Toddler, 3, died after catching disease 70 per cent of children contract as devastated parents warn others

The family of a toddler who "didn't have an immune system" say he died after contracting a disease which 70 per cent of children catch by the age of three. Raffy Holliday passed away aged three after contracting herpes, his parents said.

Following his death at Great Ormond Street Hospital (GOSH), they are now campaigning to increase testing for the human herpesvirus 6B (HHV-6B) in hospitals. About 70 per cent of children contract HHV-6B by the age of three, but most develop a natural immunity which prevents further reinfection, The Mirror reports.

However reactivation of the virus is common in transplant patients and can be fatal for those with weakened immune systems. Raffy passed died after suffering inflammation of the brain caused by HHV-6B.

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HHV-6B is one of nine strains of the herpesvirus and is the cause of the common childhood illness exanthema subitem, also known as roseola or sixth disease, which causes a mild fever and rash. The toddler, who was undergoing treatment for leukaemia and had received a bone marrow transplant, lived with the active virus for two years before it took his life.

After his transplant in 2020, he was tested on a weekly basis for three other strains of the human herpes virus - Epstein Barr which causes glandular fever, cytomegalovirus which causes mononucleosis, and adenovirus which causes the common cold. Raffy's mum Imogen Holliday, 35, says she was told by medics he would not be routinely tested for the HHV-6B strain unless he become neutropenic - when a type of white blood cell called neutrophils drop below a certain level, severely weakening the immune system.

This is despite the fact that the three-year-old was