Mpox outbreak in France: epidemiological characteristics and sexual behaviour of cases aged 15 years or older, 2022.

BackgroundLocally-acquired mpox cases were rarely reported outside Africa until May 2022, when locally-acquired-mpox cases occurred in various European countries.AimWe describe the mpox epidemic in France, including demographic and behavioural changes among a subset of cases, during its course.MethodsData were retrieved from the enhanced national surveillance system until 30 September 2022. Laboratory-confirmed cases tested positive for monkeypox virus or orthopoxviruses by PCR; non-laboratory-confirmed cases had clinical symptoms and an epidemiological link to a laboratory-confirmed case. A subset of ≥ 15-year-old male cases, notified until 1 August, was interviewed for epidemiological, clinical and sexual behaviour information. Association of symptom-onset month with quantitative outcomes was evaluated by t- or Wilcoxon tests, and with binary outcomes, by Pearson's chi-squared or Fisher exact tests.ResultsA total of 4,856 mpox cases were notified, mostly in Île-de-France region (62%; 3,025/4,855). Cases aged ≥ 15 years were predominantly male (97%; 4,668/4,812), with 37 years (range: 15-81) as mean age. Between May and July, among the subset interviewed, mpox cases increased in regions other than Île-de-France, and mean age rose from 35 (range: 21-64) to 38 years (range: 16-75; p = 0.007). Proportions of cases attending men-who-have-sex-with-men (MSM) meeting venues declined from 60% (55/91) to 46% (164/359; p = 0.012); median number of sexual partners decreased from four (interquartile range (IQR): 1-10) to two (IQR: 1-4; p < 0.001).ConclusionChanges in cases' characteristics during the epidemic, could reflect virus spread from people who were more to less behaviourally vulnerable to mpox between May and July, or MSM reducing numbers of sexual partners as recommended.

History of smallpox vaccination and marked clinical expression of mpox among cases notified in France from May to July 2022.

OBJECTIVES: The aim was to estimate the effect of reported history of smallpox vaccination prior to 1980 on clinical expression of mpox. METHODS: We included all confirmed mpox cases identified by the national mpox surveillance system in France between May and July 2022. Cases tested positive for monkeypox virus or orthopoxviruses by PCR. Cases were interviewed by phone using a questionnaire documenting demographics, symptoms and exposures. To estimate the effect of smallpox vaccination on the presence of marked mpox symptoms (association of fever, lymphadenopathy and extensive mucocutaneous lesions), we estimated prevalence ratios (PRs) and 95% CIs using Poisson regression models with robust standard errors. RESULTS: There were 1888 confirmed mpox cases with date of symptom onset between 7 May and 31 July 2022. Overall, 7% (93/1394) presented marked mpox symptoms. Among patients who provided information about their vaccination status, 14% (207/1469) reported smallpox vaccination prior to 1980. The proportion of cases with marked symptoms was 2% (3/170) among those reporting smallpox vaccination prior to 1980 and 8% (76/974) among those who reported no vaccination. The proportion of marked symptoms was four times lower among cases reporting previous smallpox vaccination than in cases reporting no vaccination (PR, 0.24; 95% CI: 0.08-0.76). There was no evidence of an effect of smallpox vaccination on development of complications (PR, 0.65; 95% CI: 0.35-1.22) or hospitalization due to mpox (PR, 0.64; 95% CI: 0.23-1.80). DISCUSSION: Our results suggest that smallpox vaccination during childhood attenuated the clinical expression of monkeypox virus infection, but there was no evidence of an effect on complications or hospitalization.