Monkeypox: Update on the Situation in France as of March 23, 2023

Santé publique France has released an update as of March 23, 2023, on cases of mpox (formerly known as monkeypox) following the reporting and investigation of a cluster of cases in the Centre-Val de Loire region.

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New developments since the last update on January 24, 2023

  • 17 clustered cases of mpox reported in the Centre-Val de Loire region

  • 1 additional case reported outside this cluster

  • The characteristics of the reported cases remain unchanged

This update includes cases confirmed biologically by PCR and those not confirmed by PCR. The latter include probable cases (suggestive clinical signs + high-risk contact with a confirmed case) and possible cases (suggestive clinical signs + exposure to a risk of infection).

Internationally, and due to differences in surveillance protocols across countries, biologically confirmed cases remain the benchmark for comparing epidemiological situations between countries.

Situation Update in France

In early May 2022, cases of monkeypox (mpox) with no direct link to travel in Central or West Africa—where the virus is present—or to travelers returning from those regions were reported in Europe and around the world. Since then, the disease has been subject to enhanced surveillance in France and across Europe, based on mandatory reporting, for which the form has been specifically updated.

As of March 23, 2023, at 12:00 p.m., 5,000 cases of mpox virus infection have been recorded in France, representing 18 additional cases since the January 24 report. Of these 5,000 cases, 4,144 (83%) have been biologically confirmed, and 856 (17%) are probable or possible cases that have not been biologically confirmed.

The distribution of cases by region of residence (or by region of reporting when the region of residence is unknown) is shown in Figures 1 and 2. The Île-de-France region has the highest number of cases (3,120, or 63%), followed by Auvergne-Rhône-Alpes (356 cases), Provence-Alpes-Côte d’Azur (334 cases), and Occitanie (330 cases); 27 cases reside abroad. The 18 new cases reported since the last update all involve men, and 17 of them were diagnosed in the Centre-Val de Loire region (see below).

The vast majority of adult cases reported to date are male, and 2.9% are women over the age of 15 (143 cases, including 113 biologically confirmed cases and 30 unconfirmed cases). No female cases have been diagnosed since the update on January 24, 2023.
The median age of adult cases is 36 years; 25% of cases are under 29 years old, and 25% are between 43 and 81 years old.
Twenty-four children under 15 years of age (0.5% of total cases) have been reported since May 2022 (12 biologically confirmed cases and 12 unconfirmed cases). No pediatric cases have been diagnosed since the January 24, 2023, update.
Biologically
unconfirmed cases have a profile comparable to confirmed cases: 3.7% of adults are female (vs. 2.8% of confirmed adult cases), the median age of adults is 36 years, as in confirmed cases, and the majority reside in the Île-de-France region (72% vs. 60% of confirmed cases).

Among all cases for which information is available, 101 (2.0%) were hospitalized for treatment of their mpox virus infection; this proportion has remained stable over time.

No deaths have been reported to date.

The distribution of cases by date of symptom onset (when known) and case type (biologically confirmed or not) is shown in Figure 3. The date of symptom onset for these cases ranges from May 7, 2022, to March 12, 2023. Due to reporting delays, data from the most recent weeks have not yet been consolidated. The reports received do not always mention the date of symptom onset. As an alternative to this information, the distribution of cases by date of reporting is presented in Figure 4.

Figure 1. Total monkeypox cases (n = 4,973) by region of residence (or by region of reporting when the region of residence is unknown), France, May 2022–March 2023 (data as of March 23, 2023 – 12:00 p.m.)

Figure 1. Cas de variole du singe totaux (n= 4 973 cas) par région de résidence (ou par région de signalement lorsque la région de résidence est inconnue), France, mai 2022-mars 2023 (données au 23/03/2023 – 12h00)

Figure 2. Biologically confirmed cases (n = 4,122) by region of residence (or by region of reporting when the region of residence is unknown), France, May 2022–March 2023 (data as of March 23, 2023 – 12:00 p.m.)

Figure 2. Cas confirmés biologiquement (n= 4 122) par région de résidence (ou par région de signalement lorsque la région de résidence est inconnue), France, mai 2022-mars 2023 (données au 23/03/2023 – 12h00)

Figure 3. Monkeypox cases (n = 3,779 cases, number of missing data = 1,221) by week of symptom onset and by case type (biologically confirmed or not), France, May 2022–March 2023 (data as of March 23, 2023 – 12:00 p.m.)

Figure 3. Cas de variole du singe (n= 3 779 cas, nombre de données manquantes = 1 221) par semaine de début des symptômes et selon le type de cas (confirmé biologiquement ou non), France, mai 2022-mars 2023 (données au 23/03/2023 – 12h00)
The data for the past three weeks has not yet been fully consolidated.

Figure 4. Monkeypox cases (n = 4,998 cases, number of missing data points = 2) by week of reporting and by case type (biologically confirmed or not), France, May 2022–March 2023 (data as of March 23, 2023 – 12:00 p.m.).

Figure 4. Cas de variole du singe (n= 4 998 cas, nombre de données manquantes = 2) par semaine de signalement et selon le type de cas (confirmé biologiquement ou non), France, mai 2022-mars 2023 (données au 23/03/2023 – 12h00).
The data for the past week has not yet been fully consolidated. The dip in reported cases observed in week 28 (July 11–17) can be attributed to the July 14 holiday.

Clustered cases in the Centre-Val de Loire region, January–March 2023

Between January 1, 2023, and March 23, 2023, 17 confirmed cases in males were reported in the Centre-Val de Loire region, including 14 since March 1, 2023.

The investigation revealed that all of these cases involved men who have sex with men (MSM), several of whom reported having had multiple partners but were not always able to identify them. No parties or events common to the cases were identified.

The cases range in age from 24 to 56 years (median age of 40). The clinical characteristics of these cases remain similar to those previously observed; no cases required hospitalization.

Six of the 17 cases had not received any smallpox vaccination, 1 reported an incomplete vaccination history (childhood vaccination with a first-generation smallpox vaccine), and 10 reported a complete vaccination history: 5 with a first-generation smallpox vaccine in childhood + 1 dose of a third-generation vaccine in 2022, and 5 with 2 doses of a third-generation vaccine in 2022.
Given the high proportion (59%) of vaccinated individuals in this cluster, investigations were conducted by Santé publique France and the Regional Pharmacovigilance Center in Tours. The proportion of vaccinated cases is higher than what is observed at the national level (25% of male mpox cases reported between October and February 2023 in France involved vaccinated men). We must await the results of real-world efficacy studies, which will allow for a better interpretation of these data. To date, there is limited long-term data on the efficacy of third-generation vaccines against mpox infection. There are no data on long-term protection following a full vaccination series, nor in specific population subgroups. These vaccines are subject to pharmacovigilance monitoring coordinated by the ANSM. To date, no safety concerns have been raised regarding the quality or safety of these vaccines.

This episode suggests, at this stage, localized transmission in the Touraine region, against a backdrop of virtually no reported cases in the rest of the country. Among the reported cases, some have indicated high-risk contacts and exposures in other regions, particularly in the Île-de-France region.
After a week without any reports, a new case was reported on March 24 and is currently under investigation.

Pending robust data on the real-world efficacy of mpox vaccines, this cluster calls for vigilance. Mpox infections can occur in individuals who have received a full course of vaccination, and it is important to consider this diagnosis in cases of skin or mucosal rashes, including in properly vaccinated individuals. Mpox surveillance requires that vaccination status be collected for all notifiable mpox cases.

At this stage, this outbreak suggests localized transmission in the Touraine region, against a backdrop of virtually no reported cases in the rest of the country. Prevention recommendations remain in effect, particularly avoiding sexual contact if lesions suggestive of mpox are present and using condoms for 2 months after recovery. Vaccination remains recommended and remains effective in the majority of people who have received a full vaccination series to prevent the risk of infection. It is important to ensure that eligible individuals*, including MSM with multiple partners, are up to date on their mpox vaccination. For individuals born before 1979, in the absence of proof of smallpox vaccination in their immunization record or a characteristic scar, it is recommended that they receive a second dose of the third-generation vaccine.

After the peak in infections reached in late June/early July, the number of cases dropped sharply—whether biologically confirmed or unconfirmed—and very few cases were reported between November 2022 and February 2023. However, some cases may not have sought medical care and may therefore not have been diagnosed or reported.

This low apparent incidence is also observed globally, with about 100 cases reported each week, and fewer than 10 in Europe over the past 3 weeks (https://worldhealthorg.shinyapps.io/mpx_global/).

Pending robust data on the real-world effectiveness of mpox vaccines, the cluster currently being monitored in the Centre-Val de Loire region calls for vigilance as the season of international MSM festivals and Pride parades approaches. Prevention recommendations remain in effect, particularly avoiding sexual intercourse if lesions suggestive of mpox are present, and using condoms.

Mpox infections can occur in people who have received a full course of vaccination, and it is important to consider this diagnosis in cases of lesions typical of mpox, including in properly vaccinated individuals. Mpox surveillance requires that vaccination status be collected for all mpox cases subject to mandatory reporting.

Information and Prevention Initiatives

Sexosafe (sexosafe.fr) continues to address mpox infection on its social media accounts to keep the topic relevant to the relevant audiences.
Additionally, posters and flyers encouraging self-monitoring of symptoms and vaccination are still available.

To order them:

  1. Go to https://moncoupon.santepubliquefrance.fr/

  2. Log in to your account or create one

  3. Enter the following campaign code: MPOX2023

  4. Select the desired documents and confirm your order

Only one order per person. Campaign valid through 12/29/2023. While supplies last.

* Opinion of July 7, 2022, from the Board of the French National Authority for Health regarding pre-exposure vaccination against monkeypox for individuals at high risk of exposure
https://has-sante.fr/jcms/p_3351308/fr/avis-n2022-0039/ac/sespev-of-July-7-2022-from-the-College-of-the-Haute-Autorité-de-Santé-regarding-pre-exposure-vaccination-against-the-monkeypox-virus-for-individuals-at-high-risk-of-exposure

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