Flu vaccine still provides protection without perfect match to strains

Flu vaccine isn't perfect, but "it's the best technology we have now."

These are the calls public health officials don't want this time of year, from procrastinators who haven't gotten the flu vaccine asking if it's still worthwhile.

"I tell them, 'Of course it is,'" said Doris Hare, communicable disease program manager with the Carroll County Health Department. "The holidays is usually when the [flu] shows its nasty head. Particularly during Christmas."

Warning that this winter could become a severe flu season, local health officials are urging the public to get inoculated for flu. Complicating their jobs is that the vaccine isn't as effective against a virulent strain now circulating.

The U.S. Centers for Disease Control and Prevention said last week that one of the strains — H3N2 — had "drifted," or made genetic changes, after world health leaders recommended that it be included in the vaccine earlier in the year. The CDC said H3 strains are linked to more hospitalizations and deaths.

While no deaths have been reported in Maryland and the number of cases remains low, the number of people who visited the doctor or an emergency department at this point in the season is pacing well ahead of the rate in recent years.

About 6,242 people have visited an emergency department for flu-like symptoms as of the last week in November, state data shows. During the same time last year, 3,874 went to the ER.

Officials won't know the flu's true extent until later in the season, which lasts until spring.

Regardless of the strain going around, doctors and health officials say the flu vaccine remains the best defense against what can be a nasty illness for healthy people and a dangerous one for those with underlying health conditions.

"We're always concerned about the flu because sick people get very sick and even healthy people need to be hospitalized," said Dr. Tyler Cymet, president of the state medical society, MedChi, and an emergency room physician at Prince George's Hospital Center. "All we can do is gear up and try and prevent it, because it is preventable."

Cymet noted that even if people are asking about the vaccine's effectiveness this year, more people have been getting inoculated, according to state data, perhaps because of all the attention given to Ebola, though there is no vaccine for that virus.

Doctors say drifting in flu strains isn't uncommon, and even in a good year, vaccines aren't completely protective.

Healthy young adults might get 70 percent to 90 percent protection when the vaccine is matched well with circulating flu strains, said Dr. Wilbur H. Chen, an infectious disease specialist at the University of Maryland School of Medicine. Older people may receive 50 percent to 70 percent protection.

He said with a mismatch, like this year, the estimate comes down for everyone.

"Some years we're really good at guessing which strains will circulate," said Chen, chief of the adult clinical studies section of Maryland's Center for Vaccine Development. "But even when we have a good vaccine, our vaccines are not optimal. It's the best technology we have now."

Because it takes up to six months to develop vaccine in eggs, Chen said producing a new vaccine mid-season is only considered in cases when there is a shift to a new, potentially dangerous strain, such as during the 2009's H1N1 flu epidemic. That strain is included in this year's vaccine, though few such cases have been reported.

Those most at risk for complications such as pneumonia are the elderly, young children, people with compromised immune systems and pregnant women. Though, Chen added, the flu can become severe for healthy people of any age. And thousands are believed to die from the flu every year.

The virus makes nearly everyone miserable for at least several days, he said. Symptoms can include aches, fever, fatigue, dry cough, sore throat, runny nose and chills.

The CDC recommends that everyone six months and older get vaccinated to protect individuals and build what's called "herd" immunity that affords everyone protection by decreasing the amount of virus spread around.

So far this year, the CDC reported that there have been five pediatric deaths attributed to the flu, none in Maryland.

CDC officials said this year those at highest risk for complications should be treated with antiviral drugs within 48 hours of developing symptoms, whether they have been tested for the flu or not.

Dr. Joshua Sharfstein, Maryland's health secretary, said the drugs could lessen the severity of the symptoms.

"The Department of Health & Mental Hygiene agrees with the Centers for Disease Control and Prevention's advice to still get vaccinated against the flu to maximize protection," he said.

Local health providers are not required to report adult cases of the flu to the health department, and most people recover at home and are never tested.

The state does collect data on "influenza-like illness" from participating doctors and hospitals to determine the severity of the flu season and the spread of the virus.

Though cases appear low in the state now, the virus has spread around Maryland, according to the health department. There are more cases so far this year than at this point in the past two years. Still, flu cases only represent around 2 percent of all visits to doctors and hospitals.

Six states in the South reported a high level of flu activity to the CDC in the week ending Nov. 29, the most recent available.

"It's too early to say for sure that this will be a severe flu season, but Americans should be prepared," said CDC Director Dr. Tom Frieden in a statement. "We can save lives with a three-pronged effort to fight the flu: vaccination, prompt treatment for people at high risk of complications and preventive health measures, such as staying home when you're sick, to reduce flu spread."

In addition to vaccination, officials also recommend coughing into your sleeve and frequent hand washing to prevent the spread of the virus, said Dr. Patrick Chaulk, the Baltimore City Health Department's interim deputy commissioner for the division of disease control.

Under the Affordable Care Act, private plans now cover flu vaccines, so the city has focused its immunization effort on the uninsured and seniors, distributing shots at senior centers, health clinics and homeless shelters.

Chaulk said he hopes people aren't put off of vaccines because the formulation isn't a perfect match this year, but acknowledged even when the vaccine includes the circulating viruses, it is a "public health challenge" to get everyone interested in a shot.

People say they don't have time or are healthy or wrongly believe the vaccine can give them the flu. But he said everyone except those allergic to eggs should be vaccinated.

"It still affords protection, and probably reduces the seriousness of this strain," Chaulk said. "We don't get it right every year, but this is our best public health strategy."

Baltimore Sun Media Group reporter Jon Kelvey contributed to this story

meredith.cohn@baltsun.com

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