Vaccine targets two new flu strains

Two new flu strains are being targeted in this year’s vaccines.

The Centers for Disease Control and Prevention, along with the Food and Drug Administration, World Health Organization and other institutions, study virus samples from around the world each year. From that, they predict which viruses are most likely to spread in the approaching flu season.

Influenza generally spreads earlier in the Southern Hemisphere, allowing officials time to tailor vaccines better for the Northern Hemisphere.

This year’s vaccine mixture targets two A-type viruses and one B-type virus. One, an H1N1-like virus, was also targeted last year; the other two are new.

Influenza mutates rapidly, so new strains are always developing.

The CDC recommends immunization for everyone from 6 months up.

In general, it says, the vaccine works best in older children and younger, relatively healthy adults. However, it also recommends immunization of younger children and older adults.

The CDC said preliminary data for the 2010-11 flu season shows “influenza vaccine effectiveness was about 60 percent for all age groups combined, and that almost all influenza viruses isolated from study participants were well-matched to the vaccine strains.”

Although flu season typically begins in winter, hitting the U.S. hardest in January or February, it can begin as early as October. It takes about two weeks for the body to develop protective antibodies following immunization, according to the CDC.

Vaccine manufacturers are predicting that they will produce several million more doses of vaccine than were distributed last year. One of the vaccines included in this year’s mixture targets an H3N2 virus, which tends to spread rapidly if unchecked.

Yamhill County Public Health has not yet released its clinic schedule for the year.