Hookworm is an intestinal parasite of humans. A polyhydrophobic amino acid (pHAA)-based oral hookworm vaccine candidate with major advantages developed.
- Globally, hookworm infections occur in an estimated 576 to 740 million people
- A new polyhydrophobic amino acid (pHAA)-based vaccine candidate effective against hookworm infections developed
- The vaccine can be orally self-administered
What are the traditional vaccines used against hookworm infections?
- Early hookworm vaccines for veterinary purposes utilize whole parasite larvae-based approaches, which are shown to be not safe.
- Traditional vaccines are typically injectable, so it is not possible to use hookworm parasite (1 cm in size).
- Recombinant forms of larval antigens, e.g., Ancylostoma secretory protein-2 (ASP-2), cause strong allergenic responses in vaccinated human subjects.
How is the oral hookworm vaccine different from traditional vaccines?
- The newly developed polyhydrophobic amino acid (pHAA)-based vaccine candidate has major advantages.
- The hookworm vaccine is peptide-based and do not use whole pathogen/microbe as the vaccine material.
Advantages of oral hookworm vaccine
- It uses only minimal antigenic fragment (p3) of a pathogen protein (APR-1) therefore there is no risk to induce allergic responses, which was reported previously in hookworm vaccine trials in humans.
- This vaccine does not need an adjuvant (immune stimulator), which enhances vaccine safety, as adjuvant can cause side effects.
- The vaccine is not only effective upon injection, but effective after oral administration.
- The vaccine is stable and cheap.
How oral hookworm vaccine reduces worms?
- The alternate vaccine reduced the number of worms by 30% to 40%, whereas the newly developed oral peptide vaccine decreases worms by 94% based on PHAA-p3.
- The current studies are performed on mice. Further studies are planned on hamster and dogs.
- The vaccine is peptide-based, so it is stable in normal storage and transport environment.
- The exact timespan and temperature range will be determined in the future.
Oral hookworm vaccine trial on humans
- Hookworm vaccines do not need to achieve sterilizing protection, i.e., 100% worm reduction, as 80% worm burden reduction in humans is modelled to have a highly positive impact in hookworm-epidemic areas.
- Moreover, hookworm-related morbidity is directly linked to infection intensity, and controlled, low-burden experimental human hookworm infection is well tolerated and has even been shown to carry some health benefits in humans.
- Thus, the vaccine candidates are highly promising and should be progressed to human testing.