Particularities of the Post-Pandemic Hepatitis A Outbreak in a Tertiary Infectious Diseases Hospital in Romania

<b>Background/Objectives:</b> In addition to classical transmission routes, hepatitis A (HA) outbreaks were, for the first time, linked to sexual activity in the late 1970s, particularly among men who have sex with men (MSM). Since then, outbreaks have continued to emerge globally among adults engaging in high-risk sexual behaviors, reinforcing the ongoing public health significance of this transmission route. Although the COVID-19 pandemic temporarily reduced HA cases, outbreaks reemerged following the relaxation of pandemic measures. This study aims to report the HA outbreak registered at Romania's tertiary infectious diseases hospital during the first half of 2022. <b>Methods:</b> We retrospectively analyzed all HA cases admitted to the National Institute for Infectious Diseases from 1 January to 1 August 2022. <b>Results:</b> Among 51 cases, eight children (under 14) were excluded from further analyses. Of the 43 remaining cases, 37 (86%) were male, with 20/37 (54.05%) identified as MSM. Twenty-two of the males (59.45%) were previously or concomitantly diagnosed with sexually transmitted diseases (STDs), notably syphilis and HIV. A marginal finding: 14 out of 29 patients screened for hepatitis E tested positive for IgM. The MSM patients exhibited significantly higher transaminase levels (ALT median level 3404 U/L [IQR 2608-5448] vs. 2066 U/L [IQR 1393-3682]) and more severe liver impairment (INR median level 1.37 [IQR 1.18-1.78] vs. 1.18 [IQR 1.11-1.43] compared to non-MSM patients. While direct bilirubin levels were higher in MSM (7.4 mg/dL vs. 5.5 mg/dL), the difference was not statistically significant. <b>Conclusions:</b> An HA outbreak occurred at the beginning of 2022 among Romanian young MSM, with a more severe acute liver injury. High-risk sexual practices may be a potential risk factor for severe HA. This emphasizes the need to screen for STDs in young males with HA and review vaccination policies for at-risk individuals.