The HSE confirmed last night it does not yet have stocks of the vaccine.
Prof Sam McConkey, head of the Department of International Health and Tropical Medicine at the Royal College of Surgeons in Dublin, was speaking as the first person found to have monkeypox in Northern Ireland was diagnosed yesterday, but there is no known case in the Republic yet.
Prof McConkey said a supply of smallpox vaccines is important for certain health workers involved in treating patients, National Virus Laboratory staff and also close contacts of a confirmed case.
A spokeswoman for the HSE said last night that there is “currently no supply of the third generation smallpox vaccine, that is licensed by FDA for use in monkeypox, in Ireland”.
She said a special expert team, set up here to oversee the management of the virus, “are considering advice on vaccines and counter-measures and further information will be issued when available”.
Monkeypox has been made a notifiable disease here.
Observational studies of the smallpox vaccine suggest it is around 85pc effective in preventing monkeypox. It comes as the first case was confirmed by the Public Health Agency in the North yesterday. Details of the patient – who is understood to be in hospital – were not revealed.
Dr Michael McBride, the chief medical officer in Northern Ireland, said he is confident the virus will not become endemic in any of the places it has spread to outside of Africa.
There are currently 79 cases in the UK, including 76 in England, one in Scotland and one in Wales. However, given the level of international travel now under way, a case is expected in the Republic.
Prof McConkey said he would suggest giving the smallpox vaccine first to staff in the National Virus Reference Laboratory who are carrying out testing and also frontline healthcare workers who might need to treat infected patients .
“If you give it early on to close contacts of someone with monkeypox it can partly prevent them getting the disease or make it more mild,” he said. “In the first four days you can give it to family members, it can partly protect them.”
He said many countries are now looking for the smallpox vaccine and it could take a few weeks for drug companies to scale up the supply chain.
In 1863, the first vaccination against smallpox for all children born in Ireland was introduced.
Deaths caused by smallpox began to fall, until the last reported death from smallpox in Ireland was in 1907.
The smallpox vaccination stopped in Ireland in 1972. The World Health Organisation (WHO) declared smallpox eradicated worldwide in 1980.
Prof McConkey said that unlike Covid-19 it is a DNA virus and stable, leaving it less likely to mutate and be easier to catch. Currently, the chance of getting it is low.
Up to 10 suspect cases have proved negative here so far.
The incubation period is up to three weeks and there is still said to be a very low risk of it spreading.
In most cases, the form of monkeypox identified in Europe in recent weeks is self-limiting and has not caused any deaths although it can be a risk to groups such as people with very weak immune systems.
Prof McConkey said that he did not believe it was a sexually transmitted disease but people who are intimate can get close with skin-to-skin contact.
“If you are in the same bed with someone without sex you might still catch it,” he said.
The Health Protection Surveillance Centre said monkeypox spreads through close contact, including contact with the skin rash of someone with monkeypox.
“People who closely interact with someone who is infectious are at greater risk for infection: this includes household members, sexual partners and healthcare workers,” it said. “The risk of spread within the community in general is very low.”
Cases confirmed via PCR analysis need to be quarantined, either at home or in specialist hospital infectious disease wards. Their close contacts should be traced and ideally offered a smallpox vaccine.
Prof McConkey said those who are infected need to be in isolation for three weeks.