Bill & Melinda Gates Foundation

A New Perspective on the War on Worms

September 01, 2015

There has been much debate over the last few weeks among Western scientists about the efficacy of school-based mass deworming programs. Notably missing from this debate have been the voices of people from countries where parasitic worms are prevalent.


Worm infections may not be a concern in high-income countries where sanitation infrastructure is well developed, but here in Kenya, like in many countries around the world, these parasites invade our children’s bodies and compromise children’s health and well-being. Globally, it is estimated that more than 870 million children worldwide are infected with soil-transmitted helminths and schistosomiasis, neglected tropical diseases that cause havoc on a child’s health.


As a scientist and a Kenyan, I have reviewed the evidence, and authored numerous studies that quantify the problem and that show how mass deworming lowers prevalence of STH and schistosomiasis. And I have visited hundreds of schools and spoken to thousands of Kenyan school children and members of the community.


I have studied and seen myself the negative effects chronic parasitic worm infections have on childhood development. Children with severe or recurring infections have impaired growth and cognitive development because the worms lodge in their bodies, stealing the nutrients a child is able to take in. Heavy infections can result in serious clinical disease. To combat infection and give our children a chance at good health, many countries, including Kenya, run school-based mass deworming programmes that have been shown to be a simple and cost-effective strategy to reduce the disease burden of parasitic worms in school-age children, the group at highest risk.


Safe, low-cost drugs are available to treat intestinal worm infections and are the standard of medical care. The World Health Organization (WHO) recommends periodic mass treatment in areas where worm infections are above certain thresholds. Some have challenged this WHO policy, accepting that those who are known to be infected should be treated, but questioning whether the existing evidence base is strong enough to support mass treatment.

Let me say unequivocally: Mass school-based deworming works. Just three years ago, Kenya launched a national deworming program. Prevalence of parasitic worms has been reduced from 35% to 17% and as low as 6% right after a deworming round. Our focus in the National Deworming Programme in Kenya is on the reduction of infection and possibly even elimination of the public health threat of worms.


What cannot be disputed is that in taking steps needed to achieve this reduction in children, their general health and nutritional status are immensely improved. Children who do not compete with parasitic worms for their food are more likely to participate in daily activities, including going to school.


We are closer than ever to eliminating the public health risk of parasitic worms in children. Let us not get distracted, from giving our children the very best chance in life to succeed. Until access to water and sanitation is widespread and reliable, we simply cannot deny them an intervention that works.


  • Tags
  • Share
blog comments powered by Disqus