In 2004 the average person walking into a harm reduction service in France was 35 years old. In 2023 the average was 44. Over twenty years the population aged, and injecting stayed. In 2023, 61.7 per cent injected, a share the authors describe as stable. Over the same period the hepatitis C virus lost ground.
The work appeared in Nature Communications on 11 October 2026. The first author is Chiara E. Sabbatini of Santé publique France, the French national public health agency. The last is Marie Jauffret-Roustide of Inserm, at the Centre d'étude des mouvements sociaux in Paris. The data come from the ANRS-Coquelicot survey. The journal has released the accepted version early. For now the abstract, declarations and acknowledgements can be read. The full text, with participant numbers per year and the cities involved, is not yet out, and this piece is based on the abstract.

There are three surveys, in 2004, 2013 and 2023. Each time, people who use drugs were recruited at harm reduction services, the centres that hand out sterile syringes, offer testing and steer people to care without requiring them to stop. Each participant answered questions on behaviour and gave a biological sample. The authors looked for two things. Antibodies against the virus, which persist after recovery and mark past contact. And viral RNA, the virus's genetic material, which is found in the blood only while infection is ongoing.
The key figure concerns RNA. Among all people who use drugs, the share with active virus fell from 19.4 per cent in 2013 to 9.5 per cent in 2023. The 95 per cent confidence intervals run from 16.3 to 23.0 and from 7.2 to 12.3, and do not overlap. Among people who inject, the share went from 29.6 to 14.5 per cent.
The second figure is incidence, the rate at which new infections appear. It is measured in person-years. One hundred person-years are, for instance, a hundred people followed for a year. Among people who inject, new infections fell from 6.5 to 2.4 per 100 person-years. The intervals are wide, 4.1 to 8.0 and 1.4 to 4.2, and they touch at the edges. Incidence was not counted directly. It was estimated with two-state transmission models, infected and uninfected, from prevalence by age and period.

The authors attribute the decline, most likely, to two things together. One is the roll-out of direct-acting antivirals, tablets that block viral replication and have transformed hepatitis C treatment over the past decade. The other is harm reduction policy. The reading is plausible, but it rests on three snapshots taken years apart. The abstract does not say how many people were treated, or whether those recruited in 2023 resemble those of 2013 in place and habits. The ageing of the group itself changes the picture, because someone with a decades-old infection has had more chances to be treated.
The authors also write that transmission continues. An incidence of 2.4 per 100 person-years still means new infections every year, in a group where six in ten inject.
The study is funded by French public bodies, the ANRS agency for AIDS and hepatitis research, the Ministry of Health, Santé publique France, Inserm and the regional health agencies. The authors declare no competing interests.

Italy offers a point of comparison. A Ministry of Health decree of 14 May 2021 defined the groups for free hepatitis C screening, people born between 1969 and 1989, people followed by the SerD (Servizi per le Dipendenze, the public addiction services) and prisoners of any age. Umbria's regional plan, for example, set it as a one-off pilot for 2022 and 2023. Repeated surveys like the French ones are how a country learns whether screening and treatment actually reach people who inject.
The full text should give the number recruited, the cities, and the number who received antivirals. Until then two figures stand. Active virus halved in ten years, and an average age up by nine.

References
Sabbatini Chiara E., Le Strat Yann, Bonaldi Christophe, Brouard Cécile, Audran Martin, Saboni Leïla, Richard Jean-Baptiste, David Amélie, Gaudy-Graffin Catherine, Chevaliez Stéphane, Barin Francis, Stefic Karl, Jauffret-Roustide Marie, "HCV incidence and prevalence trends among people who use drugs in France 2004 to 2023", Nature Communications, 2026, online 11 October 2026 (received 25 July 2025, accepted 22 September 2026), accepted version released early, volume and article number not yet assigned, open access, CC BY 4.0 licence. doi: 10.1038/s41467-026-78598-3
Regione Umbria (Umbria Region), "Piano regionale di screening per l'eliminazione del virus HCV", annex 1 to regional resolution DGR no. 1370 of 2021, citing the Italian Ministry of Health decree of 14 May 2021 for the target groups. https://prevenzione.regione.umbria.it/wp-content/uploads/2024/12/DGR_1370_2021_ALL-1-Piano-regionale-screening-HCV.pdf

*Board Member, SRSN (Roman Society of Natural Science)
Past Editor-in-Chief Italian Journal of Dermosurgery