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Disease and treatment

Childhood vaccination provides a growth bonus

The early vaccination of children in low-income countries has proved to be a really good idea. Since the 1970s, when mass vaccination campaigns began in Africa, the number of deaths caused by measles has declined by 40%. Danish researchers – led by researchers from Denmark’s BANDIM Health Project – have been in the forefront and can now report a somewhat surprising bonus to the previously positive statistics: vaccinated children grow more rapidly if they are vaccinated earlier.

The research is based on data from 2003–2007 from Guinea-Bissau, which was and is one of the countries most severely affected by measles. In the 1970s, 5 of 10,000 children died from the disease. Today, this number has declined by 20%, but there is still a long road ahead in combating measles because measles causes more than 10% of all deaths among children younger than 5 years old. The efforts to vaccinate even more children are therefore still paramount.

One trial attempted to move vaccination from 9 to 4.5 months after birth. This provided a surprising extra bonus. The vaccinated children avoided becoming ill with measles and improved their general nutritional status. Researchers measured this using the circumference of a child’s mid-upper arm, and the children vaccinated earlier were nearly 10% larger after 24 months. The greatest effect was among girls, whose mid-upper arms were 12% larger.

The researchers interpreted the effect as confirming what they had previously suspected: that measles vaccination has beneficial non-specific effects on other infectious diseases. The vaccination has therefore been attributed to a higher proportion of the overall effects of the efforts to prevent child mortality in low-income countries.

The results are unique because the researchers examined and proved for the first time that vaccination positively affects children’s nutritional status. Previously, the view was that vaccination only provided immunity against a specific disease. The new results indicate a generally lower mortality rate and fewer hospitalizations following vaccination. However, further research is required to understand these effects sufficiently.

The heart of the Bandim Health Project is a thorough research and registration process, which has previously led to several notable discoveries. One of the most important results was that a new measles vaccine introduced in low-income countries was associated with a large increase in mortality, especially among girls. This discovery led to the vaccine being withdrawn in 1992 and replaced by a new one. If this had not happened, it would have led to at least 500,000 more deaths among girls in Africa.

The effect of early measles vaccination at 4.5 months of age on growth at 9 and 24 months of age in a randomized trial in Guinea-Bissau” has been published in BMC Pediatrics. In 2014, the Novo Nordisk Foundation awarded a grant for the project Smarter Use of Vaccines: Improving Health in Both Man and Livestock through a Better Understanding of Non-specific Effects of Vaccines. The study is part of the Bandim Health Project to which the Foundation has awarded grants of more than DKK 14 million.

Christine Benn
Head of Department, Professor in Global Health
Christine Stabell Benn is responsible for planning, executing and publishing epidemiological and immunological studies of health interventions in Guinea-Bissau and Denmark. She supervises a number of pre- and postgraduate/PhD students. Christine Stabell Benn has formulated the hypothesis that vitamin A supplementation and routine child vaccinations interact with consequences for mortality. Both types of interventions seem to have non-specific effects on the immune system, affecting its ability to handle infectious diseases. The effects are different in boys and girls.