Data
Surveillance based on data from the National Reference Center and its expertise, combined with various studies conducted over time, has provided a better understanding of the epidemiology of hepatitis E in France.
A Significant Increase in Hepatitis E Testing in France
Between 2011 and 2016, the number of patients tested increased 22-fold. The reasons for this increase are likely linked to improved coverage of the NRC network since its relocation and greater use of diagnostic tests now available on the market.
This increase in the number of tests performed was accompanied by an increase in the number of positive cases, indicating that the disease was underestimated in France prior to 2012.
An indigenous disease
While hepatitis E was long considered an imported disease, advances in diagnostics and expanded surveillance network coverage have demonstrated that hepatitis E is indeed an indigenous disease in France, with over 99.5% of cases acquired within mainland France. The situation is similar in most European countries.
Indeed, between 2002 and 2016, the number of imported cases remained stable over time, while the number of indigenous cases has been steadily increasing. Table 1 distinguishes imported cases of acute hepatitis E (stay in an endemic area within 3 months prior to diagnosis) from indigenous cases or those with an unspecified epidemiological context.
| Year | Year | Number of cases (n) | Positive (n/N) (%) | ||
|---|---|---|---|---|---|
| imported | Domestic | Total | |||
| 2002 | 209 | 4 | 9 | 13 | 6 |
| 2003 | 155 | 11 | 3 | 14 | 9 |
| 2004 | 233 | 4 | 16 | 20 | 8 |
| 2005 | 327 | 19 | 20 | 39 | 12 |
| 2006 | 583 | 14 | 24 | 38 | 6 |
| 2007 | 1,012 | 10 | 97 | 107 | 10 |
| 2008 | 1,700 | 21 | 159 | 180 | 10 |
| 2009 | 2,150 | 23 | 183 | 206 | 10 |
| 2010 | 2,549 | 16 | 216 | 232 | 9 |
| 2011 | 3,429 | 19 | 249 | 266 | 8 |
| 2012 | 17,566 | 9 | 801 | 810 | 5 |
| 2013 | 35,416 | 3 | 1,848 | 1,851 | 5 |
| 2014 | 44,382 | 12 | 1,813 | 1,825 | 4 |
| 2015 | 66,000 | 4 | 2,118 | 2,122 | 3 |
| 2016 | 76,000 | 10 | 2,292 | 2,302 | 3 |
| 2017 | 80,000 | 26 | 2,219 | 2,245 | 3 |
Demographic Data
Most cases of hepatitis E among Indigenous people are men, with an average age of over 55. Diagnosed cases are found in all metropolitan areas, with a concentration in the South.
| Year | Male-to-female ratio | Average age | Southern Regions* | |
|---|---|---|---|---|
| Year | [range] | |||
| 2002–2004 | 3 | 45 | [4–78] | 70% |
| 2006 | 1.8 | 45.5 | [23–64] | 65% |
| 2007 | 2.7 | 56 | [30–69] | 72% |
| 2008 | 2.7 | 56 | [9–83] | 60% |
| 2009 | 4.6 | 61 | N/A | 57% |
| 2010 | 2.9 | 55 | [9–83] | 50% |
| 2011 | 2.6 | 55 | N/A | N/A |
| 2012 | 2.5 | 55 | N/A | 40% |
| 2013 | 2.1 | 54 | N/A | 46% |
| 2014 | 1.9 | 55±15 | N/A | 45% |
| 2015 | 2.1 | 54±15 | N/A | 37% |
| 2016 | 1.8 | 54±15 | N/A | 48% |
| 2017 | 1.5 | 55±20 | N/A | N/A |
* Aquitaine, Midi-Pyrénées, Languedoc-Roussillon, Provence-Alpes-Côte d’Azur, Corsica: region of residence of the patient or the collecting laboratory
Source: CNR Hepatitis E
These CNR data on distribution by sex and age are supported by seroprevalence studies conducted over time.
Virological data:
Since 2007, the vast majority (>90%) of strains from locally acquired cases have been genotype 3. Genotypes 1, 2, and 4 were strains from imported cases, except for genotype 4 starting in 2011 (locally acquired cases).
Among the various subtypes of genotype 3, subtype 3f has been predominant since 2007 (>60%), followed by subtypes 3chi (9% to 35%). In 2013, an increase in the number of subtype 3chi cases was observed, and this remained stable in subsequent years.
During the 2012–2016 period, a shift in genotype distribution was observed: a decrease in the proportion of genotype 3f and a concomitant increase in cases of infection with genotype 3chi.
Seroprevalence data:
Estimates of anti-HEV seroprevalence vary from one study to another and depend on the sensitivity of the test used and the study population. The most recent studies using a highly sensitive test report higher prevalence estimates, for example among blood donors in the Midi-Pyrénées region (2003–2004 vs. 2010)
Data on risk factors for hepatitis E and possible sources of infection
Investigations into several clusters of cases between 2010 and 2015 identified or suggested various sources of contamination
