The findings were particularly concerning among children aged nine to 14 months, who were less likely to have developed antibodies than older children. Public health experts have called for a thorough assessment of vaccine effectiveness and the systems responsible for storing, transporting and administering vaccines.
However, the findings do not conclusively establish that the measles vaccine itself is ineffective. Health officials have stressed that the study involved a relatively small sample and that larger investigations are needed to determine why some children did not develop detectable antibodies.
The research was conducted after a nationwide measles-rubella vaccination campaign earlier this year. Despite the campaign, infections have continued, intensifying concerns about gaps in routine immunisation and the country’s ability to contain the outbreak.
Study Examines Antibody Levels in 309 Children
Led by the Institute of Epidemiology, Disease Control and Research (IEDCR), the study was conducted in September following the national measles-rubella vaccination campaign.
Twelve researchers and officials from several institutions participated, including the Directorate General of Health Services, the Directorate General of Drug Administration, IEDCR, the Institute of Public Health, the Eastern Mediterranean Public Health Network and Dhaka Homeopathic Medical College.
The researchers examined 309 children aged between nine and 59 months from six suburban and rural areas in Dhaka, Mymensingh and Munshiganj districts.
The children’s vaccination histories were verified by checking vaccination cards and speaking to their parents or guardians. Blood samples were subsequently tested at the IEDCR laboratory to determine whether measles antibodies were present.
The results showed that 203 children, or 65.7 per cent of those tested, had detectable antibodies against measles. Another 21 children, representing 6.8 per cent, had antibody levels in a borderline range, making it difficult to establish whether they had developed sufficient immunity.
The remaining 85 children, equivalent to 27.5 per cent of the sample, had no detectable measles antibodies.
A scientist from a government health-sector institution, speaking on condition of anonymity, said the results for children with borderline antibody levels did not establish conclusively whether they had developed immunity.
The findings have raised concerns because measles is highly contagious and can cause serious illness, particularly among young children. However, the absence of detectable antibodies in a blood test does not, by itself, establish every aspect of a child’s immune protection. Further assessment is needed to understand the clinical significance of the results.
Younger Children Show Lower Levels of Immunity
The study found that children aged 15 to 59 months were more likely to have developed measles antibodies than those aged nine to 14 months.
Vaccine specialists say a child’s age at vaccination can influence the immune response. Estimates cited by specialists suggest that vaccination at six months may produce an immune response in around 50 per cent of children. The proportion rises to approximately 85 per cent when vaccination takes place at nine months and around 90 per cent at 12 months.
These are general estimates rather than results from the IEDCR study itself. The differences underline the importance of considering children’s ages and vaccination histories when assessing immunity.
Researchers also noted that two or three doses of a vaccine can produce a stronger immune response than a single dose in many children. Maintaining high levels of immunity across the population is particularly important for measles because the virus spreads rapidly among susceptible people.
The comparatively low proportion of children with detectable antibodies in the study has therefore prompted questions about whether existing immunisation arrangements are providing sufficient protection.
Public health experts argue that vaccination coverage alone is not enough to assess the success of an immunisation programme. Authorities must also consider whether children receive the appropriate doses at the right time and whether the vaccines retain their effectiveness throughout the distribution process.
Nevertheless, the study does not identify a definitive cause for the antibody results. Researchers will need to examine several possible explanations before drawing conclusions about the performance of the vaccination programme.
Vaccine Storage and Transport Under Scrutiny
Vaccine specialist Tajul A Bari has identified temperature control during storage and transportation as one possible factor affecting vaccine effectiveness.
Vaccines must be maintained within specified temperature ranges throughout the supply chain, from production and international transport to storage facilities and local vaccination centres. A failure to maintain the required conditions at any stage can compromise vaccine quality.
Bari said vaccine effectiveness could be reduced for several reasons and stressed the need to investigate why some vaccinated children had not developed detectable antibodies.
Severe malnutrition may also affect a child’s immune response to vaccination. Bari said malnourished children could respond less effectively to vaccines, while breastfeeding was associated with a stronger response to measles vaccination.
Experts say these possibilities should be investigated alongside other factors, including the timing and number of doses received, individual differences in immune responses and the methods used to measure antibody levels.
The vaccines used under Bangladesh’s Expanded Programme on Immunisation (EPI) are authorised by the World Health Organisation. However, the use of an authorised vaccine does not automatically establish that its quality has been maintained at every stage before administration.
The findings have consequently renewed calls for stronger monitoring of vaccine quality, improved oversight of storage and transportation, and more systematic assessments of immunisation outcomes.
Routine Immunisation Gaps May Be Contributing to the Problem
The antibody study comes amid wider concerns about weaknesses in Bangladesh’s routine immunisation system.
On 14 October, a joint independent review team comprising 70 local and international experts presented its assessment of the factors contributing to the measles outbreak at an event in Dhaka.
The team identified structural weaknesses in the EPI and said around 20 per cent of children miss routine vaccinations each year.
Children who miss scheduled doses may remain susceptible to measles and other vaccine-preventable diseases. When a substantial proportion of children lack immunity, the virus can spread more easily, particularly in communities where vaccination coverage is uneven.
The challenge is therefore not limited to organising emergency vaccination campaigns. Health authorities must also identify children who have missed routine doses, maintain accurate vaccination records and ensure that vaccines are stored and administered correctly.
At the October event, Health Minister Sardar Md Sakhawat Hossain said the country should not rely blindly on existing arrangements but must ensure that children receive vaccines of the required quality.
He emphasised that vaccines pass through several stages between production and administration, including transportation through airports and subsequent distribution. Their effectiveness must be preserved throughout the process.
The minister also sought support from international organisations, including the World Health Organisation, UNICEF and Gavi, to strengthen vaccination efforts.
Health Minister Calls for a Larger Study
Despite the concerns raised by the research, the health minister has rejected the suggestion that the findings provide sufficient grounds to question the quality of the vaccines being used.
Speaking to Prothom Alo on Monday, Sardar Md Sakhawat Hossain said the vaccines were used in many countries. He argued that the results of a small study should not be used to reach a definitive conclusion and called for a larger investigation.
His comments highlight the need to distinguish between the absence of detectable antibodies in a sample of children and evidence that a vaccine is generally ineffective.
A broader investigation would need to examine vaccination records, vaccine handling, children’s ages, laboratory findings and other factors that could influence immune responses.
A larger study is already under way, according to SM A Safi, director of the Institute of Public Health.
He said researchers were collecting samples from 3,000 children across 30 upazilas, with 100 children selected from each upazila. The results are expected to be published in the final week of November.
The larger investigation is expected to provide a more representative picture of measles immunity among children and help identify potential weaknesses in vaccination delivery.
Measles Cases and Deaths Continue to Rise
The concerns over childhood immunity come as Bangladesh continues to face a serious measles outbreak.
According to the latest bulletin from the Directorate General of Health Services’ Integrated Control Centre, 1,388 people sought hospital treatment with measles symptoms across the country in the preceding 24 hours. Six people with suspected measles died during the same period.
The bulletin reported that 222,552 people had sought treatment at public and private hospitals for measles symptoms since the beginning of the year.
It also recorded 1,233 deaths associated with the outbreak. Of these, 1,129 were deaths among people with suspected measles, while 104 were confirmed measles deaths.
These categories are distinct. Deaths among people with suspected measles are not necessarily confirmed as deaths caused by the virus, so the figures should be interpreted separately.
The scale of the outbreak nevertheless underlines the pressure on health services and the need to strengthen preventive measures.
Measles is a highly contagious viral disease that can cause serious complications, particularly in young children. These include pneumonia, severe diarrhoea and inflammation of the brain. Vaccination remains the principal means of preventing infection and reducing the risk of severe illness and death.
Experts Call for Coverage Above 95 Per Cent
Benazir Ahmed, a former director of the government’s disease control branch, has called for measles vaccination coverage to rise above 95 per cent as part of a broader strategy to control the outbreak.
He said the age range covered by vaccination campaigns should also be reconsidered so that children older than five who remain susceptible can be included. In the longer term, he suggested extending campaigns to people up to the age of 18, depending on the needs identified through public health assessments.
Ahmed also called for national vaccination campaigns to be organised every four years, arguing that a larger and more sustained strategy would be needed to bring the outbreak under control.
Public health experts say emergency campaigns alone cannot compensate for persistent weaknesses in routine immunisation. Consistent vaccination coverage, accurate records, reliable vaccine storage and follow-up for children who miss doses are all essential.
The latest findings have added urgency to calls for a comprehensive review of Bangladesh’s measles prevention strategy. Yet the study should be regarded as a warning that warrants further investigation, rather than definitive proof that the vaccine itself is failing.
The larger study involving 3,000 children is expected to provide additional evidence. In the meantime, health authorities face the twin challenges of controlling the current outbreak and ensuring that children receive effective protection through a reliable and well-monitored vaccination system.
