Commentary: China's giant step toward the global eradication of poliomyelitis.
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Child↗
Biomedical subjects
S L Cochi
Publications and source records attributed to S L Cochi.
Paralytic poliomyelitis in Romania, 1984-1992. Evidence for a high risk of vaccine-associated disease and reintroduction of wild-virus infection.
Although poliomyelitis due to wild-virus infection has virtually disappeared from Romania, with no cases having been documented between 1984 and 1989, vaccine-associated paralytic poliomyelitis has been reported at very high rates for over two decades. In November 1990, to decrease the risk of vaccine-associated paralytic poliomyelitis, oral poliovirus vaccine produced in Romania was replaced by imported oral vaccine made by a Western European manufacturer. To better quantify the risk of vaccine-associated paralytic poliomyelitis and the impact of the change in vaccine manufacturer, the authors reviewed clinical, epidemiologic, and laboratory data on poliomyelitis cases that occurred in Romania from 1984 to 1992. Poliovirus isolates were characterized at the US Centers for Disease Control and Prevention. During the period 1984-1992, 132 confirmed cases of paralytic poliomyelitis were reported in Romania, of which 13 were classified as wild-virus-associated, 93 as vaccine-associated, and 26 as "of unknown origin." Wild type 1 poliovirus was isolated during 1990-1992 from nine of 13 (69%) cases in an outbreak that occurred primarily among undervaccinated gypsy children. Vaccine-associated cases were epidemiologically and virologically distinct from wild-virus cases. Of the 93 vaccine-associated cases, 45 children were recipients and 48 were contacts. The overall risk of vaccine-associated paralytic poliomyelitis in Romania (1 case per 183,000 doses of oral poliovirus vaccine distributed) was 14-fold higher than the risk in the United States. The risks of recipient vaccine-associated paralytic poliomyelitis related to the first dose of oral vaccine were similar for Romanian and imported vaccine (1 case per 95,000 doses and 1 case per 65,000 doses, respectively), as were the total risks of vaccine-associated paralytic poliomyelitis. These findings definitively demonstrate a substantially elevated risk of vaccine-associated paralytic poliomyelitis in Romania which was not affected by a change in oral poliovirus vaccine manufacturer.
Child, Preschool↗
Theoretical epidemiologic and morbidity effects of routine varicella immunization of preschool children in the United States.
The authors studied the effects of routine varicella immunization of US preschool children and of implementation of a catch-up program in older children on the age distribution of cases and on overall morbidity, with emphasis on the sensitivity of the results to level of vaccine coverage, duration of protection, responsiveness to boosting, relative residual susceptibility and infectiousness, and degree of morbidity among vaccine breakthrough cases. An age-structured theoretical transmission model was used, with values for vaccine efficacy based on a review of the literature by an expert panel. Although implementation of a vaccination program resulted in a shift in the age distribution of remaining varicella cases toward older ages with higher complication rates, the overall reduction in cases resulted in decreased morbidity as measured by overall number of hospitalizations and number of primary cases. Routine immunization with live-virus varicella vaccine would probably result in a substantial reduction in the number of uncomplicated primary cases of chickenpox, as well as a decreased number of complicated cases requiring hospitalization. The number and age distribution of vaccinated cases would depend strongly on the characteristics of the vaccine. Vaccine efficacy studies in the field should be designed to obtain better estimates of residual susceptibility, residual infectiousness, duration of protection, and effects of boosting by wild-type reinfection.
Age Distribution↗
Cost-effectiveness of a routine varicella vaccination program for US children.
OBJECTIVE: To evaluate the economic consequences of a routine varicella vaccination program that targets healthy children. METHODS: Decision analysis was used to compare the costs, outcomes, and cost-effectiveness of a routine vaccination program with no intervention. Clinical outcomes were based on a mathematical model of vaccine efficacy that relied on published and unpublished data and on expert opinion. Medical utilization rates and costs were collected from multiple sources, including the Kaiser Permanente Medical Care Program and the California Hospital Discharge Database. RESULTS: A routine varicella vaccination program for healthy children would prevent 94% of all potential cases of chickenpox, provided the vaccination coverage rate is 97% at school entry. It would cost approximately $162 million annually if one dose of vaccine per child were recommended at a cost of $35 per dose. From the societal perspective, which includes work-loss costs as well as medical costs, the program would save more than $5 for every dollar invested in vaccination. However, from the health care payer's perspective (medical costs only), the program would cost approximately $2 per chickenpox case prevented, or $2500 per life-year saved. The medical cost of disease prevention was sensitive to the vaccination coverage rate and vaccine price but was relatively insensitive to assumptions about vaccine efficacy within plausible ranges. An additional program for catch-up vaccination of 12-year-olds would have high incremental costs if the vaccination coverage rate of children of preschool age were 97%, but would result in net savings at a coverage rate of 50%. CONCLUSIONS: A routine varicella vaccination program for healthy children would result in net savings from the societal perspective, which includes work-loss costs as well as medical costs. Compared with other prevention programs, it would also be relatively cost-effective from the health care payer's perspective.
Acyclovir↗
Completeness of reporting for paralytic poliomyelitis, United States, 1980 through 1991. Implications for estimating the risk of vaccine-associated disease.
BACKGROUND: Although the risk of vaccine-associated paralytic poliomyelitis (VAPP) has remained relatively constant during the past 30 years, estimates of VAPP depend largely on the completeness of reporting to the existing passive surveillance system. The National Vaccine Injury Compensation Program constitutes an alternative system for reporting VAPP, and data available from this system permitted us to evaluate the completeness of the national poliomyelitis surveillance system. METHODS: We compared cases of paralytic poliomyelitis reported to the national surveillance system (maintained by the Centers for Disease Control and Prevention, Atlanta, Ga) with cases recommended for compensation by the National Vaccine Injury Compensation Program, Rockville, Md, and we calculated the observed completeness of reporting to the national system for 1980 through 1991. A capture-recapture method was also used to estimate completeness of reporting, ie, to account for cases potentially missed by both systems. In addition, we reviewed the epidemiology and updated the risk of VAPP based on the most current information on cases of VAPP. RESULTS: From 1980 through 1991, 105 cases of paralytic poliomyelitis were identified by the Centers for Disease Control and Prevention and National Vaccine Injury Compensation Program systems, 98 (93%) of which were VAPP (average, 8.2 cases per year). The observed completeness of reporting to the Centers for Disease Control and Prevention was 94%, and the estimated completeness of reporting (capture-recapture method) was 81%. The overall risk of VAPP was one case per 2.5 million doses of oral poliovirus vaccine distributed. In the sensitivity analysis, the risk estimates of VAPP remained relatively stable throughout a wide range of assumptions regarding underreporting and specificity of the case definition for paralytic poliomyelitis. CONCLUSION: The risk of VAPP remains virtually unchanged from previous estimates despite the inclusion of previously unidentified VAPP cases. Despite the potential for both underreporting and misclassification of cases, our risk estimates were relatively insensitive to either of these biases. Since both of these biases were in opposite directions, and both probably occurred with low frequency, the risk estimates provided in this report appear valid and approximate the "true" risk of VAPP in the United States.
Adverse Drug Reaction Reporting Systems↗
The Vaccine Adverse Event Reporting System (VAERS).
Immunizations against most vaccine-preventable diseases will be needed indefinitely unless the disease is eradicated. Public acceptance of immunizations may be threatened as vaccine coverage increases and disease decreases, however, due to the increase in both causally and coincidentally related vaccine adverse events. The post-marketing surveillance for such events in the USA in response to the mandatory reporting requirements of the National Childhood Injury Act of 1986. While VAERS has many methodological limitations intrinsic to such systems, it can play an important role in helping to monitor vaccine safety and maintain public confidence in immunizations.
Adverse Drug Reaction Reporting Systems↗
Meeting the challenges of vaccine-preventable diseases in child day care.
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Child↗
Overview of policies affecting vaccine use in child day care.
Vaccination policies for preschool-age children, including those in child day care, have undergone frequent changes within the past several years in response to the development of new vaccines (DTaP, Hib conjugate vaccines), the changing epidemiology of vaccine-preventable diseases (measles), and the establishment of new objectives for the control and elimination of vaccine-preventable diseases (Hib, hepatitis B). The acquisition and spread of vaccine-preventable diseases can be minimized in child day-care settings by vaccinating all children, establishing a continuing system by which all children remain fully vaccinated on schedule, providing educational materials to parents about the recommended schedule of routine childhood vaccines, and implementing new recommendations for vaccine use.
Child↗
Decline of childhood Haemophilus influenzae type b (Hib) disease in the Hib vaccine era.
OBJECTIVE: Effective Haemophilus influenzae type b (Hib) conjugate vaccines were first licensed for use in US children at least 18 months old in December 1987 and for infants at least 2 months old in October 1990. We evaluated trends in Hib disease associated with licensure of Hib conjugate vaccines. DESIGN: Data from two sources, an intensive laboratory-based active surveillance system and the National Bacterial Meningitis Reporting System (NBMRS), were used separately to evaluate disease incidence. Data from vaccine manufacturers on Hib vaccine doses distributed in the United States were compared with trends in Hib disease incidence. RESULTS: The age-specific incidence of Hib disease among children less than 5 years old decreased by 71% from 37 per 100,000 persons in 1989 to 11 per 100,000 persons in 1991 (active surveillance data). Haemophilus influenzae meningitis incidence decreased by 82% between 1985 and 1991 (NBMRS data). Increases in doses of Hib vaccine distributed in the United States coincided with steep declines in Hib disease. Both surveillance systems showed decreased rates of Hib disease in infants less than 1 year old before vaccine was licensed for use in this age group. Haemophilus influenzae type b disease incidence in persons at least 12 years old and pneumococcal meningitis incidence in children less than 5 years old did not change substantially during the same period; therefore, decreased Hib disease in children less than 5 years old is not likely to be explained solely by changes in surveillance sensitivity or decreases in bacterial disease due to changes in medical practice. CONCLUSION: Our data suggest that conjugate vaccines have already had a marked impact on the incidence of Hib disease in the United States, preventing an estimated 10,000 to 16,000 cases of Hib disease in 1991. The decline of disease in infants less than 1 year old before licensure for this age group warrants further investigation.
Adolescent↗
Pertussis in Missouri: evaluation of nasopharyngeal culture, direct fluorescent antibody testing, and clinical case definitions in the diagnosis of pertussis.
No diagnostic test for pertussis in routine use in the United States has both high sensitivity and high specificity. During a statewide increase in the incidence of pertussis in Missouri, we studied the clinical features of 153 patients with suspected pertussis in the Greater St. Louis area from whom a specimen for pertussis culture had been taken between 15 May and 19 September 1989. In this cross-sectional study, nasopharyngeal cultures were more likely to be positive for persons whose specimens were collected < 21 days after cough onset (adjusted rate ratio [RRa] and 95% confidence interval = 3.4; 1.5-8.0) and who were not receiving erythromycin/sulfamethoxazole prior to the culture [RRa = 5.8; 0.8-40.6], who had received fewer than three prior doses of pertussis vaccine [RRa = 1.8; 0.8-4.2], and whose specimen was in transit to the laboratory for < 4 days [RRa = 2.0; 0.8-5.5]. Among children < 5 years of age, spasmodic cough plus a lymphocytosis of > 10,000/mm3 was the acute symptom complex associated with the highest predictive value for a positive culture result (67%). Cough for > or = 14 days plus whoop was sensitive (81%) and specific (58%) for identifying children with culture-confirmed pertussis. Direct fluorescent antibody staining performed well as a screening test for pertussis but requires substantial commitment of personnel and resources. In the absence of a positive culture result, clinical case definitions should be used for decision making (e.g., initiation of antimicrobial therapy and routine case reporting).
Adolescent↗
Fatal respiratory disease due to Corynebacterium diphtheriae: case report and review of guidelines for management, investigation, and control.
Dramatic reductions in the incidence of diphtheria and high levels of childhood vaccination in recent decades have led the United States to establish the goal of diphtheria elimination among persons < or = 25 years of age by the year 2000. In 1990, an unimmunized 25-month-old child died of respiratory diphtheria in Dade County, Florida, before treatment with diphtheria antitoxin could be instituted. Twenty-three asymptomatic household contacts and other close contacts of the child were identified, cultured for Corynebacterium diphtheriae, given antimicrobial prophylaxis, and vaccinated with diphtheria toxoid when indicated. Three contacts (13%) had pharyngeal cultures positive for toxigenic C. diphtheriae of the same type as that causing infection in the deceased child, but no additional cases developed. Although the source of infection was not determined, three other close contacts had recently been to Haiti, where diphtheria is endemic. A serological survey of 396 children < 5 years of age who received care at a medical center in Dade County revealed that 22% lacked protective immunity to diphtheria. Attainment of the goal of diphtheria elimination among persons < or = 25 years of age--and ultimately among all persons--will depend on the maintenance of a high level of clinical awareness of the disease, the prompt institution of preventive measures among close contacts of patients with sporadic cases, and improved vaccination levels among infants, children, and adults.
Antibodies, Bacterial↗
Tetanus surveillance--United States, 1989-1990.
During the period 1989-1990, 117 cases of tetanus were reported from 34 states, for an average annual incidence of 0.02/100,000 population. Fifty-eight percent of patients were > or = 60 years of age, while seven (6%) were < 20 years of age, including one case of neonatal tetanus. Among adults, the risk of tetanus in those > 80 years of age was more than 10 times the risk in persons ages 20-29 years. The case-fatality rate increased with age, from 17% in persons 40-49 years of age to 50% in those > or = 80 years of age. Only 11% of patients reported having received a primary series of tetanus toxoid before disease onset, while 31% lacked a history of tetanus vaccination. Tetanus occurred following an acute injury in 78% of patients. Of patients who sought medical care, only 58% received tetanus toxoid as part of wound prophylaxis. Tetanus remains a severe disease that primarily affects unvaccinated or inadequately vaccinated older adults. Increased efforts are needed to reduce the risk of tetanus among the elderly. Health-care providers should take every opportunity to review the vaccination status of their patients and provide tetanus vaccine when indicated.
Adolescent↗
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↗
Pertussis hospitalizations and mortality in the United States, 1985-1988. Evaluation of the completeness of national reporting.
OBJECTIVE: --To determine the magnitude of hospitalizations for pertussis and pertussis mortality and to estimate the total burden of clinically significant pertussis in the United States. DESIGN: --Capture-recapture methods for estimating population size from independent surveillance systems were used to analyze morbidity and mortality data from case report forms received at the Centers for Disease Control (CDC) from the states, and compared these data with pertussis hospitalizations compiled from a database of US hospitals participating in the Commission on Professional and Hospital Activities-Professional Activities Survey (CPHA-PAS) and death certificate reports compiled by the National Center for Health Statistics (NCHS). POPULATION STUDIED: --All pertussis hospitalizations and pertussis-related deaths in the United States, 1985 through 1988. RESULTS: --We estimated that 13,557 pertussis hospitalizations (95% confidence interval [CI], 12,953 to 14,162) and 98 pertussis deaths had occurred during the 4-year study period (an average of more than 3300 hospitalizations and 25 deaths per year). The completeness of reporting hospitalizations to the CDC was 32% and to the CPHA-PAS, 23%, while the completeness of reporting pertussis deaths to the CDC was 33% and to NCHS, 23%. Patients who were hospitalized with pertussis and reported to CDC were at a higher risk for developing pneumonia (31.0% vs 20.0%, relative risk [RR], 1.6; 95% CI, 1.4 to 1.7), seizures (3.7% vs 2.1%; RR, 1.9; 95% CI, 1.4 to 2.5) and encephalitis (1.2% vs 0.2%; RR, 5.3; 95% CI, 2.4 to 11.6) compared with patients recorded in the CPHA-PAS system. CONCLUSIONS: --Our study suggests that there is substantial underreporting of pertussis, that severe complications of pertussis (including hospitalizations) are reported preferentially to the CDC, and that the national health impact of pertussis based on these indicators is considerably higher than previously published reports have suggested.
Centers for Disease Control and Prevention, U.S.↗
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↗
Epidemiology of poliomyelitis in the United States one decade after the last reported case of indigenous wild virus-associated disease.
Poliomyelitis caused by wild poliovirus has been virtually nonexistent in the United States since 1980, and vaccine-associated paralytic poliomyelitis (VAPP) has emerged as the predominant form of the disease. We reviewed national surveillance data on poliomyelitis for 1960-1989 to assess the changing risks of wild-virus, vaccine-associated, and imported paralytic disease; we also sought to characterize the epidemiology of poliomyelitis for the period 1980-1989. The risk of VAPP has remained exceedingly low but stable since the mid-1960s, with approximately 1 case occurring per 2.5 million doses of oral poliovirus vaccine (OPV) distributed during 1980-1989. Since 1980 no indigenous cases of wild-virus disease, 80 cases of VAPP, and five cases of imported disease have been reported in the United States. Three distinct groups are at risk of vaccine-associated disease: recipients of OPV (usually infants receiving their first dose), persons in contact with OPV recipients (mostly unvaccinated or inadequately vaccinated adults), and immunologically abnormal individuals. Overall, 93% of cases in OPV recipients and 76% of vaccine-associated cases have been related to administration of the first or second dose of OPV. Our findings suggest that adoption of a sequential vaccination schedule (inactivated poliovirus vaccine followed by OPV) would be effective in decreasing the risk of VAPP while retaining the proven public health benefits of OPV.
Humans↗
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↗
Attributable risk of DTP (diphtheria and tetanus toxoids and pertussis vaccine) injection in provoking paralytic poliomyelitis during a large outbreak in Oman.
Although injections administered during the incubation period of wild poliovirus infection have been associated with an increased risk of paralytic poliomyelitis, quantitative estimates of the risk have not been established. During a poliomyelitis outbreak investigation in Oman, vaccination records were reviewed for 70 children aged 5-24 months with poliomyelitis and from 692 matched control children. A significantly higher proportion of cases received a DTP (diphtheria and tetanus toxoids and pertussis vaccine) injection within 30 days before paralysis onset than did controls (42.9% vs. 28.3%; odds ratio, 2.4; 95% confidence interval, 1.3-4.2). The proportion of poliomyelitis cases that may have been provoked by DTP injections was 35% for children 5-11 months old. This study confirms that injections are an important cause of provocative poliomyelitis. Although the benefits of DTP vaccination should outweigh the risk of subsequent paralysis, these data stress the importance of avoiding unnecessary injections during outbreaks of wild poliovirus infection.
Age Factors↗