Defining delayed immunization.
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Age Factors↗
Biomedical subjects
E R Zell
Publications and source records attributed to E R Zell.
Successes and failures in vaccine delivery: evaluation of the immunization delivery system in Puerto Rico.
The objective of this study was to evaluate immunization delivery and determine reasons for low coverage among preschool-age public clinic attendees in Puerto Rico. In 25 randomly selected clinics, coverage and missed immunization opportunities were assessed in 273 children aged 2 to 59 months, exist interviews were conducted with parents, and providers were interviewed. Two neighborhoods close to the clinics were surveyed to determine parental knowledge about immunizations, and the vaccination status of children in these neighborhoods was assessed. Two hundred seventy-three clinic attendees were interviewed. Among 229 (84%) with vaccination cards, only 126 (55%) had received all indicated vaccines by completion of the clinic visit. Forty-five percent of children with cards in the household survey were not up-to-date. Of 171 (75%) clinic attendees eligible for vaccination at the visit, 118 (69%) missed one or more immunizations at the visit. In addition, half of all children had previously missed one or more immunizations when they had received another vaccine. Missed opportunities occurred because of nonavailability of vaccines, lack of integration of services, provider misconceptions about contraindications, and failure to administer vaccines simultaneously. Other problems included barriers to immunization services and lack of information and education activities. It is concluded that deficiencies in immunization delivery substantially delay immunization and reduce coverage.
Child↗
Pertussis surveillance--United States, 1989-1991.
The licensure of whole-cell pertussis vaccine combined with diphtheria and tetanus toxoids as DTP in the 1940s--and its widespread use in infants and children--led to a dramatic decline in the incidence of reported pertussis. In the prevaccine era, the average annual incidence and mortality for reported pertussis were 150 cases and six deaths per 100,000 population, respectively. From 1989 to 1991, pertussis cases were reported by state and local health departments to CDC through two distinct national surveillance systems: the National Notifiable Diseases Surveillance System (NNDSS) and the Supplementary Pertussis Surveillance System (SPSS). During the period 1989-1991, 11,446 pertussis cases were reported to the NNDSS (4,157 in 1989; 4,570 in 1990; and 2,719 in 1991), for an unadjusted annual incidence of 1.7, 1.8, and 1.1 cases per 100,000 population in 1989, 1990, and 1991, respectively. For the period 1989-1991, case reports were received through the SPSS on 9,480 (83%) of the 11,446 patients reported to the NNDSS. Age-specific incidence and hospitalization rates were highest among children < 1 year of age and declined with increasing age. Long-term trends suggest an increase in the reported incidence of pertussis in the United States since 1976. The peak in reported pertussis cases in 1990 represents the highest annual incidence of pertussis since 1970. However, the incidence of pertussis declined 41% from 1990 through 1991. Whether the long-term increase in reported pertussis is a true increase in incidence is unclear; the observed increase may be a function of improved surveillance.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Mortality and morbidity after high titre measles vaccine in Mexico.
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Child, Preschool↗
Monitoring progress toward US preschool immunization goals.
The United States has achieved over 97% immunization of children by school age and has reduced the incidence of vaccine-preventable diseases by more than 90% since the prevaccination era. However, children often do not receive immunizations at the recommended age, and in densely populated urban areas this delay in immunization has led to epidemics of measles. Correctable deficiencies of the immunization delivery system have been identified in these areas. To respond to needs, the public health infrastructure must be strengthened, and active participation from the private sector must be obtained, both in delivery of immunizations and in assessment of performance. Appropriate action must be stimulated by the provision of timely information on immunization coverage and on indicators of program performance at the local level.
Child, Preschool↗
Prevention of secondary transmission of pertussis in households with early use of erythromycin.
To examine the effectiveness of erythromycin therapy and prophylaxis for pertussis, 17 households with one secondary case or more were compared with 20 households without secondary cases following a community-wide pertussis outbreak in Maricopa County, Arizona, in 1988. There were no significant differences between the two household groups in age distribution of members, size, crowding, race, proportion of children aged 7 months to 18 years with three or more diphtheria and tetanus toxoids and pertussis vaccine doses, or in the age distribution, vaccination status, or medical care of patients with primary cases. However, median intervals from onset of illness in primary cases to initiation of erythromycin therapy (for cases) and prophylaxis (for contacts) were 11 and 16 days, respectively, in households without secondary spread, vs 21 and 22 days, respectively, in households with secondary spread. These results provide additional evidence that erythromycin is effective in the medical management of pertussis and should be initiated promptly to minimize secondary spread.
Adolescent↗
Epidemiological features of pertussis in the United States, 1980-1989.
From 1980 through 1989, 27,826 cases of pertussis were reported to the Centers for Disease Control, for an average annual crude incidence of 1.2 cases/100,000 population. The incidence of reported disease increased in all age groups during this period, but the increase was disproportionately large among adolescents and adults. Infants between 1 and 2 months of age were at highest risk for pertussis (average annual incidence, 62.8/100,000). Infants less than 2 months of age had the highest reported rates of pertussis-associated hospitalization (82%), pneumonia (25%), seizures (4%), encephalopathy (1%), and death (1%). Rates of complication were generally higher among unvaccinated children than among those who had received three or more doses of diphtheria-tetanus-pertussis vaccine; 64% of children 3 months to 4 years of age who had reported cases of pertussis had not been immunized appropriately for their age. Whereas control of pertussis in the United States may be further improved through increased levels of diphtheria-tetanus-pertussis vaccination among eligible infants and children, the use of acellular vaccines in adolescents and adults may also be needed to reduce the burden of pertussis in very young infants.
Age Factors↗
Mumps outbreak in a highly vaccinated population.
From October 1988 to April 1989, a large mumps outbreak occurred in Douglas County, Kansas. Of the 269 cases, 208 (77.3%) occurred among primary and secondary school students, of whom 203 (97.6%) had documentation of mumps vaccination. Attack rates were highest for students attending junior high school (8.0%), followed by high school (2.0%) and elementary school (0.7%). A retrospective cohort study conducted at one junior high school with an attack rate of 12.9% did not find age at vaccination or type of vaccine received (single or combined antigen) to be risk factors for vaccine failure. Students vaccinated more than 4 years before the outbreak appeared to have a higher attack rate than those vaccinated more recently (relative risk (RR) = 4.3; 95% confidence interval (CI) = 0.6, 30.0); however, this association did not exist when risk was evaluated based on number of vaccine doses received. Students who had documentation of receiving only one dose of vaccine were at greater risk than those who had received two doses (RR = 5.2; 95% CI = 1.0, 206.2). Overall, vaccine effectiveness among Douglas County junior high school students was estimated to be 83% (95% CI = 57%, 94%). These data suggest that mumps vaccine failure and the failure to vaccinate have contributed to the relative resurgence of mumps observed in the United States since 1986. The recent change in immunization policy to recommend a two-dose schedule of measles-mumps-rubella vaccine should help reduce the occurrence of mumps outbreaks in highly vaccinated populations.
Age Factors↗
Determinants of vaccination in an urban population in Conakry, Guinea.
A community survey was conducted in 1989 in Conakry, Guinea to determine reasons for low vaccination coverage. Some 377 children aged 12-23 months and their guardians were studied, of whom 204 (54%) had vaccination records. According to their records 19% of children were fully and correctly vaccinated. Thirty-nine incompletely vaccinated children (19% of those with records) had sufficient documented contacts with health services to be fully vaccinated, but at least one immunization opportunity was missed. Multivariate analyses were conducted to identify factors associated with receipt of first dose diphtheria/pertussis/tetanus/oral polio vaccine (DPT/OPV) and with completion of the DPT/OPV series. Factors determining initiation of the series included maternal education (assessed by ability to speak French), household possession of a television, maternal age less than 35 years, child's birth in hospital, and, for non-French speakers, the mother considering vaccination to be affordable. Factors determining completion of the DPT/OPV series, among children who began vaccination, included maternal education, employment, and past positive experience with vaccination services (short waiting times, not having been turned away from vaccination, and not knowing a child with a post-vaccine 'abscess'). Vaccination coverage can be substantially increased in Conakry by improving health services to avoid missed opportunities, following the vaccination schedule correctly, reducing waiting times and avoiding abscesses.
Adult↗
Measles among the Amish: a comparative study of measles severity in primary and secondary cases in households.
An outbreak of measles among a predominantly unvaccinated and susceptible Amish population in Lebanon County, Pennsylvania, offered the opportunity to test the hypothesis that secondary cases in households are more severe than primary cases because the former have more intense exposure and receive a greater virus inoculum. Of 130 measles cases reported between April and June 1988, 119 (92%) constituted a study of disease severity. Severity was assessed by determining frequency and duration of symptoms, length of any hospitalization, and number of days in bed. In a univariate analysis, fewer secondary cases had conjunctivitis (relative risk [RR], 0.67; 95% confidence interval [CI], 0.48-0.96) and headache (RR, 0.37; CI, 0.15-0.86), but more had earache (RR, 9.69; CI, 1.8-202.9) compared with primary cases. Secondary cases had a shorter mean duration of coryza (4.0 vs. 5.0 days, Student's t test, P = .08). However, a logistic regression model that matched by family and controlled for age and sex indicated that there were no significant differences in measles severity among primary and secondary cases in households.
Adolescent↗
Obstacles to achieving immunization for all 2000: missed immunization opportunities and inappropriately timed immunization.
Missed opportunities and inappropriately time immunization substantially reduced the coverage achieved in Mozambique and Guinea Conakry. During coverage surveys in Mozambique, we noted dates of attendance at a health facility for growth monitoring or vaccination, and in Conakry we also abstracted dates of curative care visits from home-based documents. In Mozambique, an average of 84 per cent of children aged 12-23 months had documents, and an average of 53 per cent of children were fully and correctly vaccinated. Among children with cards, 11 per cent had received all vaccines, but at least one dose was applied before the recommended age or with too short an interval between doses (inappropriately timed vaccinations). A further 8 per cent of children had sufficient documented contacts with preventive services to be fully vaccinated, but immunization opportunities had been missed. In Conakry, 54 per cent of 12-23 month-old children had immunization cards, and only 19 per cent were fully and correctly vaccinated. Among children with cards, 9 per cent had received all vaccines, but some were inappropriately timed, and 19 per cent had enough contacts with curative or preventative services to be fully vaccinated, but opportunities had been missed. We recommend that home-based records document all health centre visits, including those for curative care, and that missed opportunities and vaccination timing be routinely evaluated during vaccine coverage surveys.
Guinea↗
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.
Age Factors↗
A profile of mothers giving birth to infants with congenital rubella syndrome. An assessment of risk factors.
To formulate strategies for elimination of congenital rubella syndrome, it is important to identify risk factors for delivering an infant affected by it. We analyzed cases of congenital rubella syndrome in infants born from 1970 to 1985 and reported to either one of two independent Centers for Disease Control surveillance systems. Mothers of infants with congenital rubella syndrome identified in both surveillance systems were disproportionately younger than mothers giving birth in the United States. The risk for delivering an infant with congenital rubella syndrome was approximately 2.5 times higher for blacks compared with whites for both reporting systems. A total of 18% of infants with congenital rubella syndrome born since 1979 were Hispanic (national population average, 7%). Both surveillance systems showed that, although primiparous mothers were at highest risk, 39% of women delivering infants affected by congenital rubella syndrome had had at least one previous live birth, suggesting that postpartum immunization could have prevented these congenital rubella syndrome cases. Young, black, and Hispanic primiparous women represent populations at elevated risk for delivering a congenital rubella syndrome-affected infant and should be specifically targeted for immunization.
Adolescent↗
National Immunization Survey: the methodology of a vaccination surveillance system.
The National Immunization Survey (NIS) was designed to measure vaccination coverage estimates for the US, the 50 states, and selected urban areas for children ages 19-35 months. The NIS includes a random-digit-dialed telephone survey and a provider record check study. Data are weighted to account for the sample design and to reduce nonresponse and non-coverage biases in order to improve vaccination coverage estimates. Adjustments are made for biases resulting from nonresponse and nontelephone households, and estimation procedures are used to reduce measurement bias. The NIS coverage estimates represent all US children, not just children living in households with telephones. NIS estimates are highly comparable to vaccination estimates derived from the National Health Interview Survey. The NIS allows comparisons between states and urban areas over time and is used to evaluate current and new vaccination strategies.
Data Collection↗