In 2018, 1,525 cases of acute hepatitis A were reported, including 1,442 in mainland France. The annual case rate for acute hepatitis A across all of France was 2.3 per 100,000 inhabitants (Figure 1). This decrease compared to 2017 (5.1 per 100,000 inhabitants) is linked to the end of the epidemic that began in late 2016 and particularly affected men who have sex with men (MSM).

Due to the end of the epidemic, disparities in reported rates between men (2.8 per 100,000) and women (1.8 per 100,000) narrowed in 2018. The sex ratio was 1.4 (average of 1.3 between 2006 and 2016), with a gradual decline throughout the year, falling below 1.5 starting in May 2018. In total, 42% of cases in 2018 were women (Figure 2). The average age of reported cases was 28 years (ranging from 1 to 97 years). The highest incidence this year was again found among those aged 6 to 15, as in the years prior to 2017. The proportion of cases aged 26 to 45, which was the highest in 2017 (46%), decreased in 2018 to 29% of all reported acute hepatitis A cases (Figure 3).

For more than three-quarters of cases reported in 2018, jaundice was reported, and 50% were hospitalized.

Geographically, the highest reporting rate was 19.2 per 100,000 in the overseas department of Mayotte; elsewhere, reporting rates ranged from 5.5 per 100,000 inhabitants (Indre) to 0 in the departments of Ardennes and Haute-Loire, where no cases were reported in 2018. Only two departments had a reported rate of 5 per 100,000 or higher in 2018 (compared to 27 departments in 2017) (Map).

The main risk exposures in the 2 to 6 weeks prior to the onset of symptoms were travel outside mainland France (43% of cases), followed by exposure to hepatitis A cases in the immediate environment (31% of cases), of which 73% were within the family, and consumption of seafood (26% of cases) (Figures 4 and 5). Among cases who had traveled outside mainland France, the distribution of countries visited also differed from previous years, with 56% of cases having traveled to a Maghreb country (29% in 2017) and 12% having traveled to a European country (41% in 2017). In 2018, an increase in the number of cases upon return from Morocco was noted as early as April, with the circulation of a strain of HAV also found in travelers to Morocco originating from other European countries. These events were likely linked to an ongoing outbreak in Morocco.

Data on sexual practices are not collected as part of the mandatory reporting of acute hepatitis A cases. During the 2017 outbreak, a body of evidence indicated that the majority of those affected were MSM: the significant shift in the sex ratio (Figure 2), investigations of clustered cases involving MSM, strain sequencing, and the observation of similar phenomena in various European countries. During 2018, the gradual decrease in the sex ratio allowed the epidemic to be declared over as of May 2018. Sequencing of the strains by the CNR (virology laboratory at Paul Brousse University Hospital) confirmed the decline in the circulation of the 2017 epidemic strains.

The epidemiology of acute hepatitis A in France in 2018 continues to justify the application of vaccination recommendations advocating vaccination of MSM, as well as for family members of a confirmed case and during travel to an endemic area (2019 Vaccination Schedule and Health Recommendations for Travelers, 2019).

Characteristics and Risk Factors of Reported Cases of Acute Hepatitis A by Age Group, France, 2018

¹ Percentages calculated for reported cases, ² asthenia, anorexia, fever, vomiting, abdominal pain, diarrhea