Can a flu shot protect against hundreds of strains?
I got the flu shot in November. I got the flu in January. Flu vaccines are only about 60 percent effective, take months to produce, and the immune response lasts for just one flu season.
The virus’s DNA mutates constantly, leading to new strains. This season, government health officials have loudly urged everyone to be immunized, while quietly encouraging the development of a better vaccine that would protect against many more strains of the virus. Boston Globe reports.
- Next year, two firms will produce a quadrivalent vaccine, which contains four strains rather than the three in current vaccines.
- Last week, the U.S. Food and Drug Administration approved the first gene-based flu vaccine -- producing mass quantities of the virus in insect cells instead of chicken eggs (which will make it available to people with egg allergies).
However, according to Michael Osterholm at the University of Minnesota, more funding is needed to develop a universal flu vaccine that would protect against hundreds of flu strains and last for at least a decade – and work for vulnerable populations, like the elderly and those with weakened immune systems.
“No one is investing a sufficient amount of money to get past the initial work,” he says. “It might take up to a billion dollars to get a single universal vaccine onto the market.”
And about five to 10 years.
Research from 2009 has shown that the flu virus has a lollipop-shaped protein -- called hemagglutinin (see photo) -- that acts like key to enter healthy cells and create more flu viruses. The lollipop head changes rapidly and differs from strain to strain. Right now, vaccines target the lollipop head. But a universal vaccine could be designed to work against multiple strains if it aims for the lollipop stem -- which tends not to change.
“If we could destroy this stalk machinery, we could completely disable the flu virus,” says study coauthor Wayne Marasco at the Dana-Farber Cancer Institute.
Researchers have recently begun testing some universal vaccines in small human trials. (On a related note, Medicago has programmed tobacco plants to help produce the avian flu vaccine. Works in mice.)
[Via Boston Globe]
Image: influenza virus / CDC