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Biomedical subjects

M Wharton

Publications and source records attributed to M Wharton.

At least 19 recordsLinked to original sources
PubMed2001

Intussusception among infants given an oral rotavirus vaccine.

BACKGROUND: Intussusception is a form of intestinal obstruction in which a segment of the bowel prolapses into a more distal segment. Our investigation began on May 27, 1999, after nine cases of infants who had intussusception after receiving the tetravalent rhesus-human reassortant rotavirus vaccine (RRV-TV) were reported to the Vaccine Adverse Event Reporting System. METHODS: In 19 states, we assessed the potential association between RRV-TV and intussusception among infants at least 1 but less than 12 months old. Infants hospitalized between November 1, 1998, and June 30, 1999, were identified by systematic reviews of medical and radiologic records. Each infant with intussusception was matched according to age with four healthy control infants who had been born at the same hospital as the infant with intussusception. Information on vaccinations was verified by the provider. RESULTS: Data were analyzed for 429 infants with intussusception and 1763 matched controls in a case-control analysis as well as for 432 infants with intussusception in a case-series analysis. Seventy-four of the 429 infants with intussusception (17.2 percent) and 226 of the 1763 controls (12.8 percent) had received RRV-TV (P=0.02). An increased risk of intussusception 3 to 14 days after the first dose of RRV-TV was found in the case-control analysis (adjusted odds ratio, 21.7; 95 percent confidence interval, 9.6 to 48.9). In the case-series analysis, the incidence-rate ratio was 29.4 (95 percent confidence interval, 16.1 to 53.6) for days 3 through 14 after a first dose. There was also an increase in the risk of intussusception after the second dose of the vaccine, but it was smaller than the increase in risk after the first dose. Assuming full implementation of a national program of vaccination with RRV-TV, we estimated that 1 case of intussusception attributable to the vaccine would occur for every 4670 to 9474 infants vaccinated. CONCLUSIONS: The strong association between vaccination with RRV-TV and intussusception among otherwise healthy infants supports the existence of a causal relation. Rotavirus vaccines with an improved safety profile are urgently needed.

Case-Control Studies↗
PubMed2001

Pertussis outbreak in an elementary school with high vaccination coverage.

BACKGROUND: An outbreak of pertussis in a US elementary school with high vaccination coverage was investigated to evaluate vaccine effectiveness and to identify potential contributing factors. METHODS: Survey and cohort study of all 215 students of an elementary school (including 36 case patients) and 16 secondary cases among contacts. RESULTS: Fifty-two pertussis cases were identified (attack rate among students, 17%). Receipt of <3 doses of pertussis-containing-vaccine compared with receipt of complete vaccination series was a significant risk factor for pertussis [relative risk, 5.1; 95% confidence interval (CI), 3 to 8.6]. The effectiveness of the complete vaccination series was 80% (95% CI 66 to 88). No evidence of waning immunity among students was found. The following contributing factors for the outbreak were identified: multiple introductions of pertussis from the community; delays in identification and treatment of early cases; and high contact rates among students. Antimicrobial treatment initiated >14 days after cough onset was associated with increased risk of further transmission of pertussis (relative risk, 10.1; 95% CI 1.5 to 70.3) compared with treatment within 14 days of onset. CONCLUSIONS: This investigation demonstrated the potential for pertussis outbreaks to occur in well-vaccinated elementary school populations. Aggressive efforts to identify cases and contacts and timely antimicrobial treatment can limit spread of pertussis in similar settings. High vaccination coverage should be maintained, because vaccination significantly reduces the risk of the disease throughout the elementary school years, and to ensure timely diagnosis and treatment health care providers should maintain a high index of suspicion for pertussis among elementary school age children.

Adult↗
PubMed2001

Intussusception among recipients of rotavirus vaccine: reports to the vaccine adverse event reporting system.

BACKGROUND: Rotavirus vaccine was licensed on August 31, 1998, and subsequently recommended for routine use among infants. To assess rare adverse events, postlicensure surveillance was conducted. OBJECTIVE: To describe the cases of intussusception among rotavirus vaccine recipients reported to the Vaccine Adverse Event Reporting System from October 1998 through December 1999. SETTING AND PARTICIPANTS: Infants vaccinated with rotavirus vaccine in the United States. OUTCOME MEASURES: Intussusception confirmed by radiology, surgery, or autopsy report with medical record documentation or confirmed by a primary health care provider. RESULTS: There were 98 confirmed cases of intussusception after vaccination with rotavirus vaccine reported to the Vaccine Adverse Event Reporting System; 60 of these developed intussusception within 1 week after vaccination. Based on calculations using vaccine distribution data and intussusception incidence rates from 2 separate databases, an estimated 7 to 16 cases would have been expected to occur in the week after vaccination by chance alone. CONCLUSION: Using a passive surveillance system for vaccine adverse events, we observed at least a fourfold increase over the expected number of intussusception cases occurring within 1 week of receipt of rotavirus vaccine. Other studies were initiated to further define the relationship between rotavirus vaccine and intussusception. In light of these and other data, the rotavirus vaccine manufacturer voluntarily removed its product from the market, and the recommendation for routine use of rotavirus vaccine among US infants has been withdrawn.

Adverse Drug Reaction Reporting Systems↗
PubMed2000

Preparing for elimination of congenital Rubella syndrome (CRS): summary of a workshop on CRS elimination in the United States.

The goal of eliminating indigenous rubella and congenital rubella syndrome (CRS) in the United States in the near future is now within reach, because rubella incidence has been sustained at record-low levels since the mid-1990s. Effective prevention strategies to eliminate CRS and rubella require improvement in the surveillance of CRS and congenital rubella infection (CRI). The purpose of the workshop was to review rubella and CRS epidemiology, as well as current clinical, diagnostic, and laboratory practices, to determine whether new strategies are needed to achieve and document CRS elimination. Workshop participants agreed that surveillance for CRS must be strengthened, particularly through augmented laboratory capabilities, and the case definition for CRS must be revised to reflect the current scientific information available. Further studies of methods are needed to identify high-risk populations and geographic areas for rubella and CRS and to enhance identification of infants with CRS.

Humans↗
PubMed2000

Varicella mortality: trends before vaccine licensure in the United States, 1970-1994.

We examined varicella deaths in the United States during the 25 years before vaccine licensure and identified 2262 people who died with varicella as the underlying cause of death. From 1970 to 1994, varicella mortality declined, followed by an increase. Mortality rates were highest among children; however, adult varicella deaths more than doubled in number, proportion, and rate per million population. Despite declining fatality rates, in 1990-1994, adults had a risk 25 times greater and infants had a risk 4 times greater of dying from varicella than did children 1-4 years old, and most people who died of varicella were previously healthy. Varicella deaths are now preventable by vaccine. Investigation and reporting of all varicella deaths in the United States is needed to accurately document deaths due to varicella, to improve prevention efforts, and to evaluate the vaccine's impact on mortality.

Adult↗
PubMed2000

Evidence for transmission of pertussis in schools, Massachusetts, 1996: epidemiologic data supported by pulsed-field gel electrophoresis studies.

In 1996, 18 of 20 pertussis outbreaks reported in Massachusetts occurred in schools. Pertussis surveillance data were reviewed and a retrospective cohort study was conducted in a high school that experienced an outbreak. Bordetella pertussis isolates from 9 school cases and from 58 cases statewide were examined by use of pulsed-field gel electrophoresis (PFGE). Statewide incidence rates were highest among children aged <1 year, 10-14 years, and 15-19 years (106, 117, and 104 cases per 100,000, respectively). Among 34 confirmed and 20 probable cases at the school, 61% had cough onset within 8 weeks of school opening. Five different PFGE types were identified among the 58 B. pertussis isolates from throughout the state. All 9 isolates from the affected high school were the same PFGE type. School-aged children may play an important role in pertussis epidemics. Consideration should be given to use of acellular pertussis vaccines among school-aged children.

Adolescent↗
PubMed2000

Successful control of epidemic diphtheria in the states of the Former Union of Soviet Socialist Republics: lessons learned.

Epidemic diphtheria reemerged in the Russian Federation in 1990 and spread to all Newly Independent States (NIS) and Baltic States by the end of 1994. Factors contributing to the epidemic included increased susceptibility of both children and adults, socioeconomic instability, population movement, deteriorating health infrastructure, initial shortages of vaccine, and delays in implementing control measures. In 1995, aggressive control strategies were implemented, and since then, all affected countries have reported decreases of diphtheria; however, continued efforts by national health authorities and international assistance are still needed. The legacy of this epidemic includes a reexamination of the global diphtheria control strategy, new laboratory techniques for diphtheria diagnosis and analysis, and a model for future public health emergencies in the successful collaboration of multiple international partners. The reemergence of diphtheria warns of an immediate threat of other epidemics in the NIS and Baltic States and a longer-term potential for the reemergence of vaccine-preventable diseases elsewhere. Continued investment in improved vaccines, control strategies, training, and laboratory techniques is needed.

Adult↗
PubMed2000

Immunogenicity of tetanus-diphtheria toxoids (Td) among Ukrainian adults: implications for diphtheria control in the Newly Independent States of the Former Soviet Union.

After 30 years of control, epidemic diphtheria returned to the Soviet Union in 1990. To develop control strategies, the immunogenicity of the tetanus and diphtheria toxoids (Td) vaccine was assessed. Workers who were 18-67 years old received two Td immunizations separated by 30 days. A neutralization assay determined diphtheria antitoxin (DAT) on enrollment and on days 7, 30, 60, and 425. On enrollment, 43.0% of 488 workers had DAT <0.1 IU/mL. After one dose, 88.5% had DAT >/=0.1 IU/mL, after two doses, 92.2% had >/=0.1 IU/mL and >90% of participants <30 or >/=50 years of age attained >/=1.0 IU/mL; however, only 78.4% of those who were 30-39 years old and 51.8% of those who were 40-49 years old achieved >/=1.0 IU/mL after two doses. To control the epidemic in Ukraine, one Td dose should be administered to virtually the entire population (persons 30-49 years old require three doses of Td for optimal individual protection and to maximize population immunity).

Adolescent↗
PubMed2000

Evaluation of a single dose of diphtheria-tetanus toxoids among adults in Odessa, Ukraine, 1995: immunogenicity and adverse reactions.

Epidemic diphtheria spread to Ukraine in 1991, where it peaked in 1995 with >5,000 reported cases. To refine epidemic control strategies, immunogenicity of a tetanus-diphtheria toxoids vaccine (Td) containing 2 limits of flocculation (Lf) diphtheria toxoid was evaluated. During a mass vaccination campaign, adults at a clinic in Odessa received one dose of Td. At enrollment, 57.2% of 341 study participants had levels of diphtheria antitoxin (DAT) >/=0.1 IU/mL. Thirty and 180 days after receiving one dose of Td, 91.5% and 84.5% of the participants, respectively, had DAT levels >/=0.1 IU/mL. However, among 40- to 49-year-old participants, only 78.8% and 73.8% had DAT levels >/=0.1 IU/mL at 30 and 180 days, respectively. This study suggests that one dose of 2 Lf diphtheria toxoid is highly effective in raising DAT to protective levels in most adults; however, the study also shows that certain age groups, particularly persons 40-49 and, to a lesser degree, 30-39 years old may require additional doses or a complete three-dose primary vaccination series for optimal protection against diphtheria.

Adolescent↗
PubMed2000

Diphtheria toxoid vaccine effectiveness: A case-control study in Russia.

Prior to the completion of this and other studies, low effectiveness of diphtheria toxoid-containing vaccine was suspected to be a major contributing factor to the diphtheria epidemic that began in the Russian Federation in 1990. A vaccine effectiveness study was done in Moscow by enrolling physician-diagnosed cases and 10 control subjects per case. Controls were matched to cases by age (+/-3 months) and clinic registration. Vaccination history was abstracted from a standardized form for case-patients and from clinic vaccination records for control subjects. Two hundred seventeen case-patients and 2169 matched controls were included in the study. Most controls (92%) had received three or more doses of a diphtheria toxoid vaccine, compared with 72% of case-patients. The vaccine effectiveness for three or more doses was 97% (95% confidence interval: 94.3-98.4). Low vaccine effectiveness was not a contributing factor to the diphtheria epidemic in the Russian Federation. To control and prevent diphtheria epidemics, it is necessary to achieve and maintain high vaccination coverage with three or more doses of diphtheria toxoid among adults and children.

Adolescent↗
PubMed2000

How many doses of diphtheria toxoid are required for protection in adults? Results of a case-control study among 40- to 49-year-old adults in the Russian Federation.

During the Russian diphtheria epidemic of the 1990s, adults had an unexpectedly high rate of disease. A retrospective, matched case-control study was done to measure the effectiveness of one, two, or three or more doses of diphtheria toxoid against diphtheria among 40- to 49-year-old Russians. Thirty-nine diphtheria case-patients and 117 controls were studied. Previous vaccinations were included if one dose was received within the previous 10 years. Five cases (13%) and 33 controls (28%) had received three or more doses of vaccine. The matched odds ratio was 0.3 (95% confidence interval, 0.1-0.9) for three or more doses compared with no doses, which was a vaccine effectiveness of 70% (95% confidence interval, 10-90). A trend existed toward milder disease with increasing doses (chi2 test for trend, P=.02). The results suggest that Russian adults, who were unlikely to have acquired immunity to diphtheria through immunization or natural infection, required at least three doses of diphtheria toxoid for reliable protection against disease.

Adult↗
PubMed2000

Epidemic diphtheria in the Newly Independent States of the Former Soviet Union: implications for diphtheria control in the United States.

The re-emergence of diphtheria in the Newly Independent States of the former Soviet Union in the 1990s raised global awareness of the potential for resurgent disease in countries with long-standing immunization programs. In the United States, the large population of susceptible adults and the possibility of a reintroduction of toxigenic strains of diphtheria create a setting in which diphtheria could spread. In addition, at least one focus of continued circulation of endemic toxigenic Corynebacterium diphtheriae has been identified. Few physicians now have expertise in the diagnosis and treatment of persons with diphtheria, and laboratory capacity is lacking throughout the country. These concerns highlight the importance of maintaining high levels of age-appropriate diphtheria toxoid vaccination, surveillance, accessible and reliable laboratory testing, and training of health care providers. Although the risk of resurgence of diphtheria in the United States is low, public health authorities must ensure that the capacity to recognize, diagnose, and control diphtheria is maintained.

Age Factors↗
PubMed2000

Diphtheria surveillance and control in the Former Soviet Union and the Newly Independent States.

The Newly Independent States (NIS) inherited a common approach to diphtheria control from the Soviet Union and maintained a centralized system of surveillance and control managed by Soviet-trained epidemiologists with a shared professional culture. This system had controlled a diphtheria resurgence in the 1980s. In response to the epidemic of the 1990s, NIS health authorities responded with a set of control measures based on the Soviet-era experience. These measures included intensified childhood vaccination, aggressive case investigation, widespread diphtheria screening in institutions, and vaccination of adults in high-risk occupation groups. These measures proved insufficient due to high levels of susceptibility among adults, excessive contraindications to childhood vaccination, and insufficient resources in many countries. After these initial delays in implementing effective measures in some countries, most of the NIS health authorities rapidly and successfully implemented mass immunization of the population against diphtheria once the strategy was adopted and sufficient vaccine was available.

Adult↗
PubMed2000

Epidemiology of diphtheria in South Dakota.

Respiratory diphtheria was one of the most common causes of death among children in the pre-vaccine era. Since the introduction of diphtheria toxoid vaccine in 1920s, and its widespread use by the late 1940s, diphtheria became increasingly rare in the United States. However, through the 1970s diphtheria remained endemic in some states, with reported incidence rates > 1.0 per million population in six states (Alaska, Arizona, Montana, New Mexico, South Dakota, and Washington). Starting in 1980, less than five cases have been reported each year in the United States. The majority of culture-confirmed cases have been associated with importation from other countries. Toxigenic Corynebacterium diphtheriae, the organism causing diphtheria, was thought to have become rare or even have disappeared from previously endemic areas such as South Dakota. However, during four months in 1996, 11 persons (one index case, six patients and four household contacts) in an American Indian community in South Dakota were found to be infected by C. diphtheriae; six of these isolates were toxigenic. The findings in this report indicate that despite 20 years without reported respiratory diphtheria cases, toxigenic C. diphtheriae is still present in South Dakota. The continuous circulation of toxigenic strains of C. diphtheriae emphasizes the need for health care providers throughout South Dakota to promote timely vaccination against diphtheria among persons of all ages and ethnic groups, to be aware of the clinical signs and symptoms of diphtheria so that cases can be promptly diagnosed and treated, and further public health measures can be taken to contain this serious disease.

Adolescent↗
PubMed1999

Changing epidemiology of pertussis in the United States: increasing reported incidence among adolescents and adults, 1990-1996.

Since 1990, the reported incidence of pertussis has increased in the United States with peaks occurring every 3-4 years. On the basis of analysis of pertussis cases reported to the Centers for Disease Control and Prevention, the incidence remained stable among children aged younger than 5 years, most of whom were protected by vaccination. In contrast to 1990-1993, during 1994-1996, the average incidence among persons aged 5-9 years, 10-19 years, and 20 years or older increased 40%, 106%, and 93%, respectively. Since 1990, 14 states reported pertussis incidences of > or =2 cases per 100,000 population during at least 4 years between 1990 and 1996; seven of these states also reported that a high proportion of cases occurred in persons aged 10 years or older. Analysis of national data on pertussis did not provide sufficient information to fully elucidate the relative importance of multiple possible explanations for the increase in the incidence of pertussis in adolescents and adults. Improvement in diagnosis and reporting of pertussis in this age group, particularly in some states, is an important factor contributing to the overall increase.

Adolescent↗
PubMed1998

Tetanus surveillance--United States, 1995-1997.

UNLABELLED: PROBLEM/CONDITIONS: Despite widespread availability of a safe and effective vaccine against tetanus, 124 cases of the disease were reported during 1995-1997. Only 13% of patients reported having received a primary series of tetanus toxoid (TT) before disease onset. Of patients with known illness outcome, the case-fatality ratio was 11%. REPORTING PERIOD COVERED: 1995-1997. DESCRIPTION OF SYSTEM: Physician-diagnosed cases of tetanus are reported by state and local health departments to CDC's National Notifiable Diseases Surveillance System. In addition, since 1965, supplemental clinical and epidemiologic information for cases has been provided to CDC's National Immunization Program. RESULTS: From 1995 through 1997, a total of 124 cases of tetanus were reported from 33 states and the District of Columbia, accounting for an average annual incidence of 0.15 cases per 1,000,000 population. Sixty percent of patients were aged 20-59 years; 35% were aged > or =60 years; and 5% were aged <20 years, including one case of neonatal tetanus. For adults aged > or =60 years, the increased risk for tetanus was nearly sevenfold that for persons aged 5-19 years and twofold that for persons aged 20-59 years. The case-fatality ratio varied from 2.3% for persons aged 20-39 years to 16% for persons aged 40-59 years and to 18% for persons aged > or =60 years. Only 13% of patients reported having received a primary series of TT before disease onset. Previous vaccination status was directly related to severity of disease, with the case-fatality ratio ranging from 6% for patients who had received one to two doses to 15% for patients who were unvaccinated. No deaths occurred among the 16 patients who previously had received three or more doses. Tetanus occurred following an acute injury in 77% of patients, but only 41% sought medical care for their injury. All patients who sought care were eligible for TT as part of wound prophylaxis, but only 39% received it. Tetanus in injecting-drug users (IDUs) with no known acute injury comprised 11% of all cases, compared with 3.6% during 1991-1994. None of the IDU-associated tetanus cases occurred among persons who were known to have been vaccinated. Sixty-nine percent of IDU-associated tetanus cases were reported from California, and 77% of these cases occurred in heroin users. INTERPRETATION: Tetanus remains a severe disease that primarily affects unvaccinated or inadequately vaccinated persons. Adults aged > or =60 years continue to be at highest risk for tetanus and for severe disease. However, the overall incidence of tetanus has decreased slightly since the late 1980s and early 1990s, from 0.20 to 0.15, a result primarily of a decreased incidence among persons aged > or =60 and <20 years. ACTIONS TAKEN: Tetanus is preventable through both routine vaccination and appropriate wound management. In addition to decennial booster doses of diphtheria and tetanus toxoids during adult life, the Advisory Committee on Immunization Practices (ACIP) recommends vaccination visits for adolescents at age 11-12 years and for adults at age 50 years to enable health-care providers to review vaccination histories and administer any needed vaccine. Every contact with the health-care system, particularly among older adults and IDUs, should be used to review and update vaccination status as needed.

Adolescent↗
PubMed1998

Respiratory diphtheria in the United States, 1980 through 1995.

OBJECTIVES: The purpose of this study was to describe the epidemiologic, laboratory, and clinical features of respiratory diphtheria cases reported in the United States during 1980 through 1995. METHODS: Respiratory diphtheria cases reported to the Centers for Disease Control and Prevention were reviewed. Cases were defined as physician-diagnosed cases with signs and symptoms compatible with respiratory diphtheria, including the presence of a pseudomembrane without other apparent cause. RESULTS: From 1980 through 1994, 41 respiratory diphtheria cases were reported; none were reported in 1995, and no secondary cases were identified. Nine (22%) case patients were 4 years of age or younger, and 28 (68%) were 15 years of age or older. None of the case patients were up to date with diphtheria vaccination; 4 unvaccinated children died. Seventeen (43%) of 40 case patients had positive culture results. CONCLUSIONS: Available surveillance data suggest that respiratory diphtheria has become a rare disease in the United States. However, importation and circulation of toxigenic strains continue to present a threat and require achieving and maintaining high coverage with diphtheria toxoid-containing vaccines in both children and adults.

Adolescent↗