Gut damage culprit of vaccine failure, malnutrition

The world of vaccines was just thrown a curveball, when a team of researchers found that the gut could be playing a part in the vaccine failure and malnutrition.

It has been estimated that if every nutritional measure known to be helpful were applied to every child in the world, global malnutrition would be decreased by only a third. New research from the University of Virginia School of Medicine, the University of Vermont and the International Centre for Diarrhoeal Disease Research in Bangladesh sheds light on why.

Damage to the gut from infection explains why food alone is not a solution to malnutrition. To be effective, nutritional therapy will need to include measures to prevent or treat the damage to the gut of infants.

The researchers for the last four years have enrolled children at birth and their parents from an urban slum in Dhaka, Bangladesh. The children are visited in their homes twice a week, receive free medical care and are observed for the development of malnutrition. Malnutrition is measured by children becoming stunted or abnormally short for their age.

Despite vaccination, free medical care and nutritional counseling and care, stunting increased from 9.5 percent at enrollment to 27.6 percent at 1 year of age. This demonstrated what has long been known, that malnutrition is extraordinarily difficult to prevent or treat.

It was as fascinating as disturbing that nearly one in four children in the study developed malnutrition by their first birthday, said researcher Caitlin Naylor.

The researchers suspected that food was not being properly digested by the children who were becoming stunted.

Bill Petri added that they knew that the children's intestines were being repeatedly infected, on a near daily basis, in a situation completely different from infants in Charlottesville that rarely are infected and do not suffer from malnutrition. They decided to test to see if damage to their gut from infection was causing malnutrition.

The researchers in Bangladesh did the same tests on the Bengali children that are done in children in US suffering from inflammatory bowel disease. Nearly every child had abnormal results, indicating their guts were damaged.

The potentially life-saving rotavirus vaccines also are substantially less effective in these children that need the vaccines the most, researchers said.

One of the obstacles to the global campaign to eradicate polio has been the relative ineffectiveness of the oral vaccine in developing countries, sometimes necessitating upwards of 10 doses to be effective, they said.

"Since these two vaccines immunise the intestine, we tested if children with the worst gut damage also suffered from vaccine failure," said Petri. This was found to be the case, demonstrating that a damaged gut caused both malnutrition and oral vaccine failure.

The findings appear in the journal EBioMedicine.