Schistosomiasis vaccine made in Brazil to be tested in Senegal

Published in September 05, 2016

Researchers from Brazil, Senegal and France are beginning a pivotal test of their vaccine against schistosomiasis, a disease caused by worms that endangers the health of 200 million people worldwide.
Around 350 volunteers living in regions heavily affected by the parasites are to receive the immunization, after an initial evaluation indicated that the vaccine is capable of stimulating the body to confront the invaders.

For scientists at Fiocruz (Oswaldo Cruz Foundation) in Rio de Janeiro, the so-called phase 2 of the vaccine's clinical trials, which aim to test its effectiveness in a relatively large group of people, has a special flavor.
They have been studying the main ingredient in the formula for 30 years, and it is the first time in the world that a vaccine against a worm - and not against a virus or bacteria, as is customary - has advanced so far in the arduous process that precedes commercial release for use in humans.

"For a long time people believed that it would be possible to control this type of disease with anthelmintics [worm medicines]," says doctor Miriam Tendler, from the Experimental Schistosomiasis Laboratory at the Oswaldo Cruz Institute. "In the 1960s and 1970s, drugs were used on a large scale. The problem is that these drugs only increase the number of patients who need constant medical attention, because the person is treated, goes without the disease for a while and ends up re-infected."

The aim of the vaccine is to nip this difficulty in the bud by doing what vaccines do best: generating immunity against the parasite before it even comes into contact with the human body. It was for this purpose that they identified the Sm14 protein ("Sm" stands for Schistosoma mansoni, the species of worm that causes the disease that is prevalent in Brazil). Present on the surface of the worm, it enables it to obtain lipids (fat molecules) from the human host.

The vaccine containing Sm14 causes the body of vaccinated people to produce antibodies (defense molecules) that act specifically against the presence of S. mansoni, as well as cells specialized in protecting the body from invasion, as tests with 20 healthy volunteers recruited in Rio de Janeiro revealed.
Another important ingredient in the vaccine is the adjuvant known as GLA, originally derived from bacteria, which makes the reaction of the body's defense system even more robust.


Over decades of research, the Fiocruz team has discovered that Sm14 is capable of producing immunity to various species of worms that parasitize the intestinal region, similar to S. mansoni.
This allowed the discovery to also lead to the creation of a vaccine for cattle, which is currently at an advanced stage of development, and to the possibility of testing the immunization in Senegal, in regions where there are a large number of cases of schistosomiasis, caused by two different species of worm, S. haematobium and S. mansoni. Each volunteer will receive three doses of the vaccine, one month apart.

The clinical trial in Africa, which should begin in the second half of September 2016, will be carried out in partnership with the NGO "Espoir pour La Santé" ("Hope for Health", in French) and the Pasteur Institute in Lille, France. "They had a very good structure for field testing a molecule of theirs, which ended up not working. But the structure remained, we had good contact with them, and they were excited to help us," says Miriam.

Fiocruz is also negotiating to carry out another arm of phase 2 in a region of the Northeast, an area of the country where there are still endemic outbreaks of the disease (new cases in the country today are relatively rare, reaching just under 30,000 last year).

Another crucial partnership involves the company Orygen Biotecnologia, which will take part in the final stages of the vaccine's development and production. "Our intention is to change the direction of the development of technologies against parasitic diseases, which today are not a big commercial market, they don't attract much interest from industry. We're trying to reverse this logic, with an endemic country developing this technology to help other endemic countries," says Miriam.

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