Bangladesh battles deadly measles outbreak as investigation highlights vaccination gaps

Bangladesh is facing a large measles outbreak that began in March 2026. By the time of the Reuters investigation, measles had killed 1,147 people and infected more than 202,000 others. The scale shows how quickly a preventable disease can become a national health crisis when vaccination protection falls.

Routine measles vaccination weakened in 2025. First-dose coverage dropped to 90 per cent, while second-dose coverage fell to 86 per cent. Both figures were below the 95 per cent level the WHO says is needed to prevent outbreaks. Political turmoil also disrupted health services, delayed vaccine orders and interrupted follow-up vaccinations.

Bangladesh responded with an emergency campaign that reached almost 20 million children in April and May. However, evidence suggested that millions were missed. A later campaign targeted 3.4 million children previously overlooked, while confirmed measles cases among unvaccinated children remained nearly unchanged after the first campaign.

Measles is a highly contagious viral disease that mainly threatens people without sufficient vaccination protection. The article focuses on children because they made up the target groups for Bangladesh’s vaccination campaigns and formed a large share of Nigeria’s confirmed cases. Measles can spread quickly, turning small vaccination gaps into wider outbreaks.

The key mechanism is airborne transmission. An infected person can release virus particles while breathing, coughing or sneezing, allowing nearby unvaccinated people to become infected. Children who have missed one or both vaccine doses lack the protection needed to interrupt transmission. This is why coverage must remain very high across communities, not just among some children.

Bangladesh’s outbreak illustrates the danger. Routine coverage fell to 90 per cent for the first dose and 86 per cent for the second in 2025. Since March 2026, more than 202,000 people were infected, showing how quickly transmission can intensify when protection declines.

The WHO says at least 95 per cent vaccination coverage is needed to prevent measles outbreaks. The reason is community protection: when nearly all children are vaccinated, measles has fewer opportunities to move from one person to another. This protects vaccinated children and reduces the chance that unvaccinated children will encounter the virus.

The threshold must apply broadly and consistently. Even when national coverage looks high, missed children can cluster in particular communities. Those pockets can sustain transmission. Protection also depends on children receiving the recommended doses, which is why the first-dose and second-dose figures both matter. Falling coverage increases the number of children who can become infected.

Bangladesh’s 2025 figures fell below the WHO benchmark. First-dose coverage was 90 per cent and second-dose coverage was 86 per cent, compared with 96 per cent and 93 per cent in 2024. The outbreak that began in March 2026 demonstrates the consequences of losing that protection.

Routine vaccination is the system that steadily protects children before disease spreads. In Bangladesh, that system weakened in 2025. First-dose coverage fell to 90 per cent, and second-dose coverage dropped to 86 per cent. Both were below the WHO’s 95 per cent benchmark. More children therefore remained unvaccinated or incompletely vaccinated.

Political turmoil made the problem worse after protests ended Sheikh Hasina’s 15-year rule. Health workers went on strike, vaccine orders were delayed and follow-up vaccinations normally linked to routine programmes were disrupted. These failures affected both vaccine availability and the ability to return for later doses. Children could consequently be missed even when programmes were planned.

Bangladesh had achieved stronger coverage in 2024, estimated at 96 per cent for the first dose and 93 per cent for the second. By 2026, the outbreak had infected more than 202,000 people. Emergency campaigns reached millions, but later evidence indicated that many children still lacked protection.

Bangladesh launched an emergency measles vaccination campaign as the outbreak worsened. The campaign reached almost 20 million children during April and May. Government officials said it covered every child aged six months to five years, the stated target group. Reaching that many children was a major response, but coverage claims were later questioned.

A separate routine health intervention in June covered the same age group but had a target list containing four million more children than the emergency campaign. That discrepancy suggested that the emergency campaign’s list was incomplete or that the underlying population data were unreliable. It raised doubts about how many eligible children had actually been located and vaccinated.

The concern continued after the campaign. August meeting minutes described the proportion of confirmed measles cases involving unvaccinated children as virtually unchanged. At the end of September, Bangladesh began another campaign for 3.4 million children it said had previously been missed.

Vaccination gaps give measles more opportunities to spread. As transmission intensifies, more children and families are exposed, health services face greater pressure and deaths can rise. Bangladesh’s outbreak killed 1,147 people and infected more than 202,000 from March 2026. The figures show that the consequences extend far beyond the children initially missed.

Responding after transmission has grown is difficult because health teams must find cases, trace affected communities and reach children who were overlooked. They must also organise additional vaccination campaigns while services are already dealing with illness. Bangladesh launched an emergency campaign for almost 20 million children, then planned another for 3.4 million children previously missed.

Mark Jit, a WHO vaccine adviser, called Bangladesh’s experience a warning to every country. He said preventing an outbreak through vaccination was easier, cheaper and safer than responding after transmission had intensified. Strong routine programmes therefore reduce both disease and the burden of emergency action.

Reliable health data show where children live, who has been vaccinated and where measles is spreading. Surveillance systems collect reports of suspected cases, while laboratories help confirm whether measles caused them. Together, these tools help officials find missed children, measure the outbreak accurately and direct vaccines and staff to the places at greatest risk.

Bangladesh’s emergency campaign exposed the danger of weak data. A June target list for the same age group contained four million more children than the emergency campaign’s list. That discrepancy raised questions about whether millions had been missed. In August, meeting minutes also reported that the share of confirmed cases involving unvaccinated children was virtually unchanged after the campaign.

Nigeria faced similar challenges. The NCDC called for harmonised surveillance and laboratory data, timely reporting and stronger follow-up with outbreak-affected states. By July, all 36 states and the FCT had reported suspected cases, but better data remained essential for planning supplementary immunisation and testing samples.