The centre was cleared of people last week after reports of overcrowding and disease.
The death of a migrant held at the Manston processing centre in Kent may have been caused by diphtheria, the Home Office has said.
The man died in hospital on 19 November after entering the UK on a small boat seven days earlier, it is understood.
The centre was cleared of people last week after reports of overcrowding and outbreaks of disease.
Hospital tests indicate “diphtheria may be the cause of the illness”, according to a Home Office spokesperson.
Initial hospital tests processed by a local hospital were negative and the Home Office said there was “no evidence at this stage” that the person had died from an infectious disease.
But a follow-up PCR test for diphtheria has since produced a positive result.
Diphtheria is a highly contagious infection that affects the nose, throat and sometimes cause ulcers on the skin.
According to the NHS website, it’s spread by coughs and sneezes or through close contact with someone who is infected.
You can also get it by sharing items such as cups, cutlery, clothing or bedding with an infected person.
The UK Health Security Agency (UKHSA) said 39 diphtheria cases had been identified in asylum seekers in England this year up to 10 November.
Manston – a former military base – is designed to hold just 1,600 people. But in October there were around 4,000 migrants being held there.
More than 40,000 migrants have crossed the Channel on small boats this year.
Home Secretary Suella Braverman told the Home Affairs Select Committee that the Government had “failed to control our borders”. She also blamed migrants and people smugglers for the chaos at Manston.
A Government spokeswoman said: “Our thoughts remain with the family of the man who has died and all those affected by this loss.
“We take the safety and welfare of those in our care extremely seriously and are taking all of the necessary steps following these results.
“We are offering diphtheria vaccinations to people at Manston.”
A post-mortem examination and a coroner’s investigation into the man’s death are ongoing.