At least 46 children have died in an explosive outbreak of measles in Bangladesh, prompting the authorities to lower the vaccination age to six months.

Some 684 measles cases have been confirmed in Bangladesh since the outbreak began in late January, with most of them coming in March.

The disease is spreading rapidly in densely populated urban areas and hospitals are struggling to cope with the influx of patients, the country’s health authorities say.

The decision to alter the vaccination schedule followed a recommendation by Bangladesh’s National Immunisation Technical Advisory Group (NITAG), which noted that more than a third of the cases confirmed so far were in infants younger than nine months, when the first of two doses of the measles jab is usually given.

Under the existing programme, aligned with World Health Organization (WHO) guidelines, children receive their first Measles-Rubella jab at nine months and a second at 15 months.

That schedule will be retained for routine immunisation, but a special nationwide campaign, expected to begin in early June, will extend eligibility to younger infants, said Halimur Rashid, director of disease control at the Directorate General of Health Services (DGHS).

Dr Tajul Islam A Bari, a Dhaka-based immunologist, said the decision to lower the age for vaccines was a necessary intervention but will mean a fall in effectiveness.

“In outbreak or disaster situations, vaccination can be given earlier than nine months, but the effectiveness is significantly lower,” Dr Bari said. “At nine months, about 85 per cent of children develop immunity. At six months, effectiveness drops to below 50 per cent.”

Measles is a highly contagious disease that primarily affects children and spreads rapidly through respiratory droplets. Its symptoms include high fever, cough, runny nose, and a characteristic skin rash. In severe cases, it can lead to pneumonia and even to death, particularly among unvaccinated children.

Dr Ziauddin Hyder, Health Advisor to the Prime Minister of Bangladesh, told The Telegraph that 46 deaths have now been linked to measles.

The actual number of deaths could be higher because of lack of comprehensive data on measles-related deaths, an official at the DGHS said.

“This situation can’t be taken lightly. It reflects deeper systematic challenges within our health system, including problems that didn’t emerge overnight,” Dr Hyder said. “As of today, a total of 2,268 children have been hospitalised with suspected measles, including 168 new infections [on Tuesday].”

During the same period last year the number of reported cases was 68.

At Dhaka’s Infectious Disease Hospital, wards have filled with young children suffering from high fever, pneumonia, and dehydration.

The health authorities have launched an investigation into the origin of the outbreak, as concerns grow that a disease that was once largely under control is re-emerging.

Health officials say the outbreak has been driven in part by falling vaccination coverage and delays in mass immunisation campaigns.

Bangladesh last conducted a nationwide measles campaign in 2020. A planned follow-up in 2024 did not take place amid political unrest, leaving many children unprotected.

In 2025, the first-jab coverage dropped to 56.5 per cent and second to 57.1 per cent, nearly half of previous levels, creating what public health experts described as a pool of vulnerable children.

Sardar Muhammad Sakhawat Hossain, Bangladesh’s Health and Family Welfare Minister, said the failure of immunisation campaigns in recent years has left many children unprotected.

“Most cases are being reported among those who have not received the vaccine,” Mr Hossain said.

The government plans to vaccinate up to 20 million children aged between six months and five years during the emergency campaign, with the age range extended to ten years in high-risk districts.

However, delays in getting hold of supplies, particularly syringes, have slowed the rollout, despite vaccines already being made available through the Gavi global vaccine partnership.

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