The silent return of a killer: Bangladesh's measles crisis

For decades, Bangladesh was regarded as one of South Asia's public health success stories. Through an impressive national immunization programme, millions of children were protected from diseases that once claimed countless young lives. Once on the brink of elimination in Bangladesh, measles, one of the world's most contagious viral diseases has made a devastating comeback.

Bangladesh is now battling one of its largest measles outbreaks in decades. Since the outbreak began in March 2026, the Directorate General of Health Services (DGHS) has recorded more than 100,000 suspected measles cases, with over 10,000 laboratory-confirmed infections. The human cost has been devastating. By early July 2026, the country had reported 738 confirmed and suspected measles-related deaths, the overwhelming majority among children.

These are not merely statistics. Behind every number is a child who should have lived and a family whose future has changed forever.

The most painful aspect of this outbreak is that many of those dying are infants younger than nine months, children who are too young to receive Bangladesh's routine first dose of the measles-containing vaccine. These babies depend entirely on antibodies transferred from their mothers during pregnancy for protection. Yet many are becoming infected before they are old enough to be vaccinated.

Why is this happening?

The answer is complex, but it does not begin with the virus. It begins with the body's defense system, that we scientifically term as "immunity."

During the COVID-19 pandemic, routine childhood immunization programmes around the world were disrupted. Bangladesh, despite its historically strong Expanded Programme on Immunization (EPI), was not immune to these challenges. Thousands of children missed scheduled vaccinations, creating an "immunity gap" that quietly grew over several years. Once measles found these susceptible children, it spread with astonishing speed.

Unlike many infectious diseases, measles offers very little room for error. One infected child can infect 12 to 18 others in an unvaccinated population. To stop transmission, at least 95% of people must be immune. When vaccination coverage falls even slightly below that threshold, outbreaks become almost inevitable.

There is another, less recognized concern.

Today's mothers are increasingly protected against measles through vaccination rather than natural infection. This is a remarkable public health achievement, but studies suggest that vaccinated mothers may transfer lower levels of protective antibodies to their newborns than mothers who recovered from natural measles infection. Consequently, infants may lose maternal protection several months before they become eligible for routine vaccination, creating a dangerous window of vulnerability.

On the contrary, malnutrition compounds this risk. Children who are undernourished are far more likely to develop severe pneumonia, diarrhea, encephalitis, blindness, and other life-threatening complications following measles infection. In many low-income communities, poor nutrition and delayed access to healthcare create a perfect storm for severe disease.

The current outbreak should also remind us that measles is not simply "a childhood rash."

The virus attacks the immune system itself. After infection, it can erase parts of the body's immune memory, a phenomenon scientists call "immune amnesia." Children who recover from measles remain vulnerable to other infections for months or even years, making measles far more dangerous than many people realize.

As the outbreak has grown, another question has naturally emerged.

Has the virus itself changed?

At present, there is no evidence that Bangladesh is facing a vaccine-resistant strain of measles. Unlike influenza or SARS-CoV-2, the measles virus has only one serotype, and the current measles vaccine continues to provide excellent protection against all known circulating genotypes.

Nevertheless, this underscores the importance of continued scientific investigation.

Viruses continuously accumulate small genetic mutations as they spread. Most of these mutations have little or no effect on disease or vaccine protection, but genomic surveillance remains essential. Sequencing viruses from patients across Bangladesh can reveal whether the outbreak is being driven by a single lineage or multiple imported strains, identify transmission pathways, and help determine whether changes in viral genetics are associated with increased transmissibility or disease severity. While there is currently no evidence that a new strain is responsible for this outbreak, only systematic genomic surveillance can answer that question.

Bangladesh now has an opportunity to generate evidence that will guide public health policy for years to come. By combining epidemiological investigations with clinical studies, measurements of protective antibodies, vaccine effectiveness analyses, and whole-genome sequencing of circulating measles viruses, researchers can identify the factors driving this unprecedented outbreak and recommend targeted interventions.

In response to this growing public health concern, the Department of Microbiology, in collaboration with the Department of Community Medicine and Public Health at Ibrahim Medical College, has initiated a prospective cohort study under the supervision of Professor Md. Sharif Alam Jilani to investigate one of the most pressing questions raised by the current outbreak: Are Bangladeshi infants becoming susceptible to measles because maternally derived antibodies are declining too early, or because they receive insufficient protective antibodies from their mothers at birth?

The study will follow mother-infant pairs from delivery, measuring measles-specific maternal antibodies in newborns at birth and at regular intervals to determine how rapidly these protective antibodies wane during the first year of life. By identifying the period when infants become vulnerable to measles infection, the research aims to generate evidence on the duration of passive immunity in Bangladeshi children.

If the study confirms that Bangladeshi infants lose maternally derived measles antibodies well before the recommended vaccination age of nine months, it could have important implications for national immunization policy. The findings may support strategies such as administering an earlier measles vaccine dose during outbreaks or strengthening measles immunity among women before pregnancy. Further advanced research by examining maternal and infant genetic factors may be conducted to evaluate the influence of antibody transfer and persistence, as well as sequencing of circulating measles viruses may be utilized to monitor transmission patterns and viral evolution. Together, these findings could help policymakers develop evidence-based interventions to better protect infants from measles, including the Expanded Programme on Immunization (EPI) and the Directorate General of Health Services (DGHS), to evaluate whether the current timing of the first measles vaccine remains optimal or whether earlier vaccination, additional booster doses, or other targeted public health interventions should be considered to better protect infants during this vulnerable period.

Routine immunization must be strengthened, missed children must be identified and vaccinated, and outbreak response vaccination campaigns accelerated in high-risk areas. Parents must recognize that fever, cough, red eyes, and rash require prompt medical attention, not home remedies or over-the-counter medicines from local shops.

The resurgence of measles is not a failure of the vaccine. It is a warning about what happens when immunity gaps accumulate.

Bangladesh has defeated measles before. It has the scientific expertise, public health infrastructure, and dedicated healthcare workers needed to do so again. But success will require renewed commitment - from policymakers, healthcare professionals, researchers, and every parent who brings a child for vaccination.

The children dying today are not victims of an untreatable disease. They are victims of preventable gaps in protection. Closing those gaps is both our greatest challenge and our greatest responsibility.

Dr Saika Farook is an Assistant Professor Department of Microbiology Ibrahim Medical College