Mpox has been declared a global public health emergency with scientists claiming the latest outbreak, which has now spread from Africa to Europe and Asia, more closely resembles the early days of HIV than Covid-19.

Known as monkeypox until it was renamed by the World Health Organization (WHO) in 2022 after complaints it was misleading as well as "racist and stigmatising", mpox is a viral disease related to smallpox. It causes flu-like symptoms and skin blisters across the body.

Most cases are "mild", said Sky News, but it can be "deadly" as it can lead to sepsis. There are currently no approved treatments specifically for mpox infections, according to the US Centers for Disease Control and Prevention (CDC), although two vaccines have been approved for emergency use by WHO.

A new more deadly Clade 1b sub-variant, first identified last September, has already killed more than 500 people in the Democratic Republic of the Congo (DRC), with cases also reported in more than a dozen neighbouring countries. Last week, Sweden confirmed the first case of the more contagious strain outside Africa, and another case was then reported in Pakistan. At that point WHO declared a "public health emergency of international concern", the category for Ebola outbreaks, Covid-19 and a 2022 mpox surge in Europe.

Unlike the mpox outbreak that spread globally in 2022, the newer strain is "more dangerous", said Bloomberg. The current variant has a case fatality rate between 3% and 5%, considerably higher than Covid-19.

Evidence also suggests the incubation period - the length of time someone who has contracted mpox can transmit the virus before they develop symptoms - could be as long as four days, "making it harder to contain by identifying and isolating cases". A 2022 study from the UK found that more than half of mpox infections were spread by infected individuals who had not yet developed symptoms.

But while the latest outbreak has understandably sparked concern, said Kiffer George Card, an epidemiologist writing on The Conversation, the WHO's public health warning should, at this point, "raise caution, not cause panic".

Unlike Covid, mpox is not a respiratory disease and is instead transmitted via prolonged skin-to-skin contact, sexual intercourse or passed to children during pregnancy or after birth. This means the reproduction (R) number is significantly lower, making efforts to stop the exponential spread of the virus much easier.

While this is "far and away the biggest outbreak of mpox ever, with quite a high fatality rate", Professor Michael Marks from the London School of Hygiene & Tropical Medicine told The Guardian, "it's not likely to lead to a Covid-19 style pandemic.

"There will be concerns about its spread in countries with more resources, but it's chiefly going to be a problem in the region."

Although mpox has been around for decades, there are still "many unknowns" about how the virus spreads and why it suddenly appeared around the world in 2022, said Vox. "What researchers do know is that the virus has been rapidly mutating in recent years."

In this sense it more closely resembles "the early days of HIV", Trudie Lang, a professor of global health research at Oxford University, told The Guardian. The virus appeared to be spreading via sexual networks, with "vulnerable, young, exploited sex workers" at high risk.

Sweden's Public Health Agency, which confirmed Europe's first case of Clade 1b last week, said it has a "preparedness to diagnose, isolate and treat people with mpox safely". The "fact that a patient with mpox is treated in the country does not affect the risk to the general population, a risk that the European Centre for Disease Prevention and Control (ECDC) currently considers very low".

Asian countries have also "beefed up surveillance", said Bloomberg, after Pakistan confirmed an mpox infection last week. China is asking incoming travellers from countries and regions affected, as well as individuals experiencing symptoms, to report to customs officials upon entry, while Economic Times reported health authorities in India, Indonesia and Malaysia have all ordered heightened vigilance at international airports and ports for passengers displaying mpox symptoms, and designated hospitals and labs to handle potential cases.

But while these international cases have "inevitably raised concerns about the further spread of the disease", The Guardian said it remains the case that those in the DRC and neighbouring countries are "most at risk - and are facing a severe challenge in securing urgently needed vaccines".