Measles vaccine not working effectively

A study has found that 27 per cent of children did not develop immunity (antibodies) against measles even after receiving the vaccine. This lack of immunity was more common among children aged 9 to 14 months.

Public health experts say the measles vaccine is not working effectively enough and that the government needs to rethink its approach to vaccination and the immunisation system.

The researchers involved said this was the first study of its kind to assess measles immunity among children under five in Bangladesh following the national measles-rubella vaccination campaign.

Twelve researchers and officials from the Directorate General of Health Services (DGHS), the Directorate General of Drug Administration (DGDA), the Institute of Epidemiology, Disease Control and Research (IEDCR), the Institute of Public Health, the Eastern Mediterranean Public Health Network and Dhaka Homoeopathic Medical College conducted the study. The IEDCR led the research. Prothom Alo obtained a summary of the findings from a source familiar with the study.

Following a measles outbreak in March this year, the health authorities launched a nationwide measles-rubella vaccination campaign on 20 April. The authorities decided to vaccinate all children aged between six months and five years.

The campaign ended on 20 May. Before the campaign, senior health officials had said in April that infections would come under control within three to four weeks of its conclusion. However, measles transmission has continued even five months after the campaign ended.

Against this backdrop, people have raised questions about how effectively the measles vaccine develops immunity in children and whether the vaccine is working properly, given that infections remain uncontrolled. Public health experts have also repeatedly called for a study to assess the vaccine’s effectiveness.

The IEDCR-led study took place in September this year, following the conclusion of the national measles-rubella vaccination campaign. Researchers included 309 children from six suburban and rural areas across Dhaka, Mymensingh and Munshiganj districts.

The children were aged between 9 and 59 months. Researchers verified their vaccination status by checking vaccination cards and speaking to their guardians. They tested blood samples from the children at the IEDCR laboratory.

The researchers found that 203 of the 309 children, or 65.7 per cent, had developed measles antibodies. Another 21 children, or 6.8 per cent, had antibody levels within the borderline range.

A scientist from a government institution in the health sector, who spoke to Prothom Alo on condition of anonymity, said, “We cannot say that these 21 children have developed antibodies, nor can we say that they have not.”

The study also found that 85 of the 309 children had developed no antibodies. In other words, 27.5 per cent of the children had not developed measles antibodies despite receiving the vaccine. The study found a higher prevalence of immunity among children aged 15 to 59 months than among those aged 9 to 14 months.

The researchers said that two or three doses of the vaccine produce stronger immunity than a single dose. However, the level of immunity among the children appears to be far below what is needed to stop measles transmission and prevent the disease from spreading.

Discussions with vaccine specialists and public health experts indicate that a vaccine’s effectiveness is partly related to a child’s age. If a child receives the vaccine at six months, 50 out of every 100 children will develop immunity.

At nine months, 85 out of every 100 children will develop immunity. If children receive the vaccine at 12 months, 90 per cent will develop immunity.

However, the IEDCR-led study found a much lower proportion of children who had developed immunity. Why did this happen?

Sources familiar with vaccination said that all vaccines used under the Expanded Programme on Immunisation (EPI) have approval from the World Health Organization (WHO).

However, authorities do not test the quality of these vaccines, as no system exists for such testing. They simply assume that the vaccines meet the required quality standards.

Vaccine specialist Tajul A Bari told Prothom Alo, “Several factors can impair or reduce a vaccine’s effectiveness. Vaccines must be stored and transported at specific temperatures. This is a lengthy process, and temperatures may fluctuate at any stage. Such fluctuations can compromise the quality of the vaccine.”

Tajul A Bari added that vaccines may be less effective in children suffering from severe malnutrition. By contrast, the measles vaccine works better in children who receive breast milk. He said, “It is essential to investigate the exact reasons why the vaccine is not working effectively.”

A joint independent review team comprising 70 local and international experts outlined the causes of the measles outbreak in Bangladesh at an event held at the Sonargaon Hotel in the capital on 14 October.

The team said structural weaknesses in the EPI leave around 20 per cent of children without routine vaccinations every year.

At the event, Health Minister Sardar Md Sakhawat Husain said that authorities should not take a complacent approach to vaccines. Children must receive vaccines of assured quality.

Vaccines travel through several stages, from production to airports and other points along the supply chain, before finally reaching children. He stressed the need to ensure that vaccines retain their effectiveness throughout this process. He also sought cooperation from the World Health Organization, UNICEF, Gavi and other organisations represented at the event.

The IEDCR study has now found that 27 per cent of children failed to develop immunity despite receiving the measles vaccine. This means that a large number of children remain at risk of contracting measles. As these children grow older, they may pass beyond the age covered by the vaccination programme.

Health Minister Sardar Md Sakhawat Hossain told Prothom Alo on Monday, “There is no reason to question the quality of the vaccine, as many countries are using it.”

Commenting on the IEDCR-led study, he said, “This is a very small study with a limited sample size. We should not draw any definitive conclusions from its findings. A larger study is needed.”

SMA Shafi, director of the Institute of Public Health, said researchers were conducting a more extensive study to assess and understand the situation. He told Prothom Alo that the study involved samples from 3,000 children, with researchers collecting samples from 100 children in each of 30 upazilas. They will publish the findings in the last week of November.

According to a press release issued yesterday, Monday, by the Directorate General of Health Services’ Coordination and Control Centre, 1,388 people across the country sought hospital treatment for measles symptoms in the preceding 24 hours. Six people died with measles symptoms during the same period.

This year, 222,552 people have sought treatment for measles symptoms at public and private hospitals across the country. Measles has claimed 1,233 lives this year. Of these, 1,129 people died with measles symptoms, while authorities confirmed 104 deaths from measles.

Professor Be-Nazir Ahmed, a former director of the disease control branch of the government, said vaccination coverage must exceed 95 per cent under the current circumstances.

He told Prothom Alo, “We can see that the measles vaccine is not working effectively enough. We must also expand the eligible age range for vaccination and bring children over five years old under the programme. Eventually, we should extend it to people up to 18 years of age. We must ensure a national vaccination campaign every four years. Bangladesh will not be able to overcome this serious measles situation without a comprehensive plan.”