A four-month-old boy died after being found unconscious at his home in Sha Tin yesterday. The death occurred less than 24 hours after the infant, surnamed Tse, received his second round of vaccinations at a public health clinic on Monday as part of the government's immunisation programme. A doctor said it was 'highly unlikely' the death was caused by the injections. Police said it appeared Tse developed a fever and was given medicine during the night. The 24-year-old mother, surnamed Lee, found the boy unconscious in bed at the family's flat in Mei Lok House, Mei Tin Estate, and called police at 5.23am. He was taken to Prince of Wales Hospital and declared dead. Police said there were no signs of suspicious circumstances. A postmortem examination would be carried out. The Health Department said the boy had received his second doses of the diptheria, tetanus, whooping cough and polio vaccine and the pneumococcal conjugate jab at Lek Yuen Maternal and Child Health Centre. Paediatrician Alvin Chan Yee-shing said there was a one-in-1,000 chance of a baby dying suddenly but it was very rarely caused by vaccines. He said '99.5 per cent of babies receive injections almost once a month and it is possible that a sudden death occurs sometime after an injection'. He reminded parents that they should not sleep with their babies or let them lie on their stomachs while sleeping.