Hepatitis A Outbreak in Men Who Have Sex with Men Using Pre-Exposure Prophylaxis and People Living with HIV in Croatia, January to October 2022

Hepatitis A virus subtype IB outbreak among MSM in Hungary with a link to a frozen berry source

Men who have sex with men (MSM) are at high risk of acquiring hepatitis A virus (HAV) and in recent years several HAV outbreaks mostly affecting MSM have been described. These outbreaks were caused by subtype IA strains circulating in this high-risk population. After years of low incidence, an outbreak among MSM in Hungary caused a significant increase in reported HAV infections in 2022. Samples from 224 HAV IgM-positive patients diagnosed in 2022 were tested for HAV RNA and positive samples were genotyped by sequencing. In 171 patients a unique subtype IB virus was detected with 99.8-100% sequence identity in the VP1/P2A junction. It was distinct from previously published strains, but most closely related to an Egyptian isolate. Sequence analysis revealed one dominant and three minor variants based on VP1/P2A. Whole genome sequencing revealed limited variation among these variants, suggesting a recent common origin. Epidemiological data indicated that sexual transmission was driving the outbreak for most of the year, suggested by the high male to female ratio and the large number of coinfections with HIV and other sexually transmitted infections among the patients. The outbreak was also associated with a restaurant cluster, in which one of the variants was detected and frozen berries were implicated as the source of infections. The outbreak strain was also detected in other countries around Europe and remained frequently detectable in Hungary in 2023. This study provides insights into the molecular and epidemiological characteristics of the described HAV outbreak. The results show that sequencing is not only useful in connecting cases to an outbreak, but also helps to clarify the relatedness of detected variants. Prevention strategies focusing on vulnerable communities may reduce the burden of HAV infections in the future.

Mpox across countries from Central and Eastern Europe - 2022 outbreak

BACKGROUND

The aim of the study was to assess socio-demographical characteristics, clinical presentation, and outcomes in patients diagnosed with mpox.

METHODS

A survey on patients diagnosed with mpox was performed in 14 countries from Central and Eastern Europe. Data was compared according to HIV status and country of origin (EU vs. non-EU). Mpox diagnosis was confirmed by RT-PCR from oropharyngeal swabs, skin lesions, and other body fluids.

RESULTS

Out of 154 patients confirmed with mpox in 2022, 99.3% were males, with a median age (years) of 35 (IQR 30-39), 90.2% MSM and 48.7% PLWH. Compared to HIV-negative subjects, PLWH had more frequent high-risk behaviours:chemsex (p = 0.015), group sex (p = 0.027), and a history of sexually transmitted infections (STIs) (p = 0.004). Persons from EU were more often PLWH (p = 0.042), MSM (p < 0.0001), had multiple sexual partners (p = 0.025), practiced chemsex (p = 0.008) or group-sex (p = 0.005) and had more often history of STIs (p < 0.0001). The median CD4 cell count/mL at mpox diagnosis was 713 (IQR 486-996) and 73.5% had undetectable HIV VL. The commonest clinical features were fever (108 cases), lymphadenopathy (78), and vesiculo-pustular rash: penile (76), perianal (48), limbs (67). Fifty-one (31%) persons were hospitalized due to complications or epidemiological reasons. Three patients received tecovirimat or cidofovir. The outcome was favorable for all patients, including 4 with severe forms.

CONCLUSIONS

Mpox was diagnosed predominantly in young MSM, with high-risk behaviors and history of STIs. Effective contact tracing and vaccination are important strategic pillars to control mpox outbreaks.

A Randomized Clinical Trial of 1-Dose vs Accelerated 2-Dose Schedule for Hepatitis A Virus (HAV) Revaccination Among People With Human Immunodeficiency Virus Who Were Nonresponders or Had Seroreversion After Primary HAV Vaccination

BACKGROUND

For people with human immunodeficiency virus (PWH) who have no serological responses to their primary hepatitis A virus (HAV) vaccination or have seroreversion after successful primary vaccination, the optimal revaccination strategy remains unclear.

METHODS

In this open-label, randomized clinical trial, PWH who tested negative for anti-HAV antibodies after receiving a standard 2-dose series of primary HAV vaccination were enrolled and assigned in a 1:1 ratio to receive either 1 dose (the 1-dose group) or 2 doses of HAV vaccine administered 4 weeks apart (the 2-dose group). Serological response rates and anti-HAV antibody titers were compared at weeks 24 and 48.

RESULTS

Of the 153 participants (77 in the 1-dose group and 76 in the 2-dose group), the overall serological response rates at week 48 after revaccination were similar between the 2 groups (2- vs 1-dose, 80.2% vs 71.4%, P = .20). However, anti-HAV antibody titers were consistently higher in the 2-dose group than in the 1-dose group. In subgroup analysis, PWH who were nonresponders to primary HAV vaccination were significantly more likely to mount a serological response after 2-dose HAV revaccination (68.4% vs 44.1%, P = .038). No severe adverse events were reported throughout the study.

CONCLUSIONS

Two-dose HAV revaccination administered 4 weeks apart yielded similar serological responses as 1-dose revaccination among PWH who were nonresponders or had seroreversion after primary HAV vaccination. The 2-dose revaccination schedule generated significantly higher anti-HAV antibody titers and was more likely to elicit serological responses at week 48 among PWH who were nonresponders to primary HAV vaccination. Clinical Trials Registration. NCT03855176.

Seroprevalence Trends and Molecular Epidemiology of Viral Hepatitis in Croatia

Viral hepatitis is a significant cause of morbidity and mortality worldwide. In Croatia, hepatitis B virus (HBV) and hepatitis C virus (HCV) are widely distributed, especially in some high-risk groups such as people who inject drugs (PWID), prisoners, and highly promiscuous groups. The seroprevalence of HBV ranges from 7.0% in the general population to 38.8% in PWID, depending on the region. The seroprevalence of HCV is highest among PWID (29-75.5%) as compared to 0.9% in the general population. Analyzing the distribution of HCV genotypes, no substantial changes in the molecular epidemiology of the two most frequent HCV genotypes (1 and 3) in the past 20 years were observed. However, the predominance of subtype 1b compared to subtype 1a as detected in 1996-2005 was not confirmed in 2008-2015. Hepatitis A virus (HAV) incidence was high in the past with a decreasing trend since the 2000s, except for an outbreak in 2017-2018 as part of the large European outbreak, which was mainly among men who have sex with men. Hepatitis E virus (HEV) is an emerging virus detected for the first time in Croatia in 2012. The seroprevalence of HEV is high among hemodialysis patients (27.9%) and liver transplant recipients (19.3-24.4%). In addition, higher seroprevalence rates were observed in animal-related professions (e.g., veterinarians, 15.2%; hunters, 14.9%). All detected HEV strains belonged to genotype 3.