Published: 12:11 AM, 13 October 2026
Measles in Children Under Six Months: A Warning Signal for Bangladesh
Nazmun Nahar Nipa
The first dose of the measles vaccine is typically administered at 9 months of age. Recently, however, a significant proportion of children affected by measles fall under the age of six months in Bangladesh. One of the fundamental principles of medical science is that the antibodies of the mother protect the infant from measles for at least the first six months of life. However, the recent outbreak has demonstrated the limitations of this assumption in practice. Medically, this is an outbreak of disease and a significant warning signal for maternal antibodies, immunization programs and the country's public health system.
The age distribution of patients infected with measles in Bangladesh during the 2026 outbreak is a matter of concern for epidemiologists. During 15 March – 14 April 2026, WHO recorded the number of suspected cases of measles – 19,161 and laboratory-confirmed cases – 2,973. Thus, 58 of Bangladesh's 64 districts (91%) were affected by the disease. However, the most surprising fact is that 81% of Bangladeshi patients were children under five, with 34% of the total number of infected being fewer than nine months. In other words, most of the infected population was under the age eligible for routine vaccination.
Measles Vaccine Doses and Schedule
First dose: When the child reaches nine months of age (MR or measles-rubella vaccine).
Second dose: When the child reaches 15 months of age (second dose of the measles vaccine).
In this situation, the government, WHO, UNICEF, and Gavi have launched an emergency measles-rubella vaccination campaign for children aged 6–59 months.
Are Maternal Antibodies Failing to Protect Infants Against Measles for the First Six Months?
No. But this protection is not complete or equal for all infants.
During the later stages of pregnancy, mothers transfer IgG antibodies to the fetus through the placenta. These antibodies provide partial protection against measles and several other infections during the first few months after birth.
However, one thing to note is that this protection, on the contrary, gradually decreases. It does not disappear suddenly on a specific day. In some infants, antibody levels may drop substantially by four months of age, while others may retain some protection until six to eight months of age.
In other words, the assumption that infants receive assured protection against measles for the first six months of life has no scientific basis.
What Are the Reasons Behind This?
1. Vaccine-Induced Immunity Versus Naturally Acquired Immunity
In the past, most mothers acquired immunity by acquiring natural infection with measles. Nowadays, most mothers acquire protection through vaccination.
Several international studies have found that antibodies transferred to infants by mothers with vaccine-induced immunity may decline more rapidly in many cases than antibodies transferred by mothers who acquired immunity through natural infection.
2. Premature Birth
A very important factor. The maximum amount of maternal antibodies enters the baby's body during the last three months of pregnancy.
As a result, babies born prematurely have comparatively less maternal antibodies and may become vulnerable to infections faster.
3. Weakening of Herd Immunity
Measles is one of the most contagious diseases in the world. At least 95% vaccination coverage is required for this disease to be controlled effectively.
WHO has reported that disruptions to routine immunization during the COVID-19 pandemic, vaccine supply shortages, and delays in supplementary immunization activities have created an immunity gap in Bangladesh.
4. Increased Exposure to the Virus
During a major outbreak, if a family member becomes infected, then the likelihood of the infant becoming infected also rises.
If maternal antibody levels are low, then even infants younger than six months can become infected.
5. Malnutrition
Particularly important in the context of Bangladesh.
Vitamin A deficiency, in particular, weakens the immune system and increases the risk of complications and death from measles. For this reason, WHO recommends that vitamin A be supplemented for children affected by measles.
Are Infants Under Six Months Becoming Infected Because of a New Measles Virus Variant?
No. Until now, neither WHO nor the Directorate General of Health Services (DGHS) of Bangladesh has stated that the 2026 outbreak was caused by a new measles virus variant.
According to the information currently available, the main reasons are:
• Low vaccination coverage
• Immunity gaps
• Widespread transmission
• An increase in the number of vulnerable children
Is This Type of Infection Occurring for the First Time in 2026?
No. Measles infection in infants younger than six months is not a new phenomenon.
However, the number of affected infants in this age group has drawn particular attention in 2026.
Approximately 18% of measles-infected children admitted to a children's hospital in Dhaka in 2026 were younger than six months.
International research also shows a similar trend. Several studies conducted in the Netherlands, Canada, the United States, the United Kingdom, and China have shown that, over the past two decades, the duration of maternal antibody protection in infants has declined and many infants are losing their protection between four and six months of age.
Why Is Routine Measles Vaccination Not Given Before Nine Months of Age?
Many people ask: if young infants are becoming infected, why isn't the vaccine given at an earlier age?
The answer is that at a very young age, antibodies received from the mother can sometimes neutralize the vaccine virus. As a result, the vaccine may fail to produce the expected immune response.
For this reason, the first dose is administered at nine months of age under the routine immunization programme.
What Should Bangladesh Do?
The 2026 measles outbreak clearly reminds us that simply developing a vaccine is not enough to control a disease.
It is necessary to ensure complete coverage under the National Expanded Programme on Immunization (EPI), promptly identify children who have missed vaccination and bring them under the immunization programme, ensure an adequate and uninterrupted vaccine supply, strengthen age-specific surveillance, and initiate research on the gradual decline of maternal antibodies in the context of Bangladesh.
When a child becomes infected with measles before even reaching the recommended age for routine vaccination, it is not just a medical issue but also a test of the effectiveness of our public health system. If we do not take this warning sign seriously today, the consequences may be more severe in the future.
In this context, microbiologists also have an important role to play. Microbiologists can contribute significantly through effective laboratory surveillance of the measles virus, research on viral genotypes and transmission patterns, evaluation of maternal antibody persistence and vaccine effectiveness, and the promotion of public awareness through evidence-based scientific information.
A coordinated approach to research, surveillance, and public health initiatives can take Bangladesh one step closer to measles control and elimination in the future.
Nazmun Nahar Nipa belongs
to Department of Microbiology, Jahangirnagar University.
