Introduction: hepatitis A virus (HAV) infection is a common cause of acute hepatitis worldwide. Since the generalization of vaccination, its incidence had markedly declined. Nevertheless, several HAV-outbreaks have been described in the last decade, mainly related to contaminated alimentary products. In recent years, a new pattern of acute HAV infection has been described with changes in the demographic profile of the infected population, which is more common in healthy young men.
Patients and methods: a retrospective case series study was performed to evaluate this possible change in the pattern of HAV infection. The case series included all patients with a diagnosis of HAV acute infection in our hospital between January 2005 and May 2017.
Results: a total of 196 cases were diagnosed which were comprised of two probable outbreaks: one starting in November 2008 of 26 cases and one starting in 2016 with 69 cases at the time of data collection. The two outbreak populations were comparable. While the sporadic cases group was predominantly formed by pediatric and third-age patients with a slight male tendency, the outbreak related cases showed a clear predominance for young males (proportion of males: 63.2% vs 85.3%, p < 0.001). A possible chronological relationship with the national gay festivity celebrated in Madrid was observed. Outbreak related cases had higher bilirubin, alanine aminotransferase and longer APPT at diagnosis as well as a lower albumin concentration. The clinical relevance was minimal with a similar hospitalization rate and clinical outcome in both groups. There were no related deaths, acute liver failure or need for liver transplantation in our cohort.
Conclusion: these epidemiological findings emphasize the importance of implementing preventive measures as well as social awareness campaigns.