The flu vaccine may not be very effective this winter, according to U.S. health officials who worry this may lead to more serious illnesses and deaths.
Flu season has begun to ramp up, and officials say the vaccine does not protect well against the dominant strain seen most commonly so far this year. That strain tends to cause more deaths and hospitalizations, especially in the elderly.
"Though we cannot predict what will happen the rest of this flu season, it's possible we may have a season that's more severe than most," said Dr. Tom Frieden, director of the Centers for Disease Control and Prevention, at a news conference Thursday.
"They are different enough that we are concerned that protection from vaccination against the drifted H3N2 viruses may be lower than we usually see," CDC director Dr. Tom Frieden told reporters during a teleconference Thursday morning.
"In years when A(H3N2) viruses dominate, we tend to have more severe flu seasons with more hospitalizations and death," said IDPH Medical Director, Dr. Patricia Quinlisk. "Since antiviral medications only work well if taken very early in the illness - usually within 48 hours - it is even more important to see your doctor right away if you have flu symptoms so you can begin the medications."
Officials said two anti-viral medications a doctor can prescribe make flu illness milder, shorter and reduce the risk of ending up in the hospital or dying from influenza. Antivirals work best if started within 48 hours or sooner of when flu symptoms begin, officials said.
"Our message to Iowans is clear," said Quinlisk. "The best way to prevent the flu is the influenza vaccine. The best way to lessen complications of the flu is antiviral medication. The best way to prevent the spread of flu is to stay home when ill."
Such patients should be seen promptly, and perhaps treated immediately with antiviral medications, the CDC advised. If a patient is very sick or at high risk, a doctor shouldn't wait for a positive flu test result to prescribe the drugs ? especially this year, CDC officials said.
The medicines are most effective if taken within two days of the onset of symptoms. They won't immediately cure the illness, but can lessen its severity and shorten suffering by about a day, Frieden said.
He was echoed by Dr. Richard Zimmerman, a University of Pittsburgh flu vaccine researcher. Some doctors may hesitate, reasoning that flu season usually doesn't hit hard until around February. But it appears to have arrived in many parts of the country already and "it's time to use them," Zimmerman said.
he flu tends to be more severe during seasons when H3N2 viruses dominate. Rates of hospitalization and death can be "twice as high or more" during these seasons, Frieden said.
Patients with diabetes, asthma, heart or lung disease, and women who are pregnant are also at higher risk of developing severe illness during an H3N2 season, he said.
A spokesperson for PHAC told CTVNews.ca that he would confirm whether Canadian flu data matches the concerns coming out of the U.S.
According to the latest PHAC FluWatch report, H3N2 is the most common type of influenza that is affecting Canadians. However, there is no mention of whether the strain detected in Canada has drifted.
The vaccine will still offer protection against other influenza strains that have not drifted, such as the H1N1 virus and the influenza B virus, the CDC advised.
However, the agency is recommending that doctors also prescribe antiviral medications such as Tamiflu at the first signs of illness in patients.
The flu season can be unpredictable, Frieden noted, and different virus strains may become more dominant as the season goes on.