The declaration of the monkeypox outbreak as a global emergency is recognition of the need for worldwide efforts to investigate and prevent further spread of the disease, UK health experts have said.

The World Health Organisation (WHO) said on Saturday that the spread in more than 70 countries is an “extraordinary” situation.

The UK Health Security Agency (UKHSA) said the risk to the UK remains the same as before the declaration, and a professor at the London School of Hygiene and Tropical Medicine (LSHTM) reassured people the situation is not something they should “unduly worry” about.

This week, the NHS announced it was stepping up its NHS vaccination programme against monkeypox in London as more supplies of a jab become available.

On Tuesday, the UK Health Security Agency (UKHSA) said it had procured 100,000 more doses of an effective vaccine.

As of July 21, there were 2,208 confirmed cases in the UK, of which 2,115 were in England.

While anyone can get monkeypox, the majority of cases in the UK continue to be in gay, bisexual and other men who have sex with men.

Vaccination experts have recommended that gay and bisexual men at higher risk of exposure to monkeypox should be offered the smallpox vaccine Imvanex.

Dr Meera Chand, director of clinical and emerging infections at UKHSA, said the WHO declaration of an emergency “recognises the rapid spread of the virus globally, and the need for global coordination to investigate and prevent further transmission”.

Dr Chand added: “The UK continues to  work closely with the World Health Organisation, and to share our clinical and epidemiological findings and public health approach to the outbreak.

“The risk to the UK remains the same. If you have monkeypox symptoms, take a break from attending events or sex until you’ve called 111 or a sexual health service and been assessed by a clinician.

“It can take up to three weeks for symptoms to appear after being in contact with someone with monkeypox, so stay alert for symptoms after you have skin-to-skin or sexual contact with someone new.”

WHO director-general Tedros Adhanom Ghebreyesus made the decision to issue the declaration despite a lack of agreement among experts serving on the UN health agency’s emergency committee.

While a global emergency is WHO’s highest level of alert, the designation does not necessarily mean a disease is particularly transmissible or lethal, and can be a call for more resources and attention to be focused on an outbreak.

The declaration should be a “stark reminder to world leaders” of the globe’s vulnerability to outbreaks of infectious disease, said an expert based at the Wellcome science organisation, which has its headquarters in London.

Dr Josie Golding, head of epidemics and epidemiology at the foundation, said: “With monkeypox cases continuing to rise and spread to more countries, we now face a dual challenge: an endemic disease in Africa that has been neglected for decades, and a novel outbreak affecting marginalised communities.

“Governments must take this more seriously and work together internationally to bring this outbreak under control.”

She said governments need to support more research to understand why there are new patterns of transmission, evaluate the effectiveness of current tools and support the development of improved interventions.

She added: “Without this swift and concentrated action, monkeypox will continue to infect even more people unnecessarily and become established in more populations, including the risk of reverse spillover into animals.

“We cannot afford to keep waiting for diseases to escalate before we intervene.”

Professor Jimmy Whitworth, of LSHTM, said the continued spread of the disease indicates that measures which have put in place have not been sufficient to control the spread of the infection – but urged people not to worry too much.

He said: “This outbreak is concerning for public health practitioners around the world as it has proved very challenging to prevent onward transmission of infection, but it is not a situation that should unduly worry the general public.

“This is an infection that is transmitted by close contact – touching skin, coughing and sneezing, sharing of utensils, bedding and so on. The vast majority of cases have been in gay, bisexual or other men who have sex with men who have had multiple recent sexual partners.

“Most people, whatever their sexual orientation, do not have close contact of this sort with many people and so the infection is unlikely to spread easily.”

He added that increased attention on the disease might “lead to more focus on control within Africa,  the natural home of this virus, where the number of cases has been increasing for the past 20 years”.