A nurse who disappeared after taking part in a medical trial for malaria may have travelled abroad, police say.
Matthew Lloyd was reported missing on 7 October after he missed an appointment for treatment in Oxford as part of a test to find a cure for the disease. He had been to his previous appointment on 1 October in London, where he was infected with malaria, and he now needs urgent medication for the condition.
Police have previously issued a CCTV image of the last confirmed sighting of Mr Lloyd, 35, near King's Cross station in London. Detectives now believe the 35-year-old, from Shirley, Southampton, may have travelled abroad after inquiries suggested he was carrying his passport and £900 in cash.
Detective Inspector Becky Riggs, of Hampshire Police, said: "Despite repeated appeals for information and extensive coverage highlighting his disappearance, Matthew has still not been found and we have had no confirmed sightings of him in the UK.
"The fact that there are no leads relating to his whereabouts suggests to me he may have got the treatment he needs for the malaria virus or has potentially gone abroad. This is just one possible explanation and we have no evidence to suggest where he might have gone.
"Prior to participating in the trials, Matthew was well briefed on malaria, signs, symptoms and treatment. He is a qualified nurse and he would have known the dangers of malaria. I have confidence in his training and the brief he has received from his trial."
Earlier this week, Mr Lloyd's family said his disappearance was out of character. As well as having gone to Oxford for the clinical trial, Mr Lloyd is known to have links with Cornwall, Avon and Somerset.