Health officials investigating a deadly outbreak of a rare fungal meningitis have urged doctors and hospitals across 23 states to contact patients who may have received a contaminated steroid injection in the last three months, in order to check them for symptoms.

The rapidly evolving outbreak has already killed five people and a further 35 are ill in six states, some of them “very seriously”.

Officials, who have focused their investigations on an injection made by the New England Compounding Center (NECC), in Massachusetts, have expanded a recall and warned physicians, hospitals and clinics not use any products which may have come from the company.