Some current developments in immunization

3 Infectious Diseases Newsletter 4(1) January 1985 anaphylactoid reactions--wheal and flare in the skin at the injection site, wheezing--may be consequent on minute residua of egg proteins in hypersensitive persons. The vaccine for the 1984-1985 respiratory disease season was reformulated to include two new variants of influenza virus that appeared during the 1983-1984 season. Antigen to influenza A/Chile/83 (H1N1) and influenza B / U S S R / 1 0 0 / 8 3 replaced the previous H1N1 and B strains. Influenza A (H3N2) viruses are represented by antigen to A/Philippines/82. It is likely that viruses similar to A/Philippines and A/Chile will circulate this winter. Vaccine is recommended particularly for children with cardiopulmonary disorders such as congenital malformations of the heart, cystic fibrosis, and bronchopulmonary dysplasia. Children with severd' asthma should also receive the vaccine if they are not allergic to eggs. Children with sickle-cell disease and other anemias or metabolic disorders will also benefit from immunization. Vaccine is recommended for children with malignancies and immunodeficiencies, but their antibody responses may be inadequate, particularly if they have not experienced previous natural infections with related influenza virus variants. Medical personnel who have regular contact with children at high risk of influenza should be immunized. Studies of hospital units for children showed that nosocomial spread of respiratory virus infections is almost the rule, rather than the exception. Personnel were sometimes implicated in the dissemination of respiroviruses, particularly in neonatal intensive care units and hospital wards for infants. Amantadine may also protect high-risk patients from nosocomial infections during influenza A epidemics. High-risk patients may benefit from amantadine prophylaxis

both when hospitalized during epidemics and when exposed to a household contact with influenza. The drug can also be prescribed for the contacts of high-risk patients to decrease the risk that they will spread the infection.

Bibliography Glezen WP: Consideration of the risk of influenza in children and indications

for prophylaxis. Rev Infect Dis 2:408-420, 1980. Glezen WP: Viral pneumonia as a cause and result of hospitalization. J Infect Dis 147:765-770, 1983. Glezen WP, Frank AL, Taber LH, Tristan MP, Vallbona C, Paredes A, Allison JE: Influenza in childhood. Pediatr Res 17:1029-1032, 1983. LaMontagne JR, Noble GR, Quinnan GV, Curlin GT, Blackwelder WC, Smith JI, Ennis FA, Bozeman FM: Summary of inactivated influenza vaccine clinical trials, 1978. Rev Infect Dis 5:723-736, 1983.

S o m e Current Developments in Immunization Vincent A. Fulginiti, MD Arizona Health Sciences, Center, The University of Arizona, Tucson, Arizona

The very success of immunizations in reducing, and even eradicating, communicable diseases should argue forcibly for support of immunization programs by the lay and medical community alike. Unfortunately, such is not the case. The problems with the swine influenza vaccine, the campaign by Jonas and Darrell Salk regarding inactivated poliovaccine, and the current controversy surrounding the putative complications of pertussis vaccine have raised questions as to the safety and efficacy of vaccines. This has contributed to a lack of confidence leading many parents to fail to comply with school immunization laws and their physicians' advice. Some of these controversies will be explored and current recommendations reviewed. Pertussis Vaccine In young infants, pertussis is often a devastating illness; but, in the United States, it is at present an uncommon disease. After the discontinuation or reduction of administration of pertussis vaccine in Britain and Japan, major outbreaks with marked morbidity and mortality ensued. By any measure, the © 1985 ElsevierSciencePublishingCo., Inc. 0278-2316/85/$0.00 + 2.20

adverse effects of the disease far outweigh the infrequent adverse effects of the vaccine. Why, then, the controversy? In part, the public outcry has been championed by a few medical persons, by a widely viewed television "documentary," and by a group of parents who call themselves "Dissatisfied Parents Together," the initials of which mirror the most common vaccine employed, DPT. The arguments employed are wide-ranging, but focus on several issues: (a) the vaccine is unsafe, has serious and frequent side-effects that are unrecognized and unreported; (b) the federal government has been lax in recognizing the problem and acting on it; (c) there has been insufficient research in search of a better vaccine; and (d) the disease is not serious, has declined in frequency irrespective of vaccine use, and recommending groups are using unnecessary "scare" tactics to force the vaccine on the unsuspecting public. In my view these are false issues, but, as with many campaigns against established practices, there are small kernels of truth amid the huge amount of chaff. Pertussis vaccine is effective and

4 Infectious Diseases Newsletter 4(1) January 1985 safe; yet, it is not totally effective and not perfectly safe. Local and systemic reactions that" are self-limiting and without sequelae occur in as m a n y as 50%-70% of vaccinees. Severe, even life-threatening, reactions with permanent sequelae in the survivors are rare., Sudden collapse occurs at an estimated rate of 0.06% of injections, and encephalopathy occurs at a rate of 1 : 300,000 injections. Confusing these estimates are occurrences of seizures temporally associated with the administration of D P T and diseases of the central nervous system that afflict the very same age group requiring the vaccine. Unfortunately, seizures, both febrile and nonfebrile, occur in infants. Some occur within a short time after receipt of the vaccine; some are vaccine-induced, and some are not. There is no test or group of tests that promptly distinguishes vaccine causation, and only time and the evolution of a seizure disorder can be indicative. Disorders such as infantile myoclonic seizures and tuberous sclerosis often have their onset in the 2-6-month-old infant, the same age span during which DPT is given. Neither disorder is caused by pertussis vaccine. It is easy to understand how the medically naive might link vaccine administration in a cause-effect relationship; but it is difficult to understand and accept such behavior in medically sophisticated persons. On the issue of a better vaccine, there has been, and still is, much difficulty. Bordetella pertussis contains a variety of toxic moieties; to date, efforts to remove toxic materials and retain antigenicity and potency have been ineffective. Japanese investigations resulted in an acellular vaccine that, in early field trials in children 2 years old or older, appeared to cause markedly reduced local and systemic reactions and yet retain both antigenicity and efficacy. More recent reports from Japan

indicate that a few of the severe side effects were observed when the vaccine was more widely employed. There is no evidence of laxity in either governmental or private scientific circles; rather, there is a very difficult biologic problem that has not yet been resolved. Compounding and confounding the matter is the occurrence of multiple legal suits against manufacturers of pertussis vaccine. Wyeth Laboratories recently decided to discontinue production of pertussis vaccine, in part due to the legal issues. The American Academy of Pediatrics has vigorously and doggedly pursued the enactment of a vaccine compensation act that would provide aid to those persons injured because of the intrinsic hazards of receiving any vaccine. The Academy did so in negotiating with the " D P T " parents group. The hope for such a legislative solution is to remove the legal threat from decisions concerning vaccine production and use, and to compensate fairly any injured parties. The future of pertussis vaccine is uncertain. The best outcome would be the development of an acellular vaccine that is effective and engenders little or no severe reactions. At the same time, there should be passage of a vaccine compensation act with establishment of a means for implementation. The result would be protection against disease in a calmer climate than currently prevails. In the meantime, the current vaccine should be used according to the revised recommendations of the American Academy of Pediatrics.

cine need only be given once to any person for whom it is indicated. It can be given safely, and with full expectation of efficacy, at the same time that influenza vaccine is administered, so long as different sites are used. Pneumococcal vaccine is indicated for: 1. Persons older than 2 years. 2. Anatomic or functional asplenia. 3. Chronic illness in which pncumococcal infection is a risk to health or life. 4. Patients about to undergo immunosuppressive therapy, preferably 10-14 days prior to beginning such treatment. 5. Closed groups at high risk (eg, residential schools, nursing homes). . A controversial indication is the routine use in persons 50 years of age or older; some experts advocate this use, others dispute it. Contraindications include: 1. Children younger than 2 years of age. 2. Known hypersensitivity to vaccine components (thiomersal, pneumococcal polysaccharides). 3. Previous recipients of a pneumococcal vaccine (adverse reactions may occur). Poliovaccines Live, attenuated, oral poliovaceine (OPV) is still the choice for primary immunization; inactivated virus vaccine (IPV) is an alternative, but it is not recommended. Measles Vaccine

Pneumococcai Vaccine The present pneumococcal vaccine contains 23 (instead of 14) typespecific, capsular polysaccharide antigens, but the indications, efficacy, and contraindications of the prior vaccine pertain. Pneumococcal vac© 1985 ElsevierSciencePublishingCo., Inc. 0278-2316/85/$0.00 + 2.20

The incidence of measles has been reduced dramatically. However, there remain pockets of susceptibility among the unimmunized, uninfected young adult population. The immune status of adolescent, college-age and young adult persons should be ascertained so that the

5 Infectious Diseases Newsletter 4(1) January 1985 live virus vaccine can be offered to vulnerable persons. Rubella Vaccine Despite the ~lramatic reduction in both rubeqla and the congenital rubella syndrome, both diseases continue to occur in child-bearing females. Diligent search for residual nonimmunized persons, especially women, should be a major objective of preventive care. Bibliography Centers for Disease Control: Pertussis surveillance. Morbid Mort Wkly Rep 31:333-336, 1982.

Centers for Disease Control: Pneumocoecal vaccine. Morbid Mort Wkly Rep 30:410-419, 1981. Cherry JD: The epidemiology of pertussis and pertussis immunization in the United Kingdom and the United States: a comparative study. Curr Prob Pediatr 14:1-78, 1984. Cherry JD, Shields WD: Recurrent seizures after diphtheria, tetanus and pertussis immunization. Am J Dis Child 138:904-907, 1984. Committee on Infectious Diseases, American Academy of Pediatrics: pertussis vaccine. Pediatrics 74:303-305, 1984. Joint Committee on Vaccination and Immunlsation: Immunisation against infectious diseases. London, Depart-

ment of Health and Social Security, 1982. Kanai K: Japan's experience in pertussis epidemiology and vaccination in the past thirty years. J Med Sci Biol (Japan) 33:107-143, 1980. Miller DL, Ross EM, Alderslade R, Bellman MH, Rawson NSB: Pertussis immunization and serious neurologic illness in children. Br Med J. 282:1595-1599, 1981. Murphy JV, Sarff LD, Marquardt KU: Recurrent seizures after diphtheria, tetanus and pertussis vaccine immunization. Am J Dis Child 138:908-911, 1984. Sato Y, Kimura M, Fukimi H: Development of a pertussis component vaccine in Japan. Lancet i:122-126, 1984.

the bilirubin 0.7 mg/dl, the transaminases were normal. There was scarring of the right pulmonary apex by roentgenographic examination. Ultrasound examination disclosed a 5.9 × 5.2 cm cystic lesion with irregular borders and low-level internal echoes in the left lobe of the liver. Abdominal computed tomography (CT) scans confirmed the size and location a few centimeters inferior to the pericardium and diaphragm, in close proximity to and compressing the inferior vena cava. Under computed tomographic guidance, aspiration yieldedabout 125 ml of a thick, brownish material that did not contain microorganisms by smear or wet mount examinations, and was sterile. A pigtail c~,lheter was inserted (under computed tomographic guidance) into the lesion, and drainage was continued for 3 days. Treatment with metronidazole (30 m g / k g body wt per day, given as three equal oral portions, 8hourly) was begun before aspiration and was continued for 10 days. Within 48 hours after commencing treatment, the patient defervesced. A gel-diffusion test was posi-

tive for Entamoeba histolytica; three specimens of feces did not contain either trophozoites or cysts. The patient was well when last seen 3 months after treatment.

CASE REPORT

A 65-year-old Mexican-American man was admitted to hospital because of chills, fever, and myalgias that had occurred daily for 3 weeks. Abdominal distention, which had been noted for about 1 year, was not associated with diarrhea or loss of weight. Pulmonary tuberculosis had been diagnosed 17 years prior to admission and had been inadequately treated because of poor compliance. Although the patient had once had a high intake of alcohol in the past, during the years before admission he had not drunk excessively. He was unemployed and spent much of his time in Mexico. On physical examination, he had fever (102°F), bibasilar rales, and tenderness of the right upper quadrant of the abdomen. By percussion, the superior-inferior liver span was 10 cm; a smooth, nontender edge descended 2 cm below the right costal margin on deep inspiration. There was no splenomegaly and no ascites. The hemoglobin was 14.6 g/dl. Of 9,900 leukocytes/btl, 73% were neutrophiles (3% band forms)._The alkaline phosphatase was 210 IU,

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Comment Infection with E. histolytica is world-wide, and it is particularly c o m m o n in tropical countries. Some 15%-30% of the adult population of Mexico is infected. In the United States, endemic foci are associated with poor sanitation, and more recently with male homosexual populations. Hepatic abscess is the most comm o n extraintestinal localization of E. histolytica; only 15% of patients with abscesses also have cysts or trophozoites in their feces. Our patient was typical: a male ( m a l e / female ratio, 10 : 1), middle-aged, of p o o r socioeconomic status, and symptomatic for 2 - 4 weeks before diagnosis. Abdominal pain referred to the right upper quadrant or epigastrium is present in about 80% of patients. Although our patient did not have hepatomegaly, enlargement