The Long-Term Evidence for Vaccines

With some reports saying that the worst of the H1N1 outbreak may have already come and gone this flu season in North America but not worldwide, parents who decided to sit out vaccinations for their children may feel validated. But not only is that strategy risky, it's uninformed, and ignores a larger truth about the benefit of vaccines. Throughout North America and Europe, an anti-vaccination movement has steadily grown over the past two decades, and was recently jet-propelled amid anxiety over immunizing pregnant women and children against the H1N1 "swine flu." The greatest fall-off in child vaccination, and the strongest proponents of various theoretical dangers associated with vaccines, are all rooted in wealthy, mostly Caucasian communities, located in the rich world. At a time when billions of people living in poorer countries are clamoring for equitable access to life-sparing drugs and vaccines for their families, the college-educated classes of the United States and other rich countries are saying "no thanks," even accusing their governments of "forcing" them to give "poison" to their children.

Will the children of these naysaying parents of the rich world turn to Mom and Dad 30 years from now and say, "Thanks for not getting me immunized. Thanks especially for saying no to the flu vaccine?"

Probably not.

If a woman is exposed to influenza while pregnant, or if an unvaccinated child gets the flu in his or her first year of life, the baby's developing brain may be severely damaged by the virus. Analysis of medical records of Americans who were born in the late '50s and early '60s shows that having the mother catch the flu while pregnant increased the chance her child would later develop schizophrenia. It's not a trivial difference: the children of moms who had flu midway during their pregnancies were as much as eight times more likely to become schizophrenic.

Overall, prenatal and infant exposure to influenza is strongly associated with cognitive failures. Babies are born with brains and immune systems that are still developing, and will not be hard-wired and strong until their second year of life. Scientists are increasingly discovering links between viral infections during those precious times, and psychiatric problems ranging from lifelong depression to acute learning deficits. In utero or infancy infection with chickenpox doubles the risk of cerebral palsy, according to Australian researchers. Having rubella during pregnancy increases by 80 percent the chances of severe birth defects in that mother's child, including small brains and hearts, blindness, deafness, and severe learning deficits.

Children who contract measles, chickenpox, or whooping cough can develop encephalitis or meningitis—infections of the central nervous system—which can cause epilepsy, brain damage, and death. Parents cannot protect their children's brains against everything, but the basic battery of vaccines can block the bulk of these viral insults. And the good news is that the still-developing immune system of babies and infants is ripe for the vaccine-induced programming that can confer decades—in some cases, lifelong—protection.