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They help kids -- but mostly benefit the herd

Special to The Times

Last month, an advisory panel at the Centers for Disease Control and Prevention recommended that all children 6 months and over get the influenza vaccine every year. Currently, children ages 5 to 17 are not included in such recommendations, unless they also have certain health conditions such as asthma and heart disease.

Many parents may be wondering: Is this necessary? And how will it help my child?

Why did the panel decide to alter the vaccine recommendations?

One rationale for universal vaccination is so-called herd immunity. Because kids get sick first and are snotty-nosed transmitters of disease, if they are vaccinated, then the population as a whole -- including the elderly and others for whom the flu can be dangerous -- gains protection too, because of reduced exposure to the virus.

But the advisory panel concluded as well that the vaccine also protects kids from getting the flu, thereby reducing outpatient visits, hospitalizations and the rare deaths that occur among the young.

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In a study based on the 2003-04 flu season -- one that influenced the new recommendation -- CDC researchers reported on details of 153 pediatric deaths from flu. Of those, 16 children would have been newly covered by the recommendation -- that is, they were older than 5 and did not have a chronic health condition. Arguing that this number of deaths is greater for flu than for other diseases for which we have vaccines, the authors of the study called for expanding vaccination in children.

Other experts disagree. They point out that 18 of the deaths in that study were in children younger than 6 months -- a group in which vaccination is not recommended, either now or in the new recommendations. And 12 of the 153 children had been vaccinated, yet they still died.

In addition, says Johannes van der Wouden, an epidemiologist at Erasmus University Medical Center in the Netherlands, the 2003-04 flu season was not a typical one and had more reported flu cases than usual.

“To base universal recommendations for all the states on this one season, I think, is a bit over the top,” he says.

It also wasn’t clear that influenza was really the cause of death in all 153 children, Van der Wouden says. “They found the virus present in the children, but that’s different than saying these deaths are caused by influenza.”

Based on the same evidence as the CDC advisory panel, the Dutch Health Council has made a different decision -- not to vaccinate children. Van der Wouden says this is because those with the highest risk, children younger than 6 months old, can’t be vaccinated, and the effectiveness of the vaccine has not been sufficiently demonstrated in the 6-month-to-2-year-old group.

As for children older than 2, “Influenza doesn’t cause any serious morbidity or mortality, so there’s no reason to include them in the target groups,” Van der Wouden says.

How many children die from flu?

Deaths are rare. Since 2004, the number of children reported to have died in a year from flu in the U.S. has ranged from 46 to 68. So far this year, 24 children have died from flu in the U.S. (By way of comparison, an estimated 36,000 American adults die each year from flu.)

How do children die from flu?

“A couple things happen. No. 1, you get an overwhelming infection -- typically pneumonia,” said Dr. Katherine Poehling, a pediatrician at Wake Forest University Baptist Medical Center in Winston-Salem, N.C. Or a child starts off with flu and then a bacterial infection runs rampant. All of us have various bacteria in our bodies that come and go, Poehling says, and “something about flu makes you more likely to get seriously ill from it.” Every year, she sees a couple kids with “horrendous overwhelming infections” from common bacteria, such as Staphylococcus aureus. Why it happens to some children and not most can be a mystery, although most have medical conditions that put them at extra risk.

Death, when it occurs, can happen fast. One of this winter’s deaths occurred in a 12-year-old girl with asthma in Minnesota. A story in the Minneapolis Star Tribune reported that the girl, who had a cough, woke up one night feeling sick. Her mother gave her Tylenol, but she passed away before morning.

What other burdens does flu cause children?

Children get sick, miss school, visit their pediatricians and are sometimes hospitalized for flu. As with pediatric deaths, the youngest children have the highest risk, “but kids of all ages still end up hospitalized because of influenza,” says Dr. Janice Louie, with California’s Department of Health Services.

The full effect isn’t clear because flu isn’t monitored closely. In California, for example, public health officials follow children who end up in the intensive care unit with flu, but, “We can’t monitor every child hospitalized with influenza because it’s a huge number,” Louie says, let alone the large number with flu who get care as outpatients or who never see a doctor. Over three flu seasons from 2003 to 2006, 266 children were admitted to California intensive care units because of severe flu.

What kind of protection does the flu vaccine offer?

Estimates of the effectiveness of the flu vaccine in preventing influenza infection in children range from 50% to 100%. Even in years when there is a vaccine mismatch, meaning the vaccine fails to target that season’s most common strains, the vaccine has been shown to be 51% to 87% protective, according to the CDC.

How much will the new vaccination recommendations help children?

Studies show that mass vaccinations can sharply reduce death rates from flu in the elderly. How much children will be helped is not yet clear. Poehling has made estimates based on the current vaccination recommendations and is planning to expand her studies to include the new recommendations.

Looking at children under age 5 and using a conservative 50% rate of vaccine effectiveness, she has calculated that in an average year of influenza, one visit to the pediatrician for flu is prevented for every 12 to 42 children who are vaccinated.

Scaling up the statistics, she estimates that if half of the 18 million American children under age 5 were vaccinated with a 50% effective vaccine, there would be 2,250 fewer hospitalizations and 270,000 to 650,000 fewer outpatient visits for children.

Poehling next plans to estimate what the effect will be if similar numbers of children ages 5 to 17 are vaccinated too.

What risks accompany vaccination?

For individuals, the vaccine is very safe beyond a sore arm. Some people feel a little under the weather for a few days, with malaise and perhaps a fever. More severe reactions have occurred in the past, such as in the mid-1970s with the development of Guillain-Barre syndrome, an immune disorder in which part of the nervous system is attacked. That risk is estimated at one in 1 million in adults; there are no data for children.

health@latimes.com


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