This week I went to have to get my seasonal influenza shot to help protect against this season’s influenza strains. In English the word influenza if often shortened to just ‘flu’.
The current vaccine used is what’s known as a quadrivalent vaccine (4価ワクチン), which helps protect against 4 types of flu virus, 2 A types and 2 B types. The particular vaccine that I received was was an inactivated split type (不活化ワクチン) which means that the viruses were inactivated using a detergent.
At present people usually receive flu vaccines every year because flu viruses often mutate so they can evade our immune system.
However, there are a number of universal vaccines being developed that may offer protection against multiple different types of flu virus.
Influenza viruses have 2 surface proteins that allow them to infect the body
hemagglutinin (ヘマグルチニン), which helps the virus enter the cell, and neuramidase (ノイラミニダーゼ), which helps the virus spread among cells.
Vaccines often target the hemagglutinin protein. Hemagglutinin looks a little like a mushroom and the end of the the protein or head is highly changeable meaning that new vaccines have to be developed every year. The stalk of the protein, however, is more conserved, meaning it doesn’t change and new vaccines are trying to target part of the virus structure. These new types of vaccine could offer protection against multiple different strains of influenza and offer immunity for years.
At the moment only one universal vaccine for flu is in a phase 3 trial but there are more to follow. If you would like to know more you can read about them here.
First Universal Flu Vaccine to Enter Phase 3 Trial, The Scientist Magazine 2018