Beyond Foodborne HAV: Sexual Transmission Drives a New Wave of Cases in Romania.

Background: In 2022, Romania experienced a sharp increase in hepatitis A virus (HAV) infections, with evidence of predominant fecal-oral transmission through sexual contact, raising concern for an outbreak among men who have sex with men (MSM). Methods: We conducted a prospective multicenter study between 1 March 2022 and 1 March 2023 in two tertiary hospitals in Bucharest. HAV infection was defined by a compatible clinical presentation, elevated liver enzymes, and positive anti-HAV IgM serology. Clinical and laboratory characteristics were compared by transmission route and HIV status. Results: A total of 191 patients were diagnosed with HAV, including 105 MSM and 86 with foodborne transmission. All were unvaccinated. Most patients were male (82.2%), with a median age of 30 years (IQR 24-38). MSM were significantly younger and reported higher-risk sexual behaviors, including chemsex and multiple or occasional partners (p < 0.0001). Among MSM, 48 (25.1%) were living with HIV, most with preserved immune status and undetectable viral loads. Clinical manifestations were similar across groups, with jaundice being most frequent (89.5%). However, MSM exhibited more severe hepatocellular injury, reflected by higher ASAT and ALAT levels and lower prothrombin concentration, independent of HIV status. MSM were also more likely to have concomitant sexually transmitted infections, including syphilis and mpox (p < 0.001). Disease was predominantly mild, although MSM had longer hospital stays. Conclusions: The 2022 HAV surge in Romania was driven by both sexual and foodborne transmission. Targeted HAV vaccination, along with integrated sexual health services and harm-reduction strategies, is essential to prevent future outbreaks.