Free at centres nationwide. Officials said necessary medicines and equipment have been stocked at district and upazila levels, and a hotline is available for emergencies.

Experts believe strengthening primary healthcare would ease pressure on large hospitals, and urged that community clinics be made more effective.

Public health experts say awareness and prevention are the most effective tools against the immunisation programme. They advise visiting the nearest health centre without delay if even mild symptoms appear.

According to hospital data, outpatient departments have been busier over the past few weeks. Doctors say most patients recover with primary treatment.