Hookworm Vaccine Candidate Found Safe in Small Study

Attenuated L3 vaccine produced lower fecal hookworm DNA intensity in the study participants

child with barefeet

The findings from a vaccine study against hookworm were reported ‘mostly safe and well-tolerated’ at the annual meeting of the American Society of Tropical Medicine & Hygiene.

The results of a human challenge study with 15 patients were presented by Paul Chapman, M.D., of Queensland Institute of Medical Research-Berghofer in Australia, during session #92 on November 22, 2019.

This was a phase 1b clinical trial using an attenuated L3 vaccine delivered via dermal application to healthy human volunteers. 

Dr. Chapman’s study found ‘vaccinated participants had lower fecal hookworm DNA intensity and recovery of significantly fewer larvae, which are suggestive of a protective effect of this vaccine candidate.

In this limited study, vaccinated subjects had more robust dermal reactions and peripheral eosinophilia than control subjects, which is consistent with immune sensitization following vaccination.

‘Sensitization to larvae" occurred after repeated vaccination.

Furthermore, these subjects had significantly fewer larvae recovered per gram of cultured feces from vaccinated than control subjects (0.78 vs 10.16). 

And, the vaccinated subjects had lower fecal hookworm DNA intensity than control groups (cycle time 18.67 vs 16.63).

This is important news since an estimated 576-740 million people in the world are infected with hookworm, says the US Centers for Disease Control and Prevention (CDC).

In 1910, an estimated 40 percent of the population of the southern USA was infected with hookworm.

But, improvements in living conditions have greatly reduced hookworm infections. Hookworm, Ascaris, and whipworm are known as soil-transmitted helminths (parasitic worms).

Hookworm is an intestinal parasite of humans. The larvae and adult worms live in the small intestine which can cause intestinal disease.

Hookworm larvae live in soil and typically enter humans through the soles of their feet.  The larvae flow through the bloodstream and into a carrier’s lungs and throat before latching on to the small intestine. 

Hookworm eggs are expelled through the stool of a carrier, re-contaminating the soil and beginning the process anew.

Most people infected with hookworms have no symptoms. Some have gastrointestinal symptoms, especially persons who are infected for the first time.

Children are at greatest risk for experiencing severe growth, developmental and cognitive impairments as a result of hookworm-induced anemia, and they suffer the greatest morbidity compared to any other age group. 

The most serious effects of hookworm infection are blood loss leading to anemia, in addition to protein loss. Hookworm infections are treatable with anthelminthic medication prescribed by your healthcare provider.

This medication, such as albendazole and mebendazole, are the drugs of choice for the treatment of hookworm infections. The recommended medications are effective and appear to have few side effects. 

Iron supplements may also be prescribed by a healthcare provider if the infected person has anemia, says the CDC.

Dr. Chapman did not disclose any relevant industry relationships.

Hookworm vaccine news published by Precision Vaccinations