Charles Vitek

Increase in deaths from pertussis among young infants in the United States in the 1990s.

Background. Severe pertussis primarily occurs among infants (<12 months of age). Despite high levels of immunization, reported pertussis cases increased in the United States in the 1990s among all age groups, including infants. Methods. To characterize fatal pertussis cases, we analyzed pertussis deaths reported to CDC in the 1990s and compared these with data on pertussis deaths reported in the 1980s. Data from national surveillance systems and from available medical records were used, including data from analyses of deaths reported in 1992 through 1995. Results. In 1980 through 1989, 77 pertussis deaths were reported; 61 deaths were among infants (1.67 deaths per million), including 49 among infants <4 months of age. In the 1990s 103 pertussis deaths were reported; 93 deaths were among infants (2.40 deaths per million), including 84 among infants <4 months of age. Of 89 infants with ethnicity data, 31 (36%) were Hispanic; the mortality rate among Hispanic infants (4.77 per million) was higher than among non-Hispanic infants (1.80 per million). Of 76 infants with reported gestational age, 40 (53%) were born at <37 weeks, including 22 (29%) who were born at <35 weeks. Severe pulmonary hypertension was a common lethal complication among infants. Conclusions. Pertussis deaths increased among infants too young to be protected by immunization. A disproportionate share of deaths were complicated by pulmonary hypertension and occurred among Hispanic infants and infants born at <37 weeks gestation. New approaches to prevent infection among infants <4 months of age and improved therapies for pertussis complications are needed.

Guidelines for immunizations in patients with inflammatory bowel disease

During the past 2 decades, medical therapy for Crohns disease (CD) and ulcerative colitis (UC) has grown to incorporate a variety of immunesuppressing agents. At the same time, basic insights into the aberrant mucosal immune response underlying inflammatory bowel disease (IBD) have expanded dramatically. The interplay of host susceptibility to infection and the safety and efficacy of immunization for vaccine-preventable diseases has been explored in other immune-mediated disease states but only rarely in IBD. The purpose of this review is to formulate best-practice recommendations for immunization in children and adults with IBD by considering the effects of the IBD disease state and its treatments on both the safety and efficacy of immunization. To do so, we first considered the routine recommendations for immunization of children, adults and distinct populations at increased risk for vaccine-preventable disease. Because it was rarely possible to examine direct data on safety and efficacy of immunization in IBD populations, we relied to a large extent upon extrapolation from similar populations and from knowledge of basic mechanisms. The literature suggests that efficacy of immunization may be diminished in some patients whose immune status is compromised by immune suppression. However, except for live agent vaccines, most immunizations may be safely administered to patients with IBD even when immune compromised. Conversely, protection against vaccine-preventable illness may be of even greater benefit to those at risk for morbid or lethal complications of infections because of an immune compromised state. We conclude that for most patients with IBD, recommendations for immunization do not deviate from recommended schedules for the general population.

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.

HIV prevalence and associated risk factors among individuals aged 13-34 years in Rural Western Kenya.

Objectives To estimate HIV prevalence and characterize risk factors among young adults in Asembo, rural western Kenya. Design Community-based cross-sectional survey. Methods From a demographic surveillance system, we selected a random sample of residents aged 13-34 years, who were contacted at home and invited to a nearby mobile study site. Consent procedures for non-emancipated minors required assent and parental consent. From October 2003 - April 2004, consenting participants were interviewed on risk behavior and tested for HIV and HSV-2. HIV voluntary counseling and testing was offered. Results Of 2606 eligible residents, 1822 (70%) enrolled. Primary reasons for refusal included not wanting blood taken, not wanting to learn HIV status, and partner/parental objection. Females comprised 53% of 1762 participants providing blood. Adjusted HIV prevalence was 15.4% overall: 20.5% among females and 10.2% among males. HIV prevalence was highest in women aged 25-29 years (36.5%) and men aged 30-34 years (41.1%). HSV-2 prevalence was 40.0% overall: 53% among females, 25.8% among males. In multivariate models stratified by gender and marital status, HIV infection was strongly associated with age, higher number of sex partners, widowhood, and HSV-2 seropositivity. Conclusions Asembo has extremely high HIV and HSV-2 prevalence, and probable high incidence, among young adults. Further research on circumstances around HIV acquisition in young women and novel prevention strategies (vaccines, microbicides, pre-exposure prophylaxis, HSV-2 prevention, etc.) are urgently needed.

A case-control study to determine risk factors for hospitalization for rotavirus gastroenteritis in U.S. children.

Objective: The objective of this case-control study nested within a surveillance study conducted at 3 hospitals (Cincinnati Childrens Hospital Medical Center, Cincinnati, OH; Childrens Hospital of New Orleans, New Orleans, LA; and Hasbro Childrens Hospital, Providence, RI) was to identify risk factors for rotavirus gastroenteritis requiring hospitalization. Patients: Cases were children ≤59 months of age who were admitted with acute gastroenteritis (AGE) and found to have rotavirus infection. Controls were selected from a birth certificate registry (Cincinnati and Providence) or a registry of patients from a large practice consortium in 11 locations (New Orleans). Results: Three hundred forty-nine rotavirus-infected cases and 1242 control subjects were enrolled. Breast feeding was protective against hospitalization for rotavirus AGE for infants <6 months of age. (odds ratio [OR], 5.1; 95% confidence interval [CI], 1.2–13.2). Low-birth-weight (<2500 g) infants had increased risk for hospitalization even beyond the first few months of life (OR, 2.8; 95% CI, 1.6–5.0). Children in child care were more likely to be hospitalized for rotavirus AGE than those cared for at home, particularly those ≥24 months of age (OR, 3.0; 95% CI, 1.8–5.3). Other characteristics associated with rotavirus AGE hospitalization were children <24 months of age covered by Medicaid or without insurance (OR, 2.1; 95% CI, 1.4–3.2) and having another child in the house <24 months of age (OR, 1.6; 95% CI, 1.1–2.3). The data suggest that maternal age <25 years (OR, 1.4; 95% CI, 1.0–2.0) and a mother with less than a high school education (OR, 1.5; 95% CI, 1.0–2.3) may also increase risk of rotavirus hospitalization. Conclusion: There are socioeconomic and environmental factors and aspects of the childs medical and dietary history that identify children at risk for hospitalization with rotavirus AGE.

Diphtheria in the Russian Federation in the 1990s

A resurgence of diphtheria spread throughout the Russian Federation in the early 1990s; diphtheria had been well controlled, but circulation of toxigenic strains of Corynebacterium diphtheriae had persisted since the implementation of universal childhood vaccination in the late 1950s. More than 115,000 cases and 3,000 deaths were reported from 1990 to 1997, and, in contrast to the situation in the prevaccine era, most of the cases and deaths occurred among adults. Contributing factors included the accumulation of susceptible individuals among both adults and children and probably the introduction of new strains of C. diphtheriae. Vaccine quality, vaccine supply, or access to vaccine providers did not significantly contribute to the epidemic. Mass vaccination of adults and improved childhood immunization controlled the epidemic. High levels of population immunity, especially among children, will be needed to prevent and control similar outbreaks in the future.

Increased protections during a measles outbreak of children previously vaccinated with a second dose of measles-mumps-rubella vaccine

BACKGROUND In 1989 a second dose of measles vaccine was recommended for US children to prevent school outbreaks of measles. Coverage of school age children with a second dose remains incomplete, and data on the effectiveness of this recommendation are limited. We investigated a measles outbreak in Mesa County, CO, in December, 1994, and evaluated the efficacy of preoutbreak immunizations at an elementary school (School A) where many students had received two doses. METHODS All reported suspected cases of measles were investigated; cases that met a clinical case definition were tested by a measles IgM antibody assay. A confirmed case required laboratory confirmation or had to meet the clinical case definition and be epidemiologically linked to a confirmed case. Vaccination records of students at School A were reviewed. The effectiveness of one and two doses of measles vaccine was estimated using logistic regression. RESULTS Sixty-two confirmed cases were reported, including 17 at School A. At School A the attack rate in unvaccinated children (7 of 16, 44%) was higher than in those with 1 dose (10 of 320, 3%) or 2 doses (0 of 289, 0%). Estimated vaccine effectiveness was 92% for 1 dose and 100% for 2 doses. Two doses were better than one dose in decreasing the likelihood of acquiring measles (P = 0.003). CONCLUSIONS The lower attack rate among two dose recipients provides evidence that a two dose strategy can help prevent measles in schools. Administering the second dose at elementary school entry can help prevent the persistence of susceptible cohorts of children and is likely to be important in sustaining elimination of indigenous transmission of measles in the United States.

Discriminators between Hantavirus-Infected and -Uninfected Persons Enrolled in a Trial of Intravenous Ribavirin for Presumptive Hantavirus Pulmonary Syndrome

To provide a potentially therapeutic intervention and to collect clinical and laboratory data during an outbreak of hantavirus pulmonary syndrome (HPS), 140 patients from the United States with suspected HPS were enrolled for investigational intravenous ribavirin treatment. HPS was subsequently laboratory confirmed in 30 persons and not confirmed in 105 persons with adequate specimens. Patients with HPS were significantly more likely than were hantavirus-negative patients to report myalgias from onset of symptoms through hospitalization, nausea at outpatient presentation, and diarrhea and nausea at the time of hospitalization; they were significantly less likely to report respiratory symptoms early in the illness. The groups did not differ with regard to time from the onset of illness to the point at which they sought care; time from onset, hospitalization, or enrollment to death was significantly shorter for patients with HPS. At the time of hospitalization, patients with HPS more commonly had myelocytes, metamyelocytes, or promyelocytes on a peripheral blood smear, and significantly more of them had thrombocytopenia, hemoconcentration, and hypocapnia. Patterns of clinical symptoms, the pace of clinical evolution, and specific clinical laboratory parameters discriminated between these 2 groups.

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. After 30 years of control, epidemic diphtheria, caused by toxigenic strains of Corynebacterium diphtheriae, re-emerged in the early 1990s in the Newly Independent States (NIS) of the former Soviet Union. The epidemic peaked in 1994‐1995 and was on the decline by 1996. This article reviews the diphtheria epidemic in the NIS, the epidemiology of diphtheria in the United States, and the implications of the NIS diphtheria epidemic for prevention of diphtheria in the United States. The Diphtheria Epidemic in the NIS In the late 1950s, universal childhood immunization with diphtheria toxoid was begun throughout the former Soviet Union, and the immunization program successfully controlled diphtheria for almost 30 years. In 1976, reported cases in the Soviet Union fell to !200 (incidence rate, 0.08/100,000 population) [1], compared with 1955, when 1100,000 cases were reported in Russia alone. During the 1970s, most of the reported cases were from the Central Asian Republics. In the mid-1980s, there was a small resurgence of almost 2000 cases per year, mostly in Russia, which was then followed by a decrease to 839 cases in 1989. a Deceased.

Risk of diphtheria among schoolchildren in the Russian Federation in relation to time since last vaccination

BACKGROUND Between 1990 and 1996, more than 110,000 cases and 2900 deaths from diphtheria were reported in the Russian Federation. In 1994, because disease rates were high among children aged 7-10 years, the age of administration of the second booster dose of diphtheria vaccine was lowered from 9 years to 6 years, the age of school entry. To assess the impact of this policy change, we did a matched case-control study in three Russian cities. METHODS Children aged 6-8 years who had diphtheria between September, 1994, and December, 1996, were each matched with five to seven children acting as controls who were within 3 months of age of the case and were from the same class at school. We did a matched analysis using conditional logistic regression. FINDINGS We analysed the immunisation records of 58 cases and 306 controls. All but one case and all controls had received at least three doses of diphtheria-toxoid vaccine. 19 (33%) cases and 144 (47%) controls had received a booster dose of diphtheria toxoid within the previous 2 years. Cases were more likely than were controls to have received only four doses rather than five (odds ratio 2.8 [95% CI 1.2-6.5]) and to have a time since the last dose of diphtheria toxoid of 3-4 years (3.1 [1.1-9.1]) or 5-7 years (15.0 [2.5-89.0]), compared with children for whom it was 2 years or less. On multivariate analysis only a time since the last dose of 5-7 years remained significantly associated with disease (matched odds ratio adjusted for total number of doses 10.9 [1.6-75.1]). CONCLUSION A booster dose of diphtheria-toxoid vaccine given to children in the Russian Federation at 6-8 years of age reduced the interval since the last dose of diphtheria toxoid and improved protection against diphtheria.