Protect Against 

Schistosomiasis

 AAHI: 

  • Supports the development of three different schistosomiasis vaccine candidates, currently in early phase clinical testing in Uganda, Brazil, Madagascar, Brukina Faso, and the Netherlands.

Schistosomiasis is caused by infection with parasitic trematode worms. Certain species of fresh-water snails, native to Africa and Brazil, carry the worms, which are shed in larval form. 

There are two forms of the disease - intestinal and urogenital. Intestinal schistosomiasis is caused by four main species of blood fluke:  

  1. S. Mansoni
  2. S. Japonicum
  3. S. Mekongi
  4. S. Guineensis

Urogenital schistosomiasis is caused by S. haematobium.

Once the larval worms, or bloodflukes, are released by the snails, they actively seek hosts. They used their forked tails to penetrate the skin of people who are bathing, simming, or washing clothes. 

Symptoms of intestinal schistosomiasis includes abdominal pain, diarrhea, and blood in the stool. If the disease in more advanced, liver and spleen enlargement is common as a result of accumulated fluid and hypertensive blood vessels. 

The most common symptom of urogenital schistosomiasis is blood in urine. Women also may experience vaginal bleeding and pain during sexual intercourse. 

And while some people die from schistosomiasis, those who survive suffer from debilitating symptoms of chronic disease, such as anemia, infertility, and cancer.

A TREATABLE DISEASE

Praziquantel, an anti-parasitic, treats targeted schistosomiasis cases and is only accessible with a prescription from the doctor. It costs approximately $500 per dose.  

Large-scale preventative chemotherapy treatment is also conducted to mitigate further transmission of disease. 

At risk populations require regular doses of chemotherapy, a powerful toxic chemical that kills all fast-growing cells. 

In 2021, 51 countries were endemic to schistosomiasis with moderate-to-high transmission of disease. The people and communities of all 51 countries required preventive chemotherapy.

Of the estimated 251.4 million people who received preventative chemotherapy, almost half were children. While chemotherapy is highly toxic, even more so to growing individuals, the preventative treatment resulted in an almost 60% reduction in cases in school age children. 

RISK FACTORS

Lack of hygiene and swimming and fishing in infested waters make school-aged children especially vulnerable.

People with jobs in agricultural and fishing industries. 

Women doing domestic chores in infested water, such as laundry. 

 

Treatment works. But transmission has still been reported in 78 countries and the best ways to control it other than zapping the whole body with toxic chemicals, include adequate sanitation, clean water, and snail control. 

Schistosomiasis is a neglected tropical disease that primarily burdens poor and rural remote areas of the world.

CONTENTS

3. What AAHI Does About It

VACCINE CANDIDATES WITH AAHI'S GLA ADJUVANT FORMULATIONS

AAHI is collaborating with partners around the world to develop schistosomiasis vaccines that will deter the worms from considering humans a viable host, and thus may avoid the need for potentially harmful preventive chemotherapy. 

1. SmTSP-2/Alum + GLA-AF

Baylor College of Medicine is conducting a Phase 1/ 2 clinical trial in Uganda evaluating their SmTSP-2 protein on alum combined with AAHI's GLA-AF adjuvant formulation to protect against intestinal schistosomiasis. The vaccine candidate was proven safe and well-tolerated in a Phase 1 clinical trial conducted in Minas Gerais, Brazil (NCT02337855 & NCT03910972).

2. Sm14 + GLA-SE

Developed by researchers in Brazil, this vaccine candidate combines a fatty acid binding protein, Sm14, with AAHI's GLA-SE adjuvant formulation. The Phase 1 clinical trial, sponsored by Oswaldo Cruz Foundation (FioCruz) and conducted in Rio do Janeiro, demonstrated that the vaccine candidate was well-tolerated and induced a favorable immune response (NCT01154049). The researchers recently completed Phase 2 clinical trials in Senegal to protect school children between the ages of 8 and 11 (NCT03799510) and are currently recruiting for a clinical trial in Senegalese adults exploring different vaccine dosing regimens (NCT05658614). 

2. SchistoShield 

SchistoShield (R) combines a recombinant protein, Sm-p80, or calpain, with AAHI's GLA-SE adjuvant formulation, entered clinical testing in 2022 in Seattle, supported by the National Institute of Allergy and Infectious Diseases (NCT05292391). Researchers have plans to commence a Phase 1b clinical trial in Madagascar and Burkina Faso, with a human challenge study planned in the Netherlands.

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