Expert advises flu shots, says virus knocking at state’s door

— An influenza researcher with St. Jude Children’s Research Hospital urged science students at the University of Arkansas to get their flu shots this year because of what looks to be a relatively intense flu season.

“Right now, there’s no reported flu activity in Arkansas,” Stacey Schultz-Cherry, an associate member of the Department of Infectious Diseases at the well-known Memphis children’s hospital, said Friday during a seminar in a nearly packed lecture hall on the Fayetteville campus.

But with an early appearance in Texas and its subsequent arrival in neighboring states, the 2012-13 flu bug is knocking on Arkansas’ door, Schultz-Cherry said.

According to the most recent weekly flu activity report from the federal Centers for Disease Control and Prevention for the week ending Oct. 27, the flu has arrived in every state bordering Arkansas - Tennessee, Mississippi, Louisiana, Texas, Oklahoma and Missouri - at a “sporadic” level.

That’s a 4 on a scale of 1 to 5 in intensity, with the most intense being “widespread” at 1, followed by “regional,”“local,” “sporadic” and “no activity.” A sixth category, “no report,” applies to states or U.S. territories that offer no report to the CDC.

Two weeks earlier, Missouri also had no flu activity; but by Oct. 27, Arkansas appeared as a “no activity” island on the CDC’s map.

Though the timing of flu season in Arkansas can vary, state health officials have said a typical season starts in mid-December, peaks in late January or early February, and ends in mid- to late March. In recent years, the Arkansas Department of Healthhas been holding mass flu clinics for the public and for schoolchildren around the state beginning in October to give time for the vaccination to activate people’s immune systems against the three flu strains it targets each year.

The university billed Schultz-Cherry, who also has worked with the pathobiological sciences department at the University of Wisconsin-Madison, as a “world leader” in influenza vaccine development and outbreak monitoring.

Her laboratory has identified a new antiviral peptide that potentially could be used as an adjuvant, a substance added to a vaccine to help the body launch a better immune response to the virus.

Schultz-Cherry told the students that, despite the limitations of modern-day flu vaccines and the many unknowns about the evolutions of the flu virus and its modes of operation, getting a flu vaccination is still the best way to avoid infection and avoid infecting people nearby.

Not everyone has a robust immune system to fight off the virus. For instance, the elderly and children are more susceptible to getting it, she noted. That includes healthy children, but particularly children whose immune systems are suppressed by cancer or other diseases and conditions. That’s why St. Jude’s research includes the flu.

While on her flu-shot soapbox with the students Friday, for those who prefer to get flu shots once every few years, Schultz-Cherry offered a few reasons why the 2012-13 season is a good time to get the vaccine.

One reason is the early emergence of sporadic flu in Arkansas’ neighboring states and a majority of others - the weekly CDC report ending Oct. 27 listed 33 such states and the District of Columbia.

Arkansas was among a dozen states - the others are Illinois, Kansas, Maine, Nebraska, Nevada, New Hampshire, New Mexico, Oregon, Utah, Virginia and West Virginia - and Guam reporting no activity.

Another reason Schultz-Cherry offered is that this season, two of the three flu strains that the vaccine targets are new.

The one unchanged from last year is an “A” strain targeting the “2009 novel H1N1”virus, she said, while the new ones are an “A” strain and a “B” strain.

In some years, the three strains in the vaccine don’t change from the previous year, she said.

“Nobody’s done those studies” that would tell you how long a particular vaccine boosts immunity against a particular type of flu, she said.

Each year in September, she and other scientists from around the world convene in Geneva to decide which three strains will go into the vaccine that will be given 13 months later, in October. Manufacturing the vaccine takes six to nine months.

During that span, Schultz-Cherry said, “a lot can happen to that virus.” She was referring to the scientists’ ability to accurately forecast the three strains that will pose the biggest threat more than a year later.

“So we need to have better vaccines,” she said. “We need to be able to make them faster.”

According to the CDC, since the early 1980s, the seasonal flu vaccine has targeted the top two A strains and the top B strain that world health officials predict will be the biggest threat that season.

The “2009 novel H1N1” virus, initially erroneously dubbed a “swine flu” before the CDC announced that it contained a mix of pig, avian and human genes, surprised scientists with its off-season emergence in early 2009. Though comparatively mild in terms of its virulence, it spread rapidly.

This June, the CDC Influenza Division published the first global estimates of the 2009 H1N1 pandemic’s death count. It estimated that 151,700 to 575,400 people worldwide died in the first year the virus circulated. The estimates were more than 15 times higher than lab-confirmed deaths reported to the World Health Organization, which had said for some time that the confirmed numbers were an underestimate.

The 2009 H1N1 flu virus was so different from other strains that it has served as a lesson in which mammals and birds can be “mixing vessels” for new strains of flu, she said.

“We can make any virus we want to in the laboratory,” Schultz-Cherry said, but the 2009 virus was so novel that no scientist would have thought to make one like it.

Researchers used to think that humans couldn’t get the flu virus from ducks, which don’t get sick with the flu but can harbor and shed the virus.

“When ducks migrate, they poop,” she said, and scientists now know this can infect humans.

“What we always thought through the late 1990s was that the virus first had to go through an intermediate species,” she said, such as the duck passing the virus to a pig, which then passed it to a human.

She told the students about cases of pigs dually infected from avian and human sources, and a pig or a bird can be a “mixing vessel” for a new virus.

“Maybe the humans could be the mixing vessels,” she said, adding that scientists are beginning to think other animals may be involved in this as well.

A new area that is emerging in flu research, Schultz-Cherry said, is the toll it can take on people who are obese.

“Obesity is a risk factor for developing severe influenza virus infection,” she said, but scientists still haven’t figured out all the reasons for this. “That could be because the world is becoming more fat.”

What scientists do know is that obesity is associated with an impaired immune response to flu, and she said one reason could be that obesity causes the body to stay in a constant inflammatory response.

“If the mice are obese, they’re more susceptible to influenza,” she said, and there is some thinking that vaccines may not work as long in obese people.

One improvement she suggested for such studies is getting away from the primary use of the body mass index as a measure, since it could muddy the distinction between “stocky” test subjects and the obese.

Investigating obesity is rare in disease studies, Schultz-Cherry said, adding that maybe the exploration by flu researchers will open up a focus on obesity for other disease research.

Northwest Arkansas, Pages 15 on 11/04/2012

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