Roger H. Bernier

BARRIERS TO VACCINATING PRESCHOOL CHILDREN

Immunization represents one of the most effective tools in preventive medicine. But despite what should be a universal practice, preschool children, particularly in the inner cities, are not being adequately vaccinated. The responsibility for low immunization levels does not rest solely with the parents. Major obstacles within the health care system provide disincentives to immunization. Local resource problems such as inadequate clinic staff, hours, and locations make immunizations difficult to obtain. When comprehensive care is not easily accessible (e.g., requiring appointments weeks or months in advance), policies which require immunization to take place only within such a setting are further barriers. Many opportunities for vaccination are lost when children interact with the health care system but do not receive all the immunizations they need. Policies must be changed to facilitate immunization and to take advantage of all health care visits to provide vaccines.

Immunization of Six-Month-Old Infants with Different Doses of Edmonston–Zagreb and Schwarz Measles Vaccines

Because measles causes an estimated 2 million deaths per year among children in developing countries, including a substantial proportion of infants less than nine months old--the age at which vaccination is recommended--there has been interest in using different strains of vaccine and higher doses to achieve immunization of younger infants. We conducted a randomized trial of three different doses of Edmonston-Zagreb and of Schwarz measles vaccines in infants to evaluate the effect of the strain and dose of vaccine on the serologic response and acute adverse reactions to vaccination. Six-month-old infants received a standard, medium, or high dose of one of the vaccines, and nine-month-old infants received a standard dose. Antibody levels were measured before and after vaccination, by means of a plaque-reduction neutralization assay, in 1061 six-month-olds and 299 nine-month-olds. Edmonston-Zagreb vaccine produced higher rates of seroconversion and seropositivity than comparable doses of Schwarz vaccine. Among the six-month-old infants, the seroconversion rate 18 weeks after vaccination with the standard dose of Edmonston-Zagreb vaccine was 92 percent, that with the medium dose was 96 to 97 percent, and that with the high dose was 98 percent; the rates for the corresponding doses of Schwarz vaccine were 66 percent, 76 percent, and 91 percent, respectively. Higher seroconversion rates were observed with an increase in the dose of either Edmonston-Zagreb (P less than 0.01) or Schwarz (P less than 0.001) vaccine. The seroconversion rates produced by high and medium doses of Edmonston-Zagreb vaccine in six-month-olds were equal to or significantly higher than the rate produced by a standard dose of Schwarz vaccine in nine-month-olds (87 percent). Clinical adverse reactions were not associated with the strain or dose of a vaccine. We conclude that Edmonston-Zagreb vaccine is more immunogenic than Schwarz vaccine in infants and can induce effective immunization against measles at six months of age.

Diphtheria-tetanus toxoids-pertussis vaccination and sudden infant deaths in Tennessee

REFERENCES 1. Niikawa N, Matsuura N, Fukushima Y, Ohsawa T, and Tadashi Kajii T: Kabuki make-up syndrome: A syndrome of mental retardation, unusual facies, large and protruding ears, and postnatal growth deficiency, J PEDIATR 99:565, 1981. 2. Kuroki Y, Susuki Y, Chiyo H, Hata A, and Matsui I: A new malformation syndrome of long palpebral fissures, large ears, depressed nasal tip, and skeletal anomalies associated with postnatal dwarfism and mental retardation, J PEDIATR 99:570, 1981.

Surveillance: Information for Action

Success in immunization requires success in developing an adequate information base. While special studies are important, there is no substitute for surveillance systems. Such systems help evaluate health impact, monitor trends in reported disease and adverse events, and identify areas for more intense investigation. Surveillance data alone have played major roles in immunization strategy changes. Successful surveillance relies on cooperation by health care providers and health departments. While filling out forms and reporting cases may be viewed as a burden by some, such information in the aggregate becomes an important part of the knowledge base used to refocus implementation efforts and potentially to change strategies. Reporting by all physicians is particularly important when reported cases lead to aggressive control actions such as outbreak control. Rapid reporting even when cases are not confirmed can help health departments ensure that needed laboratory specimens are collected and allow control measures to be undertaken before disease containment becomes difficult. In conclusion, any immunization program worth instituting is worth monitoring. Surveillance represents constant vigilance to ensure effective control or elimination of disease.

Measles seroconfirmation using dried capillary blood specimens in filter paper.

Because the incidence of measles has declined in recent years, the potential for confusion of measles with other morbilliform rashes has increased. Routine serologic testing of suspected cases of measles is recommended but it has been hampered, particularly in young infants and children, by the requirement of performing venipuncture. We have compared measles hemagglutination inhibition antibody testing performed on dried capillary whole blood collected on filter paper strips with testing of serum specimens obtained simultaneously by venipuncture. We assessed overall comparability, diagnostic sensitivity and specificity and acceptability and practicality for field use. Of the 125 capillary-venous sets compared, there was a 4-fold difference in hemagglutination inhibition titer between the two types of specimens in only one set (0.8%). Diagnostic sensitivity using capillary blood was 100% and specificity was 96%. Immunoglobulin M assessments on six capillary-venous sets were in complete agreement (three positive in both, three negative in both). In a pilot program of field use, filter paper blood collection was associated with a 97% (36 of 37) success rate in obtaining specimens from individuals with suspected cases of measles. This method of blood collection and testing is an accurate, feasible and acceptable means for seroconfirmation of measles.

Elimination of measles and of disparities in measles childhood vaccine coverage among racial and ethnic minority populations in the United States.

The gap in measles vaccine coverage between white and nonwhite children was as large as 18% in 1970. During the measles epidemic of 1989-1991, attack rates among nonwhite children <5 years of age were 4- to 7-fold higher than rates among white children. Because of the epidemic and of the known disparity in vaccine coverage and risk of disease, a dual strategy to eliminate measles in the United States was implemented: universal interventions likely to reach the majority of children and targeted interventions more likely to reach nonwhite children. In 1992, the gap in coverage between white and nonwhite children was reduced to 6% (from 15% in 1985); the risk of disease among nonwhite children was narrowed to <or=4-fold the risk of white children. During the 1990s, further implementation of the dual strategy resulted in narrowing the gap in vaccine coverage to 2% and elimination of endemic disease in all racial and ethnic populations. This dual strategy deserves close scrutiny by health professionals and policy makers in devising programs to meet the Healthy People 2010 objectives for the elimination of other health disparities.

Priorities for the Use of Hepatitis B Vaccine

General recommendations for the use of hepatitis B virus (HBV) vaccine in the United States have been formulated by the Public Health Service’s Immunization Practices Advisory Committee (the ACIP) (1). The recommendations are based on information about the safety and efficacy of the vaccine and on epidemiologic data. The purpose of our presentation is to review the epidemiologic background of hepatitis, describe the existing ACIP recommendations and the issues they have raised, and assess the likely impact of the current approach in achieving control of HBV-related disease.

Measles vaccination in young adults.

Excerpt To the editor: With the growing problem of measles in adolescents and young adults, the article by Krause and colleagues (1) is timely. We believe, however, that their article may unnecessa...