The patient, only the second in the United Kingdom to be diagnosed with the rare viral infection, was quarantined before being transferred to Liverpool, which specialises in tropical diseases - and bosses at the Vic have moved to stress patients, staff, and visitors are no longer at risk.
The unit has "highly trained staff who are experienced in dealing with a variety of infectious diseases", he added.
"It is likely that monkeypox continues to circulate in Nigeria and could, therefore, affect travellers who are returning from this part of the world", Phin.
Dr Nick Phin, deputy director of the national infection service at PHE, said it was "very unusual" to see two cases so close together.
Although monkeypox is much milder than smallpox, with most infected people recovering within a few weeks, it can in rare cases be fatal. The first human case was recorded in 1970 in the Democratic Republic of Congo.
PHE said they were contacting a number of people who may have been in contact with the patients, including fellow passengers who traveled with the initial patient on their flight from Nigeria.
Infected people usually start to show symptoms between five and 21 days after infection.
A painful rash with open sores can develop, often beginning on the face, then spreading to other parts of the body. It eventually forms a scab which falls off.
Chikwe Ihekweazu, chief executive of NCDC, said the agency met with stakeholders recently, including surveillance officers and case management physicians from all states affected in the last outbreak of the virus, to strategise on how to strengthen the country's response. "We are working hard to contact individuals, including healthcare workers, that might have come into contact with the individual to provide information and health advice", he said.
Dr Mike Beadsworth, clinical director of the Tropical and Infectious Diseases Unit at the Royal Liverpool University Hospital, a specialist centre in respiratory infectious diseases, said: 'We are treating a patient who has tested positive for monkeypox.
"All necessary precautions are being taken".
The disease was first discovered in monkeys kept for research in 1958.