"Bangladesh Measles Outbreak Exposes Vaccine Coverage Gaps and Governance Failures"
Herd immunity
indirect protection of unvaccinated individuals when enough of the population is immune.
Herd immunity threshold
minimum vaccination coverage needed to stop disease transmission; 95% for measles.
Measles is a highly contagious airborne viral disease caused by the Measles morbillivirus, belonging to the Paramyxoviridae family. It spreads through respiratory droplets and can remain infectious in the air for up to two hours after an infected person leaves a room. The disease causes fever, cough, runny nose, and a characteristic red rash, and can lead to severe complications including pneumonia, diarrhoea, and encephalitis (brain swelling), particularly in young children and immunocompromised individuals.
Unlike smallpox, the only human disease to have been globally eradicated, declared so in 1980, measles has not been eradicated. It remains endemic in many parts of the world. Diseases such as diphtheria, whooping cough (pertussis), and tetanus, which Bangladesh's vaccination programme historically controlled alongside measles, are similarly not eradicated: they resurge whenever vaccination coverage lapses. This is a critical distinction. Eradication means zero natural transmission worldwide; control means keeping case numbers low through sustained immunisation. Measles sits firmly in the second category, which means any gap in vaccination immediately creates conditions for an outbreak.
The WHO estimates that two doses of the measles-containing vaccine provide approximately 97% protection. However, because measles is so contagious, at least 95% of the population must be vaccinated to achieve herd immunity, the threshold at which the disease cannot sustain transmission even among unvaccinated individuals. This 95% threshold is among the highest of any vaccine-preventable disease, reflecting measles's exceptionally high basic reproduction number (R0 of 12–18). Falling below this threshold, even briefly, creates a susceptible population large enough to sustain an outbreak.
Vaccine-preventable disease outbreaks follow a predictable pattern: coverage gaps accumulate silently over several years, then a trigger event, a political disruption, a pandemic, a supply failure, causes a visible surge in cases. The Bangladesh outbreak illustrates this mechanism clearly. Between 2021 and 2025, routine immunisation was disrupted first by the COVID-19 pandemic, which caused families to avoid health facilities, and then by political instability in 2024, which interrupted a scheduled four-yearly vaccination campaign. The result was a growing cohort of unvaccinated children aged four to five years, precisely the age group most vulnerable to severe measles.
Herd immunity is not just about protecting vaccinated individuals. It also protects those who cannot be vaccinated: infants under six months (too young for the measles vaccine), immunocompromised patients, and pregnant women. When coverage falls below 95%, these groups lose their indirect protection. …
Consider the following diseases:
1.Diphtheria
2.Chickenpox
3.Smallpox
Which of the above diseases has/have been eradicated in India?
Consider the following statements regarding measles and vaccination:
1.Two doses of the measles vaccine provide approximately 97% protection against the disease.
2.The herd immunity threshold for measles is 95% of the population, higher than for most other vaccine-preventable diseases.
3.Measles has been globally eradicated, similar to smallpox.
4.Infants under six months of age are too young to receive the standard measles vaccine.
How many of the above statements are correct?
Which of the following diseases has/have been globally eradicated?
1.Smallpox
2.Measles
3.Poliomyelitis
4.Rinderpest (cattle plague)
Select the correct answer using the codes below:
Match the following vaccine-related institutions/programmes with their descriptions:
List I (Institution/Programme) — List II (Description)
A.Gavi Vaccine Alliance — 1. India's programme to reach unvaccinated children under UIP, launched 2014
B.Mission Indradhanush — 2. Global partnership supporting vaccine access in LMICs through co-financing, est. 2000
C.Universal Immunisation Programme — 3. WHO-initiated global framework for routine childhood vaccination, launched 1974
D.Expanded Programme on Immunisation — 4. India's national routine immunisation programme, launched 1985
Consider the following statements about the measles vaccine and disease control:
1.The measles vaccine is recommended for infants from six months of age in outbreak settings, though the standard schedule begins later.
2.Measles is transmitted through direct contact with infected surfaces, not through the air.
3.The basic reproduction number (R0) of measles is among the highest of any known infectious disease, estimated at 12–18.
Which of the above statements is/are correct?
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