It is unlikely New Zealand will be hit with a large outbreak of monkeypox, especially if its genome sequence hasn't changed since it was first discovered, an expert says.
Otago University Professor of Biochemistry Kurt Krause says it's unlikely the genome sequence of monkeypox has changed since 1970. Photo:
More than 80 cases have been confirmed in the recent outbreak in Europe, the US, Canada and Australia.
Israel, Switzerland and Austria are the latest countries to confirm cases, bringing the total number of nations reporting outbreaks to 15.
Monkeypox does not tend to spread easily between people and the illness is usually mild, especially in countries with good health systems.
The virus is most common in remote parts of Central and West Africa.
University of Otago Professor of Biochemistry Kurt Krause told Morning Report that monkeypox is a pox virus, a relative of chickenpox and and also smallpox, the devastating disease that was eradicated in 1980 through the use of vaccines.
The first known human transmission of monkeypox occurred in 1970 and since then there have been sporadic outbreaks, including in the United States in 2003 and a relatively large outbreak in Nigeria in 2017, he said.
"So these outbreaks happen - they tend to have 100 to 200 people and usually they fizzle out after that. It's unusual to have very large outbreaks."
In the current outbreak, the first 50 cases have been linked to a man who travelled to Africa and then took monkeypox back to Europe.
"By and large it appears to be linked to that initial case and it's people who got the illness and then travelled widely while they were incubating the illness."
Professor Krause said these new infectious illnesses crop up every couple of years but people have a heightened awareness of them now because of the Covid-19 pandemic.
He said it will be important to get the facts and figures and study the genome of the present cases.
"If the genome hasn't changed and it's the same monkeypox we've been seeing since 1970 the likelihood of it causing a huge outbreak here is remote.
"If the genome shows it's radically different then that's another thing altogether but pox viruses actually have very stable genomes so it would be very unusual to find that to be the case."
"Pox viruses actually have very stable genomes" Professor of Biochemistry Kurt Krause
Monkeypox is vastly different from coronavirus, because it is far less contagious, Professor Krause said.
While the infection rate for Omicron is in the 10-15 range, for monkeypox the range is less than one.
"So generally speaking, if somebody has monkeypox they usually don't pass it off to anybody."
An illustration of pox virus that include smallpox and monkeypox. Photo: AFP
As well, a vaccine is already available - the one that was developed for smallpox is about 85 percent effective and there are also anti-virals that can be used.
For most people if they had a smallpox vaccine many years ago their immunity will have reduced by now, he said.
He would not be surprised to see a few cases in Aotearoa, however, it is unlikely mass vaccinations would be needed.
Generally, a person with monkeypox should isolate and once the lesions that are a symptom of the virus have crusted over the person is no longer considered infectious, Professor Krause said.
Read this explainer on monkeypox for more information on the virus
Professor Michael Baker said monkeypox was a fascinating disease.
Every year there were thousands of cases occurring in Africa but it was highly unusual for it to spread in large numbers to high income countries.
There also appeared to be some asymptomatic cases so "that's a concern".
While Professor Baker expects to see a few cases crop up in New Zealand, he does not view it as a huge health threat.
"It's far less transmissible than something like Covid-19 and the outcome is not particularly severe with this infection."
The West African variant of monkeypox that has been detected in the current outbreak has a fatality risk of 1 percent in African countries but in those countries with good healthcare systems it is far less dangerous, Prof Baker said.
"It's far less transmissible than something like Covid-19" Professor Michael Baker
Fourth dose from June?
It is likely people who are more vulnerable (older people, people with immune-suppressive illness) will be able to receive a fourth Covid-19 vaccine dose from June, Professor Baker said.
The number of new Covid-19 cases yesterday dropped below 5000 for the first time in three months.
Prof Baker said case numbers have started to plateau but have risen 75 percent in the last four weeks in Auckland and are expected to climb higher nationwide over winter.
"At the moment there are more forces favouring the virus than holding it back."
He told First Up modelling is showing the country is likely to see quite a big upsurge over winter.
Professor Baker said the most vulnerable - such as older people and those who are immune suppressed - are likely to soon be offered extra vaccine protection probably starting next month.
"It's far less transmissible than something like Covid-19" Professor Michael Baker