Individuals concerned about the public health of the American child find themselves at an uncomfortable threshold today. For the first time in modem medical history, there is a threat that the public health status of children will take two steps backward. The first step backward is a product of the erosion of national confidence in the physician as a public health advisor and the pharmaceutical industry as a purveyor of things good for the public health. The second step backward is a result of the current public demand that every medical action have a 100% guarantee of beneficial result. This has resulted in an environment of litigation against the manufacturers of biologies (including vaccines) wherein the profit from their manufacture is exceeded by the cost of legal defense against individuals dissatisfied with the results of their use! This is a totally untenable situation for those who perceive themselves to be child advocates. There may be a number of solutions to these problems, including a concerted effort on the part of physicians caring for children, to educate the American public about the realities of vaccine utilization and the passage of Federal legislation setting up a no-fault system for remuneration of individuals inadvertently harmed by appropriate vaccine utilization.
PERTUSSIS: THE DISEASE
It has been suggested that the best way to justify the utilization of a vaccine to prevent the disease is to make sure that the individuals know well the risks and characteristics of the disease. It is imperative that physicians tell parents that pertussis is a highly communicable (approaching that of measles and chicken pox), acute, severe respiratory tract infection that manifests itself in its typical form by a series of repeated spasmodic coughs ending in the forced inspiration (the "whoop"). The mucous produced by the pertussisinfected patient is extremely tenacious and is expressed from the nose and mouth of the most severely afflicted infants in a bubbly froth. The severe spasmodic cough can produce primary severe lung damage, including bronchiectasis or more subtle lung damage that may have long-term sequelae. The disease may be manifest in association with convulsions and intercranial hemorrhages. Approximately 1 out of 1,000 individuals who contract pertussis disease will die, and 1 in 100 have significant long-term morbidity (Table 1). Recent outbreaks illustrate the morbidity and mortality associated with pertussis disease. In a small outbreak in 1984 involving 102 children, 33 were hospitalized and 1 infant died. In three small epidemics in Texas, 3 children out of 60 died.
An alarming illustration of the increase in incidence of pertussis in the United States was the epidemic reported in Seattle-Kings County, Washington in October 1984 involving over 150 individuals.1 The average number of reported cases in Kings County from 1979 to 1983 was 12. Seven percent of the patients involved in the recent epidemic were hospitalized, but there were no deaths. Nationwide in 1982, the total number of pertussis cases reported was 1 , 342 ; in 1985 it is estimated to be almost 3,000.
THE VACCINE AND ITS USE
The current pertussis vaccine is a suspension of inactivated Bordetella pertussis organisms. Usually, the pertussis vaccine is combined into a single reagent with diphtheria and tetanus toxoids. This preparation is marketed as an aluminum salt-absorbed preparation and is generally administered at 2, 4 and 6 months, with a fourth primary dose at 18 months and a booster between 4 and 6 years of age. Interrupting the recommended schedules or delaying subsequent doses does not appear to lead to the necessity to restart a series regardless of the time elapsed between doses. l Because the incidence rate and severity of pertussis decreases with age and because the vaccine may cause side effects and adverse reactions, pertussis immunization is not recommended for children after the seventh birthday. When the primary series of three doses is given, pertussis immunization prevents disease from and/or the spread of pertussis organisms in approximately 80% of individuals. The few who subsequently acquire pertussis infection have a generally milder disease.3
Side Effects and Adverse Reactions
It Js fairly well-accepted that the pertussis vaccine is the most reactogenic of our currently used agents for routine immunization. Approximately 25% to 50% of those immunized have local reactions, such as redness, swelling or pain at the site of injection. Mild to moderate systemic reactions, such as fever, drowsiness, fretfulness, vomiting, or anorexia occur in 10% to 25% of the recipients, while modera te -to- se ve re systemic events such as fever greater than 40.50C, persistent inconsolable crying (lasting 3 hours or more), unusually high-pitched crying, collapse or convulsions occur relatively infrequently, approximately 1 in 500 injections. Hypotonic/hyporesponsive episodes and convulsions occur in approximately 1 in 2,000 doses and acute encephalopathy and/or primary permanent neurologic defect occur in 1 in 100,000 to 1 in 500,000 doses. One in approximately 10,000 unvaccinated children will suffer neurologic damage after contracting the disease, while only one child in approximately 100,000 receiving the vaccine would suffer the same neurologic damage.
A large case'Controlled study of Sudden Infant Death Syndrome in the United States failed to show an association with receipt of DTP vaccine. Similarly, a careful analysis of infantile spasm failed to show a causal relationship with receipt of DTP vaccine.
Although commonly practiced in the United States, reduction of the volume of DTP administered (ie, less than 0.5 ml/dose) has noi been conclusively demonstrated to reduce the frequency of severe adverse effects. Likewise, data with regard to the immunogenicity of smaller doses do not seem to be available.4 This would seem to be an area where a large research study should be mounted. Minor illness such as upper respiratory tract infection should not be a reason for postponing vaccination. Although it has been demonstrated that pre-term infants have slightly lower and slower serocon vers ion rates than full-term infants, by the time of the third immunization the seroconversion rates for pre-term and term infants were statistically not significantly different,5 Side effects, however, were statistically significantly different with the pre-term infant having approximately one-half the incidence of adverse effects. Therefore, it is concluded that pre-term infants should be immunized at their appropriate chronologic age, ie, 2,4,6 and 18 months post-delivery. The contraindications to pertussis immunization are listed in Table 2. Stable neurologic conditions such as cerebral palsy or developmental delay are not considered a contraindication to receipt of pertussis vaccination. Family history of nervous system disorders is not a contraindication to receipt of pertussis vaccine.
There is, however, a silver lining in the clouds of controversy surrounding the current pertussis vaccine, and that is pressure for the development of an improved product - the so-called acellular vaccine (devoid of whole bacteria). There are a number of prototype acellular vaccines; one under development by the Japanese and currently undergoing clinical trials in Michigan. A toxoid vaccine produced at the NIH will be ready for clinical trials in the near future. Preliminary data with the new acellular pertussis vaccine suggest equal immunogenicity and less reactogenicity.6
The bottom line is that our current routinely used immunizing agents, including pertussis, are generally and reasonably safe. Risk of harm to children and malpractice litigation is greater if the physician fails to immunize the child than if he does appropriately immunize his patients. Until a better pertussis vaccine is available, the old one must suffice. The referral of patients to others, such as Public Health Centers, for immunization, or the granting of unwarranted medical exemptions from immunizations is foolhardy at worst and destructive of the doctor-patient relationship at best. As Fulginiti has noted, pertussis immunization should not he separated from any other aspect of preventive care. It should be provided hy the primary care physician and "not acquired the way one acquires a week's household goods by going from one store to another."7
CONTRAINDICATIONS TO PERTUSSIS IMMUNIZATION
1 Hampet M. Manning D. Sumida S. et al Pertons Washington. 1984 MMWR 1985: 34:390-400.
2 ACIP Diptheria tetanus and pertussia Guidelines for vaccine prophylaxes and exhert preventive measure MMWR 195 34 405-426
3 Geller R. Harden GF Pertumes On its way to becoming a major threat' J Resper 1984, 12:27-38.
4 Barratt L.J. Cody CL cherry JD DTP associated reactions An annals by inejectipon site manufurer prior reactions and done pediatrics 1984 73 31-36\
5 Bernhaum JC daft A. Amodic T et al Response of infants to diptheriatetanus pertussis immunization J Pediat 1985. 107, 184-188.
6 Aoyam T. Murate Y. Kato T. et al Effa of an acellular vaccine in Japan Pediat 985 107:180-183
7 Fulginiti VA. Current topics in immunization Pediatrics Consult 195- 4(2) 1-3
CONTRAINDICATIONS TO PERTUSSIS IMMUNIZATION