Flu: A shot worth taking
My patient, 5-year-old Deanne, struggled to breathe. She inhaled with such force that her ribs were outlined like train tracks with each respiration. But she was tiring; her eyes had a glassy look and her breaths seemed shallow.
Deep in the lungs, where the trachea branched into bronchi and further divided into tiny cul-de-sacs called alveoli, plugs of infected mucus blocked the passage of air. There, the carbon dioxide that should have percolated out instead built up, carbonating Deanne's blood like soda pop. The brain doesn't like that at all, so it creates a terrifying sensation of suffocation as an ultimatum: Breathe harder, breathe faster.
But Deanne's brain was flogging a spent body. As her stricken mother and I looked on, poor Deanne was abandoning her fight.
Across the nation, thousands of children develop Deanne's problem every winter. In the past few weeks, at least five children in the Southwestern United States succumbed to nature's most recent experiment in bioterrorism.
The infection has all the hallmarks of terrorism: The victims are randomly chosen, preferably young and helpless; the attacks exploit political and economic problems; and the epidemics occur at specific and predictable times. Moreover, the agent is extremely contagious, mutates rapidly, and is difficult to treat.
The Journal of the American Medical Association estimated this year that the infection may kill 50,000 Americans annually. And now it's spreading again. According to the Centers for Disease Control, the contagion was "widespread" in only one state -- Texas -- three weeks ago; now it is widespread in more than 13.
The public health menace isn't anthrax (only 11 people were infected in 2002) or smallpox (no one on Earth has been infected for nearly 30 years), though these diseases are well-publicized. It's also safe to say your doctor isn't losing sleep over West Nile virus or SARS. As a pediatrician, what I worry about is the virus that on average kills a full 747's worth of Americans twice weekly, and the one filling Deanne's asthmatic lungs with mucus. What worries me is influenza -- the common flu.
In general, respiratory viruses are forgiving to children, as it was eventually to Deanne. Consider that influenza infects roughly a quarter of all preschool and school-age children annually. A substantial number develop ear infections or asthma attacks, the rare child has a febrile seizure, but the majority just endures the sniffles and a trip to the pediatrician. It kills fewer than 40 children yearly. All told, a parent is more likely to be struck by lightning than have a child die of influenza.
But here's the thing. Infected children like Deanne, however unintentionally, also spread contagion to the most vulnerable people -- the elderly. To see why requires a brief lesson in epidemiology.
In 1854, British physician John Snow deduced that a sewage-containing well caused a deadly cholera outbreak. He concluded that an infectious disease could be eradicated either by destroying the reservoir of contagion (in this case, the well), or by eliminating transmission by the vector (the pump).
Believed to be flu's biological reservoir, birds are nature's laboratory for making virulent new strains. According to the journal Science, two new, lethal flu types jumped from chickens to humans this year. When a similar 1997 event in Hong Kong raised fears of a pandemic like the 1918 "Spanish flu" that killed 500,000 Americans, officials slaughtered every chicken on the island. In epidemiological terms, the reservoir was eliminated, and no pandemic materialized.
Snow had suggested a more-elegant solution in 1854. To immediately halt the cholera epidemic, he removed the pump handle from the tainted well. That is, he left the reservoir alone, but stopped the vector. The same principle applies to flu now.
As anyone with offspring in day care knows, children are great vectors for infection. Following the "Asian flu" pandemic of 1957, the Japanese government required flu vaccination of all schoolchildren. For bad political reasons, the program ended in 1994. A report in the New England Journal of Medicine analyzed the results and found that the defunct campaign had prevented an extraordinary 49,000 deaths annually among older Japanese. That is, one life was saved for every 420 children vaccinated. Later, studies also found that asthma hospitalizations in vaccinated children could be reduced by a third.
Unlike children like Deanne, flu-infected elderly people, who suffer the highest casualties, often get raging fevers and pneumonia, and are far more difficult to treat. Researchers estimate that vaccine rates of about 70 percent among US children could make a major dent in mortality among the elderly -- but today's rates approach a lame 10 percent. The chief reason is that public health authorities have not forcefully pushed universal vaccination, and instead cobbled together a patchwork of "high-risk" groups that is too complicated. The American Academy of Pediatrics now recommends -- this is a selected list -- flu shots for all 6- to 24-month-olds, children with conditions like heart disease or asthma, care givers of infants less than 2 years old, and certain pregnant women. The Centers for Disease Control also recommend, among others, vaccinating people over 50, and when possible, children less than 9.
Skeptics of flu vaccine remain. Some critics state that the vaccine is made using aborted fetuses (not true, though Sabin's famous polio vaccine used fetal tissue). Others point to an outbreak of paralysis following swine flu vaccination in the 1970s (true, the risk increased from a measly one in 100,000 before vaccination to a paltry 1.2 in 100,000 afterward). And others think that almost 20 vaccines before age 2 is enough already.
Ultimately, as a father as well as a pediatrician, I still find it hard to hold my toddler, Jake, for shots. It's even harder when the benefit isn't for him, but the greater public.
I suspect, though, that when he's older and asks what our family did to help others during these uncertain times, I'll tell him: You got a flu vaccine every year and screamed and cried so somebody else could live. You fought the worst kind of bioterror, the kind that stems from indifference and inaction.
Dr. Darshak Sanghavi, a clinical fellow at Children's Hospital and Harvard Medical School, will write a regular column for the Globe. He can be reached at darshak.sanghavi@childrens.harvard.edu.
