Two people were diagnosed with smallpox in London, paramedics said on Saturday.
The couple live in the same household and are not linked to a previous confirmed case in England, which was announced on May 7, the UK Health Security Agency (UKHSA) said.
In the last two cases, one person is receiving care from the Infectious Diseases Unit at St Mary’s Hospital, Imperial College Healthcare NHS Trust in London.
The other person is in solitary confinement and does not currently require hospital treatment, the UKHSA said.
Paramedics said they were investigating where and how the latest cases of monkeypox had become infected.
People who may have been in close contact with both cases are being contacted and provided with information and medical advice, the UKHSA said.
Colin Brown, director of clinical and emerging infections at UKHSA, said: “We have confirmed two new cases of monkeypox in England that are unrelated to the case reported 7.
“While investigations are still ongoing to determine the source of the infection, it is important to emphasize that it does not spread easily among people and requires close personal contact with the infected symptomatic person. The overall risk for the general public remains very low.
“We contact all potential friends, family or contacts in the community. We also work with the NHS to reach all health contacts who have had close contact with cases before their infection is confirmed, to evaluate them and provide advice as needed.
The first case of monkeypox in the United Kingdom was reported in September 2018 in an individual believed to have become infected in Nigeria.
It is a rare viral infection that does not spread easily to humans and is usually a mild disease that resolves on its own, but some people may suffer from a serious illness.
Initial symptoms include fever, headache, muscle aches, back pain, lymph node swelling, chills and exhaustion.
A rash may also develop, which usually begins on the face before spreading to other parts of the body. Eventually, it forms a scab that falls off.
Dr Colin Brown, director of clinical and emerging infections at UKHSA, said: “It is important to emphasize that smallpox does not spread easily among humans and the overall risk to the general public is very low.”
On Friday, medics in Scotland revealed that they were involved in monitoring a “small number of individuals” associated with an earlier case of monkeypox smallpox found in England.
On Saturday, May 7, a case of monkey pox was reported south of the border in a patient with a recent travel history from Nigeria, a place where he is thought to have contracted before traveling to the United Kingdom.