Flu Vaccines News 2015: Effectiveness Down to 23% This Season - C.D.C.

Flu vaccines' effectiveness this season is down to just 23 percent, according to the Centers for Disease Control (C.D.C.).

Despite this, the C.D.C. still recommends for people to get flu vaccination "because the vaccine can still prevent some infections by the circulating A (H3N2) viruses as well as by other viruses that may circulate later in the season, including influenza B viruses."

The data came from 2,321 children and adults with acute respiratory illness enrolled at five study sites in the U.S.

Based on the study, the overall effectiveness of seasonal flu vaccine for 2014-1015 to prevent flu virus infection is 23 percent.

The C.D.C. said overall estimates for flu vaccine effectiveness for each season range from 10 to 60 percent.

It said this season's vaccine offers reduced protection, thus the need for additional prevention and treatment methods including proper use of flu antiviral medications for treatment.

"Physicians should be aware that all hospitalized patients and all outpatients at high risk for serious complications should be treated as soon as possible with one of three available influenza antiviral medications if influenza is suspected, regardless of a patient's vaccination status and without waiting for confirmatory testing," said Joe Bresee, branch chief in C.D.C.'s Influenza Division.

The C.D.C. said the flu vaccine effectiveness is dependent on the flu viruses used in vaccine production and the flu viruses that are actually circulating.

H3N2 viruses are dominant this season but about 70 percent of them are different or have drifted from the H3N2 vaccine virus, the reason why there is reduced vaccine effectiveness.

The age and health of patients also influence how well the vaccine works, the C.D.C. said, adding that the vaccine works best in young and healthy people, and less effective in those who are at least 65 years old.

It recommends that people get vaccinated during seasons when drifted viruses are circulating as vaccination can still prevent some infections and reduce severe disease that can result to hospitalization and death.