Severe Measles Outbreak Reported in Bangladesh

2026-05-06 197

According to data released by the government of Bangladesh on April 29, a severe measles outbreak has been ongoing since mid-March, resulting in 227 child fatalities and approximately 35,000 suspected infections. The majority of cases have occurred in children aged 6 months to 5 years.

This outbreak is considered one of the most severe measles epidemics in the country in recent decades. Data cited from the World Health Organization indicate that between March 15 and April 14 alone, more than 19,000 suspected cases were reported, with nearly 3,000 laboratory-confirmed infections.

Declining vaccination coverage in recent years has been identified as a major contributing factor to the rapid spread of the outbreak, particularly in remote and underserved regions where access to healthcare remains limited.

Virological Characteristics and Genome Organization

Measles is caused by the Measles virus, a highly contagious pathogen belonging to the Paramyxoviridae family, genus Morbillivirus. It is an enveloped, non-segmented, single-stranded negative-sense RNA virus with a genome of approximately 16 kb.

The viral genome encodes six structural proteins: nucleoprotein (N), phosphoprotein (P), matrix protein (M), fusion protein (F), hemagglutinin protein (H), and large polymerase protein (L), as well as two non-structural proteins, V and C.

The hemagglutinin (H) protein mediates viral attachment to host cell receptors, including SLAM (CD150) expressed on immune cells and nectin-4 on epithelial cells. These receptor interactions determine viral tropism and systemic dissemination. Neutralizing IgG antibodies targeting the H protein are the primary mediators of long-term protective immunity.

The fusion (F) protein facilitates membrane fusion between the viral envelope and host cell membrane, enabling viral entry and subsequent replication within the cytoplasm.

Schematic representation of measles virus(Viruses. 2016 Oct 22;8(10):294.)

Transmission Mechanisms

Measles is among the most transmissible infectious diseases known, with a basic reproduction number (R₀) typically ranging from 9 to 18---significantly higher than that of SARS-CoV-2 or seasonal influenza viruses.

Transmission occurs primarily through respiratory droplets and aerosolized particles expelled when infected individuals cough or sneeze. The virus can remain infectious in the air or on surfaces for up to two hours, contributing to its high transmission efficiency.

Following inhalation, the virus initially infects respiratory immune cells, spreads systemically via lymphatic and hematogenous routes, and ultimately replicates in respiratory epithelial cells through nectin-4--mediated entry. Viral shedding from the respiratory tract enables further transmission.

Individuals are highly contagious from several days before to several days after rash onset, facilitating rapid and large-scale outbreaks, particularly in populations with insufficient vaccination coverage.

Measles epidemiology (A), transmission (B), disease course (C), and complications (D) (Nat Rev Dis Primers. 2016 Jul 14:2:16049.)

Pathogenesis and Clinical Manifestations

Measles infection typically presents as an acute febrile illness characterized by a prodromal phase followed by a generalized maculopapular rash. Early symptoms include high fever, cough, coryza, and conjunctivitis.

Beyond acute symptoms, measles virus induces a state of transient but profound immune suppression, increasing susceptibility to secondary infections. Severe complications may include pneumonia, diarrhea, encephalitis, and, in rare cases, Subacute sclerosing panencephalitis, a fatal progressive neurological disorder.

Diagnosis is based on clinical presentation in combination with laboratory confirmation, including measles-specific IgM antibody detection and/or viral RNA testing.

Measles symptoms (JAMA dermatology. 2019;155(12):1436.)

Prevention Strategies and Current Therapeutic Landscape

There is currently no specific antiviral therapy for measles, and clinical management remains largely supportive.

Vaccination is the most effective strategy for prevention. Live attenuated measles-containing vaccines (MCVs), including MMR (measles, mumps, rubella) and MMRV formulations, provide up to ~97% protection after two doses.

Despite the availability of highly effective vaccines, global coverage remains below the ~95% threshold required for herd immunity. The UNICEF and WHO have emphasized that declining immunization rates---driven by healthcare disruption, vaccine hesitancy, and access inequities---have contributed to the resurgence of measles worldwide.

In response to the current outbreak, Bangladesh has launched a nationwide vaccination campaign targeting approximately 18 million children, although the impact of these efforts will take time to become evident.

Measles vaccination (JAMA Pediatrics. 2018;172(9):896)

Summary

Measles remains a major global public health challenge despite the availability of safe and effective vaccines. Each year, tens of thousands of deaths---primarily among unvaccinated children under five---are attributed to measles infection.

Recent outbreaks highlight the critical importance of maintaining high vaccination coverage and strengthening healthcare infrastructure, particularly in vulnerable and hard-to-reach populations.

In parallel, ongoing research efforts are focused on advancing next-generation vaccine platforms (including mRNA and microarray patch delivery systems), antiviral drug discovery, and genomic surveillance strategies to better understand transmission dynamics and support long-term eradication goals.

Recombinant Protein

Antibody