A Fresh Look at Immunizations By Mark B. Levin, M.D., Louis J. Tesoro, M.D. and Timothy J. Patrick-Miller, M.D. The Pediatric Group, P.A., Princeton

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The 1800's in most large American cities and cities of the world were a time of great turmoil-filthy living conditions, overcrowding, raw sewage in the streets, offensive odors, no place to eliminate waste, and lack of treatment for those afflicted by any number of diseases. There were yearly epidemics of polio, diphtheria, measles, pertussis, influenza and diarrhea. Death from tetanus ("lockjaw") was common. Advances in science and technology have thankfully brought much needed relief from these afflictions. Cities are still crowded, but sanitation greatly reduces the risk of many ailments. Immunizations are available to protect populations from a growing number of disorders. Antibiotics are available to treat those afflicted by numerous bacterial disorders. In fact, these three changes-sanitation, immunization, and antibacterial therapy-have done more to improve health in this country over the last three centuries than any other changes.

While no one argues the value of sanitation, and many have benefited from antibiotics, the importance and value of immunizing our children has been questioned recently. Do children receive too many shots? Do they need them all? Others worry about side effects and safety. Can vaccines cause my child to develop autism? Who's watching out for us? Still others wonder whether vaccines are still needed, since so few Americans suffer from diseases such as polio and diphtheria. Searching for the answers to these and other questions may help us understand the role immunization has played and continues to play in improving our health.

Immunization uses inert, inactive or live attenuated viral antigens to stimulate the body's immune system to provide protection from disease. Excluding influenza vaccine, infants routinely receive fourteen to twenty injections containing eleven antigens. While some parents feel this is too many, the average infant is exposed to over 100,000 environmental antigens during the first year of life alone. A typical streptococcal infection exposes an individual to over ten antigens. Combining antigens allows us to administer fewer injections to children. Pre-release scientific studies have shown that available combination-antigen immunizations are safe and effective. It is generally believed that healthy infants will have no difficulty handling the current immunization schedule and that the benefit of protection from deadly disease will far outweigh any risk.

The diseases for which vaccines offer protection-diphtheria, pertussis, tetanus, polio, hemophillus influenza, hepatitis B, chicken pox, measles, mumps, rubella, pneumococcus, and influenza-all still exist and are dangerous. Only smallpox has thus far been eliminated completely by vaccination, and was thought until recently to no longer constitute a threat. Terrorism and the question of biologic weaponry, has changed that, and we may again see the broad use of the smallpox vaccine. Other diseases are still prevalent in the world. Cases of diphtheria rocked the world with over 100,000 cases and 3,000 deaths reported in the new Soviet republics in the mid-1990's. Earlier in the 90's, smaller epidemics of measles caused thousands to suffer from this disease. Influenza causes yearly scourges, and hepatitis B remains a threat to children and adults alike as the most common infectious cause of death, liver failure and liver cancer. While there are far fewer cases of meningitis because of vaccination against pneumococcus and hemophillus, the threat of this disease remains ever present. Documented outbreaks in unimmunized populations in the U.S., Germany, Sweden, Africa, the U.K. and elsewhere have shown us that failure to vaccinate will lead to the recurrence of epidemics long thought under control.

Because vaccines are given during the first two years of life when neurologic and other disorders commonly declare themselves, vaccines are often erroneously blamed as the cause of the disorders. For example, DPT (diphtheria-pertussis-tetanus vaccine) was blamed for triggering crib death in the 70's. In each instance, in-depth research has cleared vaccines as the cause.

Recently, there has been much public concern about a possible relationship between MMR vaccination and autism and between the mercury containing preservative thimersol and autism. Concern began several years ago when a neurologist in England noted the onset of autism and other neurologic conditions in twelve of his patients during their second year, soon after receiving MMR. He recommended further study to elucidate the problem. Three good controlled studies have been performed since which find no evidence of a causal relationship between MMR and autism. As with crib death and DTP, a temporal relationship was assumed to be causal, but was found to be unrelated.

The story with thimersol is more complicated because it does not involve a single vaccine but is a preservative added to many vaccines. Vaccines packaged in multi-dose vials needed a preservative to prevent contamination with bacteria. Each bottle contains only a small amount of the preservative with an insignificant amount of mercury. The concern was the possible cumulative effect of multiple small doses of mercury in the many vaccines that infants receive. To date, there is no evidence that any child has ever suffered from the effects of this preservative. The risk is theoretical based on a few studies of children exposed to high doses of mercury in their diet (mostly island dwellers eating whale). While there is no proof of a risk, many experts believe that if the risk is real, it is small. Most pediatricians have already stopped using vaccines that contain mercury just to be cautious. Parents with concerns should direct questions to their primary care giver.

While the vaccine program is not perfect, pre-release scientific study assures us that it is safe. Ongoing surveillance assures that post-marketing problems with vaccines will be detected. Two recent examples (polio and rotavirus) will illustrate this. The oral polio vaccine program started in the middle of last century was so effective that polio has ceased to exist in all of the Western Hemisphere and in most of the world. Therefore, the live oral polio vaccine, which in rare cases caused a vaccine related polio syndrome, was recently replaced by a safer, inactivated, injectable form of the vaccine.

Rotavirus, a severe viral cause of vomiting and diarrhea, affects hundreds of thousands of children every year. More than half of these cases among poor children, require admission to hospital for rehydration. The virus is spread by close person to person contact, particularly among very young children in daycare centers. An oral vaccine to prevent rotavirus infection was introduced in the mid-90's. Less than a year after its introduction, there was found to be a small increase in the incidence of intussusception, a serious form of intestinal blockage, among vaccine recipients. The CDC very quickly evaluated the problem and recommended discontinuing the vaccine.

The vaccine story in this country is a long one, with some ups and downs along the way. But we strongly believe the vaccine program to be safe, effective and improving over time. Future articles will look at some of the particular diseases being prevented by immunization and how those vaccines work.

Dr. Mark B. Levin 

Dr. Levin has been a member of the staff at The Pediatric Group since 1977. Currently an attending Pediatrician at the Medical Center at Princeton, he has been Chairman, Department of Pediatrics, Medical Center at Princeton, 1984 to 1986, 1989 to 1992, and past President, Medical and Dental Staff, Medical Center at Princeton, 1987 to 1988. Dr. Levin has served on numerous Departmental and hospital committees. He has published original articles both while at Upstate Medical Center in Syracuse and at The Pediatric Group. He has a wife and three children. Dr. Levin enjoys alpine skiing, jogging, hiking and camping, travel, computers and racquetball.

Dr. Timothy Patrick-Miller Dr. Patrick-Miller has been a member of the staff at The Pediatric Group since 1985. Dr. Patrick-Miller has served on several Departmental and hospital committees. He has published original work while at The Pediatric Group. He and his wife enjoy travel. He also likes hiking, biking, gardening and reading.

Dr. Louis J. Tesoro

Dr. Tesoro has been a member of the staff at The Pediatric Group since 1988. Dr. Tesoro is Attending Pediatrician, Medical Center at Princeton, 1988 to present. He has served on several Departmental and hospital committees and was Chairman, Department of Pediatrics, Medical Center at Princeton from 1996 - 2000. He has lectured at the Universiy of Pennsylvania and has published original articles both while at The Children's Hospital of Philadelphia and at The Pediatric Group.

ŠAll rights reserved, The Pediatric Group, P.A. 2003