2.8%). A similar proportion has been observed in a study conducted in Sâo Paulo [38] and in European HAV outbreaks, where the VRD_521_2016 strain was present in most cases [13]. Moreover, the strain VRD_521_2016 was identified in sewage samples from São Paulo during the outbreak [42].…”

“…A review published in 2018 by Jacobsen reported that travel to endemic regions is related to high rates of HAV infection [2]. A similar finding was observed by Chuffi and colleagues in a recent study conducted in São Paulo, where having traveled in the last 2 months before symptoms was related to HAV positivity [38]. It is important to highlight here that several MSM patients in our study reported trips to São Paulo, which was the epicenter for the HAV outbreak among Brazilian men [10,17,18].…”

“…Studies have reported sexual practices as significant risk factors for HAV infection, with the practices of oral, oroanal, and anal sex as important transmission routes [32][33][34][35]37]. Likewise, recent Brazilian studies suggested that the increased HAV incidence in Brazil could be associated with sexual practices between men [10,38]. It is noteworthy that the majority of HAV cases during the outbreak period occurred in sexually active men.…”

Temporal trends of Acute Hepatitis A in Brazil and its regions

“…The increase in HAV incidence observed after 2016 ,mainly in males between 20 and 40 years (Table 3), resembles the epidemiologic pattern found in Europe, world region with low endemicity, where most cases occurred in MSM (6-8). Although the data available for this study alone do not allow to evaluate this hypothesis, results published by others relating Hepatitis A from 2016 to 2018 point in this direction (19,20).…”

Hepatitis A in Latin America: The current scenario

“…HAV subgenotype IA was identified, with most strains closely related to those isolated during outbreaks in the same demographic group across various European countries in 2016. 16,17 A cross-sectional study conducted in Rio de Janeiro state revealed a notable increase in HAV incidence, rising from 0.3 cases per 100,000 inhabitants in 2016 to 9.0 cases in 2018 Among those affected, individuals aged 20-29 years constituted the majority (46.15%), with males comprising a significant proportion (78.85%), and a substantial portion of this demographic being MSM (57.69%). 18 Phylogenetic analysis of HAV strains revealed that all samples belonged to HAV subgenotype IA, consistent with the most prevalent genotype previously reported in Brazil.…”