Measles vaccination rolls on without an accurate count of eligible children, as paper coverage tops 120 percent

More than 21.7 million children have been vaccinated against measles in three phases to control the outbreak. The government says more children have been vaccinated than the target. Yet the measles infection is still not under control.

According to experts, judging a vaccination programme's success requires more than knowing how many children were vaccinated. The total number of children eligible for the vaccine must also be determined accurately. If the target is set too low, coverage can appear above 100 percent on paper while many children in fact remain outside vaccination.

Professor Dr Atikul Islam of the Department of Paediatric Infectious Diseases and Community Paediatrics at Bangladesh Shishu Hospital and Institute said measles vaccination coverage has still not reached 95 percent, although at least 95 percent of children must be vaccinated to control the infection. That level creates herd immunity, which also gives children who were not vaccinated considerable protection from infection. He said pockets or clusters of unvaccinated children in different areas are allowing the infection to spread.

Health Services Division Secretary Dr A N M Bazlur Rashid, however, said on Thursday that vaccination is continuing and that the country is close to building herd immunity, or a strong wall of disease resistance. He claimed measles has almost been brought under control and that vaccination is being ensured by going from house to house.

According to the Directorate General of Health Services, 1,299 people have died over the past eight months while under treatment with measles symptoms or confirmed measles. Since March 15, measles symptoms have been detected in 244,291 people and measles confirmed in 24,880. Of them, 218,000 were admitted to hospital and more than 209,000 were discharged.

The measles outbreak took a serious turn from March this year, and eight months on there is no sign of it coming under control. The national measles-rubella vaccination campaign that began on April 5 ended on May 20. Since then the health department has continued vaccinating children missed by the campaign alongside routine immunisation, but measles has not been controlled.

According to the Expanded Programme on Immunization (EPI) report of November 10, 18,446,122 children were vaccinated in the first phase of the measles-rubella campaign from April 5 to May 20, against a target of 18,015,064 children. Coverage in the first phase alone therefore stood at 102.2 percent.

A further 1,417,727 children were vaccinated from May 21 to September 25, and another 1,911,518 received the vaccine in the intensified campaign from September 26 to November 10. In total, 21,775,367 children have been vaccinated, and overall coverage from the start of the programme to November 10 stands at 120.9 percent.

A comparison with another campaign, however, raises questions about how the target was set. In the National Vitamin A Plus Campaign on June 28, the target for children aged six months to five years was set at 23.5 million—2.8 million aged 6 to 11 months and 20.6 million aged 12 to 59 months. By that count, the Vitamin A campaign's target was 5.5 million higher than the measles-rubella campaign's target.

A review article published this month in Emerging Infectious Diseases, a journal of the US Centers for Disease Control and Prevention (CDC), also raised concern about the method used to set targets in Bangladesh's vaccination programme. It said coverage shown above 100 percent can still hide vaccine shortfalls within a section of the population, and it also mentioned the possibility that vaccination figures are overstated.

Professor Dr Md Atikul Haque, dean of the Faculty of Preventive and Social Medicine at Bangladesh Medical University, said measles is highly contagious and there is no alternative to mass vaccination to stop its spread. For some other infectious diseases, vaccinating a large share of the population can indirectly protect the rest, but building such group protection is difficult for measles. At least 95 percent or more of children must therefore be brought under vaccination.

Public health experts say major disruption to the routine immunisation programme meant many children did not receive vaccines on schedule. Alongside special campaigns, they say routine vaccination must be strengthened and children who were missed must be identified and brought under vaccination to control the infection.

By division, the highest number of deaths with measles symptoms since March 15 this year—534—has been in Dhaka Division, followed by 210 in Sylhet, 120 in Chattogram, 93 in Rajshahi, 92 in Mymensingh, 70 in Barisal, 57 in Khulna and 18 in Rangpur. In the last 24 hours, five more people died with measles symptoms—three in Chattogram and one each in Dhaka and Sylhet, all under treatment; no death from confirmed measles was recorded that day.