What will make vaccines work better in developing countries?

Story highlights

  • The rotavirus vaccine is worse at preventing severe diarrhea in developing countries than elsewhere
  • Researchers suspect that poor health and gut disease in young children could weaken their response to many oral vaccines
  • Anti-inflammatory drugs, probiotics and better sanitation could boost oral vaccines in countries that need them most

Dhaka, Bangladesh (CNN)For Mohommad Mustakim, the risk of diarrhea is everywhere. The 4-year-old and his family live in a crowded slum in Dhaka, Bangladesh, where open sewage and poor sanitation increase the spread of diarrhea-causing viruses and bacteria.

Rotavirus is the most common cause of severe diarrhea in young children worldwide, and in Bangladesh it kills nearly 6,000 children younger than 5 every year. In Pakistan, the infections kill an estimated 23,000 children a year. In India, the estimate is 78,000.
Although a rotavirus vaccine is one of the recommended childhood immunizations in countries like the United States, where the disease is responsible for only 20 to 60 deaths a year, it is not a routine immunization in many countries with a high burden of disease, including Bangladesh, Pakistan and India. Parents can pay for it themselves, but for many, it's too expensive.
    But Mohommad was supposed to have an advantage. When he was a baby, he was one of 350 infants who received the same highly effective rotavirus vaccine that's standard in the United States. Researchers followed the children for five years to see how well it protected them. Nasima Begum, Mohommad's mother, did not hesitate to take part in the study.
    "The vaccine is not available in our community and there is diarrhea in our community," she said.
    How did it do for Mohommad? Not very well.
    Before his first birthday, Mohommad had a rotavirus infection and suffered diarrhea at least 10 times in one day. He lost interest in eating and playing, Begum recalled. She took her baby back to the clinic where the study was being conducted and health workers there gave him oral rehydration solution, a sugary saltwater mix that has been a life-saving treatment for diarrhea in developing countries.
    Mohommad recovered, and by now, the worst is probably over, as dehydration and serious complications from rotavirus infections usually only occur in the first two years of life. But for his mother, the fear still lingers that he will develop diarrhea again. He had another bad rotavirus infection about a year ago and had to go to the clinic again.
    Open sewers in Bangladesh can spread viruses and bacteria that cause diarrhea.
    Mohommad's story could be a common one in Bangladesh, as well as many low-income countries in Africa and South America where the rotavirus vaccine is already included in the routine immunization schedule. While the rotavirus vaccine protects about 98% of children in developed countries such as the United States and Finland, a study found the same vaccine protected only 43% of Bangladeshi children from getting severe diarrhea from rotavirus in their first two years of life.
    India will soon add the vaccine to its routine immunization schedule, a move that is projected to save 27,000 of the 78,000 young lives that infections claim every a year. But that number could be higher if vaccine efficacy in India were greater than the 55% that studies have found.
    There is hope that improvements are on the way, but they will probably come in small steps rather than big strides forward, said Dr. William A. Petri, a professor at University of Virginia School of Medicine and lead researcher of the study in Dhaka in which Mohommad and his family are participating