A vaccine for middle ear infections

A team of international researchers has moved a step closer to developing a vaccine to protect against middle ear infection, which could also be used for those with poor lung function.

Assistant Professor Tim Perkins, from the University of Western Australia’s (UWA) School of Pathology and Laboratory Medicine, was part of the research team that studied a diverse collection of strains of the bacterial species Haemophilus influenzae, which causes most middle ear infections as well as meningitis.

Professor Perkins said meningitis, middle ear and lung infections can be caused by a wide variety of bacteria and, while vaccines are available for most meningitis infections caused by bacteria, there is no vaccine for middle ear infection - the most common infection in children under the age of five.

“Bacteria often protect themselves with a sugar-like capsule and very often the presence of such a structure is the main reason the bacteria can cause disease,” he said. “Haemophilus influenzae protects itself with a capsule and this structure has been successfully incorporated into a vaccine to induce protection against such bacteria.

“However, there are bacteria from the same species that are not encapsulated (ie, the vaccine will not protect against these strains) and they are often associated with causing middle ear infections in children and lung infections in people with poor lung function.”

To understand if an alternative part of the bacteria’s structure could be used to create a vaccine to protect against these strains, the researchers analysed the genomes of nearly 100 different strains from different parts of the world.

The study characterised a diverse collection of strains from throughout the world and a few components were always found in each strain, Professor Perkins said. These components were also found on the surface of the bacteria and were most likely to interact with human cells, making them ideal to test in new vaccine formulations.

“Not only would a vaccine reduce the incidence of disease in children, it would increase the productivity of working parents and result in fewer GP visits and antibiotic prescriptions,” he said.

Furthermore, said Professor Perkins, vaccines are the cheapest preventable medicine available for infectious diseases. The development of a vaccine would reduce the cost of treating infections, which is currently $380 million per year in Australia alone.