Latest flu vaccines offer protection from 4 influenza strains instead of traditional 3
Influenza clinics across Western Pennsylvania are injecting a more comprehensive vaccine formula that doctors hope will undercut flu season before it starts this fall.
Quadrivalent shots guard against four strains of the flu, one more than traditional three-strain, or trivalent, flu shots that are about 65 percent effective in preventing the respiratory disease.
The four-strain blend could appear in as many as half of flu shots in the United States, up from about 25 percent during its introduction last year, according to drug manufacturers and federal health monitors.
“That's projected to increase every year for the next couple years. We're making major strides toward converting all our vaccines to quadrivalent,” said Dr. David Greenberg, vice president for scientific and medical affairs at vaccine maker Sanofi Pasteur in Monroe County.
Doctors said a more powerful shot should mean more flu protection, including for vulnerable people such as pregnant women and diabetics.
“I would say, just don't underestimate it,” said Megan Zell, 28, of Apollo, who landed in an intensive care unit in January with flu and pneumonia. She didn't get a flu shot last year, but she will this year, she said.
“It can hit you really hard. You have to take it seriously.”
The newer formula adds protection against a form of flu that doctors call a B virus, making the vaccine useful against two A strains and two B strains, he said.
The B strains together account for an estimated 25 to 30 percent of flu cases nationwide, although numbers vary widely from year to year.
That variation makes it tough to predict how much more effective quadrivalent shots will be for any particular season, doctors said. Health authorities reconfigure flu shot formulas regularly, based on strains they expect will be prevalent.
“New data show influenza B puts people in the intensive care unit at an equal rate as influenza A. I really think it's a good thing that we have protection against both strains of B,” said Dr. Amesh Adalja, a senior associate at the UPMC Center for Health Security. “Hopefully, our flu season this year will have less B-caused illness because more people are able to get the quadrivalent shot. But any shot is better than no shot.”
Though he encourages people to ask for the four-strain shots, Adalja said, they should accept a three-strain shot if it's what they can find.
Downtown-based UPMC, North Side-based Allegheny Health Network and the Allegheny County Health Department will offer quadrivalent shots at seasonal flu shot clinics, which begin this month. The cost often runs about $25 apiece. Many Medicare and private insurance plans cover the expense.
The federal Centers for Disease Control and Prevention and its Advisory Committee on Immunization Practices has not recommended quadrivalent shots over trivalent vaccines. The committee has not reviewed enough evidence to make such a determination, said Lisa Grohskopf, a CDC medical officer.
She said the four-strain shot is among 13 flu-vaccine products on the domestic market, an increase from eight in 2010. The choices include special shots for people with egg allergies and a higher-dose variety suggested for the elderly, all introduced as researchers and health authorities urge near-universal vaccination rates to curb fatalities.
For many healthy children from 2 to 8 years old, the CDC recommends a nasal spray vaccine. Trials show 55 percent fewer flu cases in children vaccinated through such treatments, compared with youths who receive conventional shots, said Dr. Marc Itskowitz, an internal medicine physician at Allegheny General Hospital in the North Side.
He said doctors have no way to predict the severity of flu season, although others said the nasty season hitting Australia and New Zealand could foreshadow at least a moderate burst of cases in North America. The season in the United States can run from October through May.
“It seems like the years in which no one's expecting anything bad to happen is when we have the worst cases,” Itskowitz said. “Then after there's been a lot of publicity, we have a couple quiet years.”
Between 5 and 20 percent of Americans get the flu each year, and more than 200,000 are hospitalized with complications, according to the CDC. It found annual flu-related deaths ranged from 3,000 to 49,000 people from the late 1970s through 2006.
About 45 percent of the population older than 6 months got a flu shot in the 2012-13 flu season, the most recent season for which federal data are available.
“I think it's important, especially if you're around young children or the elderly. It protects them,” said Kymberli Potersnak , 54, of Port Vue, a registered nurse at UPMC Presbyterian in Oakland.
Adam Smeltz is a staff writer for Trib Total Media. Reach him at 412-380-5676 or firstname.lastname@example.org.