A more deadly strain of Mpox has ventured beyond African borders, but even though it will arrive here some time, there's no need to panic.

A new strain of Mpox has been found outside its country of origin but a health expert here says there's no need for Kiwis to panic.

The World Health Organisation (WHO) has declared the outbreak of Mpox Clade 1 in Central Africa a public health emergency of international concern.

Health experts believe it's more transmissible and more severe than the Clade 2 strain that's already spread globally.

So far 96 percent of the cases are in the Democratic Republic of Congo, but infection is spreading rapidly in neighbouring countries. Two cases have been detected in Pakistan, and one in the Philippines. On Thursday Sweden reported its first case, and its health agency confirmed the person contracted the virus during a recent stay in Africa and is now isolating.

It sounds alarming but an infectious disease expert from the University of Auckland says we don't need to be stockpiling toilet paper just yet.

New Zealanders should be keeping an eye on how the outbreak develops but Associate Professor Mark Thomas thinks it will be some time before it gets here.

"It won't be an overwhelming number of cases to begin with and likely public health efforts assisted by vaccination will bring it under control relatively quickly. By that, I would think within a month or two," he says.

The main point of concern is the severity of Clade 1, and its higher death rate which is 10 percent. The other variant is found in West Africa and has a lower death rate of about one percent.

But those death rates are based on case and death figures from the African countries where the virus originates.

Thomas says during the last global spread of Mpox Clade 2 a couple of years ago, other countries didn't record the same mortality rates.

And that could be for several reasons. One is that some countries may be less rigorous with reporting, which makes the mortality rate skew higher.

In Africa, "people with mild cases don't bother going to a health professional and don't get recognised as having Mpox. Whereas New Zealand, Sweden, UK, the States, it might be that a much higher proportion of people go, including those ones with very mild illness," he says.

What is Mpox?

Mpox is a viral infection that's closely related to smallpox. It used to be referred to as Monkeypox because initially scientists thought it was a virus that particularly affected monkeys…

Go to this episode on rnz.co.nz for more details