French health authorities have launched an investigation after 59 per cent of people in a new mpox cluster said they were fully vaccinated.
Vaccination does not offer complete protection against the virus – though only one in four French cases are usually in immunised people.
Mpox, formerly known as monkeypox, can cause and unusual spots, ulcers or blisters anywhere on the body; fever; headaches; muscle aches; chills; fatigue and swollen glands.
Though most people have a mild illness, with recovery within three weeks, some cases can cause severe illness and occasionally result in death.
Mpox is not normally a sexually-transmitted infection, but it can be passed on by direct contact during sex.
The cluster in France’s Centre-Val de Loire comes despite the region having a high vaccination rate, with experts warning of a potential mutation in the virus.
The mpox vaccine is not tailored to the disease and was originally created to protect against smallpox. Last year, the UK Health Security Agency (UKHSA) recommended offering Imvanex to those at increased risk of exposure to the virus.
Dr Michael Marks, Associate Professor at the London School of Hygiene and Tropical Medicine, told the Telegraph that health authorities may need to investigate whether a mutation has affected the vaccine’s efficacy.
He also noted that many mpox cases have been reported in people with HIV.
“HIV may modify how effective the vaccine is. We don’t know the HIV status of this cluster at the moment.”
France’s public health body, Sante Publique France, have said they are investigating the cluster and are waiting for “robust data” on the efficacy of the vaccine.
Mpox can also be spread through touching clothing, bedding or towels used by someone with the mpox rash, and through the coughs and sneezes of somebody with the infection.
An outbreak of the disease in London and other British cities made headlines last year – though infections have slowed following a targeted vaccination programme.
The outbreaks raised alarm because the viral disease, which spreads through close contact and was first found in monkeys, mostly occurs in west and central Africa and only occasionally spreads elsewhere.
Over 25,800 cases have been reported in Europe since spring 2022, mostly among men who have sex with men.
