World-first live hookworm vaccine for humans could be the first step to eradication

The first ever live vaccine against human hookworm has been developed by researcher and infectious disease clinician  Dr Paul Chapman, a member of the Immunology Department at QIMR Berghofer, and tested in a Phase I clinical trial.

Hookworms cause a parasitic disease, primarily in developing countries, that seriously reduces quality of life.

This vaccine could be the first step to eradicate human hookworm infection.

Dr Chapman said hookworm was a global problem, which occurred in tropical environments where poverty and poor sanitation co-existed, and was commonly treated with mass drug campaigns.

‘There are around 400 million people across the world who are infected with hookworm,’ he said.

‘The sickness caused by hookworm infection mainly affects pregnant and lactating women, and school-aged children, who are at risk of low iron stores or more likely to be seriously affected by iron loss.’

Fifteen Queenslanders took part in the world-first human trial of the live hookworm vaccine, which was undertaken in Q-Pharm Pty Ltd at QIMR Berghofer Medical Research Institute.

Dr Chapman said the vaccine consisted of microscopic hookworm larvae exposed to UV light, which renders the parasites infertile, and triggers the immune system to respond.

‘We were optimistic that by exposing hookworm larvae to UV light they would be impaired, which would make it possible for the human immune system to recognise the infection and develop a lasting immune response,’ Dr Chapman said.

Dr Chapman said it took around 20 days for a hookworm to penetrate the skin, enter the bloodstream and travel through the lungs to the small intestine.

Adult hookworms grow to about one centimetre in length, and hookworm eggs are expelled from the body in the faeces. Larvae hatched from the eggs in warm soil can remain infectious within the soil for up to six weeks.

‘Ultimately, we would know if the vaccine is successful if we saw fewer hookworm eggs in the faeces of participants who were vaccinated.’ And, indeed, this was the case.

Dr Chapman said the next step would be to do a larger study in a developing country where hookworm was endemic, such as the Pacific Islands.

Developing a vaccine that makes people immune to hookworm infection would potentially improve child mortality, developmental outcomes and maternal health in many parts of the world.

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