VACCINES

On virtually a daily basis, I have parents question the safety and efficacy of vaccines.  In addition to exposing my own bias (promoting immunization), it is my objective to provide facts and allow parents to make fully informed decisions.  As I write this article, I realize that it is an impossible task to tackle all the diseases, vaccines, studies, and controversies within the scope of a 500-world column.  I came across one text that outlined the risks and complications of vaccine-preventable diseases and the known side-effects of their vaccines.  It is my hope that—while controversies and misinformation will continue to exist—the information I provide will be incontrovertible.

Prior to the development of the following vaccines, 1 in 200 children developed meningitis or severe disease from Haemophilus influenza B, killing 600 children per year and resulting in deafness, seizures, or mental retardation in survivors.  Diphtheria, which killed 15,000 of its 200,000 victims prior to 1920, is still reported in Russia and caused 5000 deaths between 1990 and 1999.   Prior to its vaccine, there were 250,000 cases of pertussis reported each year resulting in 10,000 deaths, brain-damage, pneumonia, seizures, and mental retardation while 20% of people contracting tetanus died of the disease.  Following recommendations for universal immunization, the incidence of H. influenza B disease has declined by 98% (100% in my experience), while there were only 2 and 41 reported cases of diphtheria and tetanus, respectively (as of 2001).  While we still see sporadic cases of pertussis (particular older children with waning immunity), deaths are seen only in babies less than 6 months.  While there are no known side-effects to the HiB vaccine, the DTaP vaccine has been associated with isolated seizures (1 in 14,000), irritability (1 in 1000), and fevers (1 in 16,000 greater than 105F).

Prior to polio vaccination, 20,000 cases were reported in the United States alone.  It caused permanent paralysis in 2% of its victims (1 in 4 of whom died).  While severe allergic reactions to the vaccine are very rare, since its advent, polio has been eradicated in the United States.

Perhaps the most controversial of all vaccines has been the measles, mumps, rubella vaccine (MMR).  Prior to vaccination, virtually everyone in the U.S. developed measles while a smaller number (albeit widespread) developed mumps and rubella.  With regard to the measles, 1 in 17 developed pneumonia and 1 in 2000 developed swelling of the brain (encephalitis).  While we have seen a 99% reduction of the measles, 3 out of 1,000 cases still result in death.  Mumps can lead to encephalitis, infertility in males, and deafness.  Rubella causes arthritis, deafness, mental retardation, and cataracts (congenital rubella syndrome).  The vaccine (MMR) has been associated with fevers (and an isolated seizure) in 1 of 3,000 vaccinated.  More serious allergic reactions occur in 1 in a million.  Currently there is definitive evidence (countless studies with tens of thousands of participants) to disprove any association with autism.

Perhaps the most common vaccine-preventable disease I see—as recently as last week—is varicella (chicken pox).  I often tell parents that their personal experience with chicken pox should not dictate how they treat their children.  Growing up, everyone got the chicken pox, and no one died.  During medical school and residency, however, I saw children die from chicken pox.    One hundred deaths occurred and 10,000 hospitalizations resulted annually from chicken pox, many due to secondary infections (pneumonia) or encephalitis.  It is estimated that a booster vaccination in early childhood will prevent 99% of chicken pox disease (currently 90% prevention with one vaccination).  The remainder of vaccinated children may develop an extremely mild form of the disease.  The vaccine is associated with fever (and an isolated seizure) in 1 in 1000.  A rash may occur, as with the measles, up to 2 weeks after vaccination.

There are other diseases for which we now have vaccines, including rotavirus (the vomiting and diarrhea bug that goes around every winter), pneumococcus (now the leading cause of meningitis and invasive disease in younger children), Neisseria meningitis, hepatitis A and B, and human papilloma virus (HPV), which causes cervical cancer. 

Rather than focus on these diseases, I would like to urge everyone to get a flu shot.  It is not too late.  We generally see widespread influenza in late January and early February, with sporadic cases into late March.  Influenza is not a bad “cold.”  It causes 40,000 deaths per year and 200,000 hospitalizations—and increases yearly (due to an increasing “elderly” population).  Children less than 2 years of age are second only to those over 65 at risk for severe influenza disease.  The vaccine itself is very safe.  It can cause localized soreness and redness.

One final note:  Methylmercury is found in fish and seafood and has been implicated in neurologic disease.  Thimerisol is a preservative found in a limited number of vaccines (multi-dose bottles) and contains ethylmercury which does not lead to neurologic disease.  In an attempt to limit overall mercury exposure, most manufacturers have voluntarily removed the small concentration of thimerisol preservative.  As I always tell parents, the bottom line is:  I love kids and, like most others, went into pediatric medicine to help keep them healthy.  I would never do anything to your child that I wouldn’t ardently do for my own.  If there is one thing you can do to protect your child, it is to vaccinate them!