Forgoing vaccines has a social cost

I love vaccines. The other day, at my 4-year-old son's annual check-up, a physician's assistant asked me whether I had any questions before she shot him up with a half-dozen varieties, including polio, mumps-measles-rubella and flu, and I said, "Heck no, bring them on!"

I have long known that vaccines are considered among the greatest advances of modern medicine. But it was last winter's flu epidemic that turned me into a fervid vaccine fan. In a flukish cluster of tragedy, I happened to know the families of two otherwise healthy children who died of complications of influenza.

It was a winter of tears and terror. Was there some lethal new strain afoot? Apparently not. Might spreading bacterial "super-bugs" make the flu more dangerous for some? Possibly. It is being investigated.

Most children did not get the flu vaccine last year. It was generally considered optional for those over 5. This year, for the first time, federal health authorities recommend that nearly all children from 6 months up be immunized against flu. For needle-haters, there is a nasal vaccine spray as well.

But I worry about how many will actually get vaccinated. Given last year's deaths, I am more troubled than ever by the antivaccine sentiments swirling in our society, centered on fears that vaccines could be connected to the rise in autism even though there is a strong scientific consensus that no such link has been found.

Such sentiments carry social risks that go far beyond a single family. There is growing evidence that children are the main culprits in spreading flu. Unvaccinated children put both their peers and elders at risk. Last year, 83 children nationwide - four in Massachusetts - died of flu. Overall, 36,000 Americans a year die of it. That puts it up close to breast cancer as a killer.

Of the 83 children who died, only 5 to 10 had been vaccinated, as best as the Centers for Disease Control and Prevention could ascertain. In Massachusetts, among four deaths, only one child had been vaccinated.

The number of children who do not get mandatory school vaccinations remains low - about 1 percent in Massachusetts. But in small pockets of the population, it exceeds 10 percent. And such pockets cause great concern among thousands of pediatricians and public health officials, who warn that if vaccination rates drop too far, we risk backsliding into the bad old days when children routinely died of infectious diseases.

Recently, my sister told me that a friend of hers was passing up all vaccines for her 3-year-old, and planned instead to keep the child's immunity strong with "natural" foods and substances. The decision stemmed from general distrust of the medical establishment, and worries about autism.

I confess, I exploded a little, last winter's deaths still too fresh in my mind. I told my sister I would not want her friend's child to come too close to my children. And I pointed out that her friend was putting not just her own child at risk, but others as well.

There is a public health concept called "herd immunity": If enough members of a group are vaccinated, it is much harder for a "chain of infection" to get going, and everyone is better off, especially children who cannot get immunized for medical reasons.

Take flu. Vaccines do not offer perfect immunity, and flu is a particularly tricky virus to block. Last year's vaccines were only around 44 percent effective on average, though this year is looking better. My children are still vulnerable, even though they have been vaccinated.

But if all the children around them are vaccinated as well, flu is less likely to sweep through their classrooms, and through their own vaccine shield. If, on the contrary, few children around them are vaccinated, they are likelier to catch the flu even though they had the shots themselves.

And children with viruses such as flu infect not only their peers, they imperil other age groups as well, particularly the elderly, who are likeliest to die of winter infections.

Researchers at Children's Hospital Boston and elsewhere have found that schoolchildren are the main "vectors" of flu. Dr. Ken Mandl of Children's calls them "little bioterrorists."

In a paper published this summer, Children's researchers analyzing Boston-area data found a striking link between how many children a community has and how many local adults show up in emergency rooms with flu-like symptoms. A percentage point increase in a community's pediatric population translated into a 4-percent increase in adults with flu.

When you get your child vaccinated, you're getting a "quadruple benefit," said John Brownstein, an assistant professor of pediatrics at Children's. "You're protecting the kid, protecting yourself, protecting your own parents, and protecting the community at large."

I admit, I used to dislike the vaccination process. The shots made my children cry. And the rise in autism is so frightening that it worried me even though I knew that top health authorities and scientists had looked hard for a vaccine link and failed to find one. In particular, scientists have extensively examined the possibility of a link between autism and thimerosal, a mercury-containing preservative still found in some flu vaccines, and found none.

Now that there have been deaths in my extended circle, though, I mainly feel deep gratitude for the option of a vaccine - the chance to do something beyond hand-washing to protect my children.

So what is the risk/benefit ratio of a flu vaccine?

I asked Dr. Joseph Bocchini, chairman of the American Academy of Pediatrics' Committee on Infectious Diseases. The common risks are sore arms and feeling lousy for a day or two, he said. In perhaps one in a million cases, a vaccine can prompt a life-threatening allergic reaction, he said. Similarly, in perhaps one in a million cases or less, flu vaccines have appeared to be linked to a paralyzing neurological disease called Guillain-Barre syndrome.

But the odds of dying from the flu are far greater - as those 83 pediatric deaths last year demonstrate.

Between 10 percent and 25 percent of schoolchildren catch flu every year, the highest "attack rate" of any age group.

Dr. Alfred DeMaria, the top epidemiologist at the state Department of Public Health, predicts that most Massachusetts parents will want to get their children vaccinated against the flu this year.

"It's the best and the right thing to do for their children," he said.