Immunization, Vaccines and Biologicals

Soil-transmitted helminths

It is estimated that two billion people worldwide are affected by the burden of disease associated with helminth (parasitic worm) infections. Those most at risk and who would benefit from preventive intervention are preschool children (2-5 years of age), school-age children, and women of childbearing age (including pregnant women in the second and third trimesters and breastfeeding women).

Helminth infections of heavy intensity impair physical growth and cognitive development and are a cause of micronutrient deficiencies including iron anaemia, leading to poor school performance and absenteeism in children, reduced work productivity in adults and adverse pregnancy outcomes.


WHO recommends periodic treatment with anthelminthics (deworming) medicines without individual diagnosis to all at-risk children living in endemic areas. Anthelminthics are safe and their administration is simple enough that it can be conducted by non-medical staff such as teachers or trained volunteers. The frequency of treatment (once or twice per year) is determined by the prevalence and intensity of infection in the area.

Opportunities to link deworming with immunization

The simplicity with which anthelminthic treatment can be delivered makes deworming an easy intervention to co-administer with immunization and many countries have included deworming with their measles or polio vaccination campaigns. In 2012, over 78 million preschool children received deworming treatment through immunization campaigns, child health days or vitamin A distribution, corresponding to 24.7% percent coverage of the children in need of treatment.

Articles on integrating deworming and immunization

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