Risk of mpox being ‘confused with chickenpox’ after new killer strain detected in the UK – how to spot the difference
A NEW strain of the mpox virus has been detected in the UK, and now an expert has warned not to confuse the symptoms with chickenpox.
Three people in the UK have been found to be infected with the clade 1b mpox variant, which was first detected in central Africa and appears to transmit more easily between people.
Mpox viruses are divided into different clades – clade 1 is typically found in central Africa and clade 2 in western parts of Africa. Clade 1 is further subdivided into the clades 1a and 1b.
Mpox causes the typical symptoms of an infectious disease, including flu-like symptoms, a high temperature/fever, headaches, tiredness, and swollen lymph nodes.
This is typically followed by a rash that is initially characterised by small spots, which then progress into pus-filled blisters.
The rash normally lasts between two and four weeks.
But at the start of an infection, it might not be straightforward to differentiate between mpox and other infectious diseases.
Professor of Molecular Medicine, Martin Michaelis, from the University of Kent’s School of Biosciences, warned there’s sometimes a risk mpox may be confused with chickenpox.
He explained: “These are different diseases caused by different, unrelated viruses. Mpox is caused by a poxvirus that is related to the smallpox virus that was successfully eradicated in the last century and the vaccinia virus that was used as a vaccine virus for the eradication of smallpox.
“In contrast, chickenpox are caused by the Varizella Zoster virus, which is a herpes virus that is closely related to the herpes simplex viruses that cause cold sore.”
How to tell the difference between mpox and chickenpox
The most characteristic and recognisable symptom of mpox is the rash. Although it’s important to note this may take a few days to develop.
The NHS says the first symptoms of mpox to appear are:
- A high temperature (fever)
- A headache
- Muscle aches
- Back ache
- Swollen glands
- Shivering (chills)
- Exhaustion
- Joint pain
A rash is also the main symptom of chickenpox. But Prof Michaelis advised: “Mpox lesions are usually larger and more painful, whereas chickenpox lesions tend to be smaller and itchy.”
Other symptoms of chickenpox include:
- A high temperature
- Aches and pains and generally feeling unwell
- Loss of appetite
The mpox rash typically lasts two to four weeks, while the chickenpox rash lasts about five to 10 days.
Mpox can be readily transmitted via close person-to-person contact and via contaminated materials, such as clothes, bedding, and towels.
So infected individuals should avoid contact with others as long as they have symptoms.
What to do if you think you have mpox symptoms
You should isolate yourself and get tested, so that contacts that you might have infected can be identified, said Prof Michaelis.
He added: “There is no established specific antiviral treatment. A drug called tecovirimat is under investigation, but the evidence on its efficacy is mixed.
“Hence, treatment is typically symptomatic and focused on controlling pain and fever.”
Can an mpox infection become serious?
Serious disease and deaths have been recorded. But it remains unclear how big the risk is in a country with a well-developed health system like the UK – children are generally at a higher risk.
Prof Michaelis said: “Vaccines are available that should enable us to get mpox under control, if it keeps spreading.
“The risk that new mpox viruses emerge that can escape immune protection provided by the vaccines is much smaller than for COVID-19, because the mpox virus mutates much less than SARS-CoV-2, the coronavirus that causes COVID-19.
“Nevertheless, every mpox virus infection is still associated with a risk of the formation of viruses that are more dangerous.
“Hence, it would be prudent to suppress the mpox spread as much as possible, ideally starting in Africa, where we have already seen tens of thousands of cases and about 1,000 deaths.”
If you think you have mpox symptoms, as well as staying home and avoiding close contact with other people, contact a sexual health clinic or NHS 111.
Who can get the mpox vaccine?
The NHS is offering the smallpox (MVA) vaccine to people who are most likely to be exposed to mpox.
People who are most likely to be exposed include:
- Gay, bisexual, or other men who have sex with men (GBMSM)
- Some health workers that work on infectious disease inpatient units and sexual health services
- Some health and aid workers travel to affected countries to work within mpox response or sites with active outbreaks
- Close contacts of confirmed cases
The NHS mpox outbreak vaccination programme is currently only available in London and Greater Manchester, to people who live or travel to have sex there.
Healthcare workers will usually be offered two doses of the vaccine.
Men who are gay, bisexual or have sex with other men will be offered 2 doses of the vaccine. The 2nd dose will be offered from 2 to 3 months after the 1st dose.
Your local NHS services will contact you when you can get your 2nd dose.