An evaluation of computer-aided disproportionality analysis for post-marketing signal detection.

To understand the value of computer-aided disproportionality analysis (DA) in relation to current pharmacovigilance signal detection methods, four products were retrospectively evaluated by applying an empirical Bayes method to Merck's post-marketing safety database. Findings were compared with the prior detection of labeled post-marketing adverse events. Disproportionality ratios (empirical Bayes geometric mean lower 95% bounds for the posterior distribution (EBGM05)) were generated for product-event pairs. Overall (1993-2004 data, EBGM05> or =2, individual terms) results of signal detection using DA compared to standard methods were sensitivity, 31.1%; specificity, 95.3%; and positive predictive value, 19.9%. Using groupings of synonymous labeled terms, sensitivity improved (40.9%). More of the adverse events detected by both methods were detected earlier using DA and grouped (versus individual) terms. With 1939-2004 data, diagnostic properties were similar to those from 1993 to 2004. DA methods using Merck's safety database demonstrate sufficient sensitivity and specificity to be considered for use as an adjunct to conventional signal detection methods.

Ecologic correlates of cancer mortality patterns in an industrialized urban population.

Cancer mortality data for the period 1968-80 were analyzed to examine whether the high cancer burden for the city of Philadelphia was "evenly" distributed spatially and, if not, whether this distribution could be associated with socioeconomic variables and air pollution. Areas with significantly higher-than-expected rates tended to cluster; lung cancer and non-lung cancers showed distinctive cluster patterns, which were evident only for males; female rates for any cancer or groups of cancers were almost uniformly distributed over the neighborhoods. Both the high lung cancer and the high non-lung cancer clusters were characterized by low socioeconomic status, but only the high lung cancer clusters exhibited high levels of air pollution. These neighborhood characteristics suggested that socioeconomic variables explain non-lung cancer mortality patterns; socioeconomic variables, together with air pollution, could be responsible for the observed lung cancer patterns. The uniform distribution of female lung cancer rates suggested that air pollution by itself cannot be a prominent factor in lung cancer mortality.

Postmarketing evaluation of the safety and effectiveness of varicella vaccine.

BACKGROUND: The Oka strain of live attenuated varicella virus was licensed for use in healthy children in the United States in March, 1995. We report a postmarketing evaluation of the short term safety of this vaccine within Kaiser Permanente. METHODS: After licensure varicella vaccination was introduced into the preventive care program of the Northern California Kaiser Permanente Medical Care Program. Potential adverse events after vaccination with varicella vaccine were identified from automated clinical databases of hospitalizations, emergency room visits and clinic visits. Deaths were identified from automated clinical databases at Kaiser as well as from the State death records for California. To evaluate safety, rates of diagnosis-specific events in the risk periods were compared with the rates of such diagnosis-specific events in two self control and one historical control period. RESULTS: During the study period of April 1, 1995, to December 31, 1996, a total of 89753 adults and children received varicella vaccine. A total of 3200 relative risks were calculated, and of these 5 hospital diagnostic categories, 9 emergency visit diagnostic categories and 30 outpatient diagnostic categories demonstrated at least 1 relative risk with a P value of <0.05 in 1 or more age groups and in comparisons with 1 control period or more. The p value for these tests was not adjusted for multiple comparisons. Of these categories 14 demonstrated an increased risk either in more than 1 age group or against more than 1 comparison group. These categories included elective procedures, febrile seizure, febrile illness, well child, acute gastroenteritis, varicella, congenital anomaly, "rule out sepsis," trauma, viral syndrome, apnea, back pain, congenital valvular heart disease and vision evaluation for glasses. Of these the outcomes of elective procedure, congenital anomaly, congenital valvular heart disease, well child and vision evaluation for glasses were judged not to have a biologically plausible association with vaccination. A second diagnostic grouping included febrile illness, viral illness, febrile seizure and "rule out sepsis." In an analysis of these events which adjusted for the concomitant administration of M-M-R(II) vaccine, none of the associations was statistically associated with receipt of varicella vaccine. The diagnostic category of "rule out sepsis" still had a relative risk of 1.95 with P = 0.02. None of the children in the "rule out sepsis" category had positive bacteriologic cultures from any other normally sterile site. Because of the large number of gastroenteritis cases, we reviewed a random sample of 100 exposed and 100 unexposed cases. From this review no consistent time association or clustering of any of these events was seen in the exposed follow-up time interval. Only gastroenteritis and negative evaluations for sepsis were thought to be possibly associated with receipt of varicella vaccine. Although there was a statistically significant increased risk over the entire 30 day-period, there was no clustering of these events within the 30-day window. CONCLUSION: In this study population of 89753 children and adults, the varicella vaccine (Oka strain, Merck) appeared to have a favorable safety profile. In addition rates of varicella-like rash and of breakthrough cases were both low and consistent with the rates observed in prelicensure studies.

Varicella vaccine exposure during pregnancy: data from the first 5 years of the pregnancy registry.

OBJECTIVE: To assess the risks of congenital varicella syndrome and other birth defects in offspring of women who inadvertently received varicella vaccine during pregnancy or within 3 months of conception. METHODS: Pregnant women inadvertently exposed to varicella vaccine, reported voluntarily, were enrolled in the Pregnancy Registry for VARIVAX (Merck & Co., Inc., West Point, PA). The pregnancies were monitored and the outcomes ascertained from questionnaires completed voluntarily by the health care providers. The rates of congenital varicella syndrome and congenital anomalies were calculated for seronegative women prospectively reported to the registry. RESULTS: From March 17, 1995 through March 16, 2000, 362 pregnancy outcomes were identified from prospective reports. Ninety-two women were known to be seronegative to varicella, of whom 58 received their first dose of vaccine during the first or second trimester. No cases of congenital varicella syndrome were identified among 56 live births (rate 0%, 95% confidence interval [CI] 0, 15.6). Among all the prospective reports of live births, five congenital anomalies were reported. No specific pattern was identified in either the susceptible cohort or the sample population as a whole. CONCLUSION: No abnormal features have been reported that suggested the occurrence of congenital varicella syndrome or other birth defects related to vaccine exposure during pregnancy. Because of the small numbers, this study has limited precision, so continued surveillance is warranted. However, these results should provide some assurance to health care providers and women with inadvertent exposure before or during pregnancy.

Evaluation of two rapid methods for the detection of herpes simplex virus antigen in patient specimens.

An indirect immunofluorescent antibody procedure (IFA) for the detection and typing of herpes simplex virus (HSV) and an enzyme-linked immunosorbent assay (ELISA) procedure were compared with conventional viral culture. Specimens for culture and ELISA were inoculated into serum free viral transport medium (VTM) and, for IFA, onto slides provided in the kit. Tissue cultures (MRC-5 and primary rabbit kidney) were inoculated and examined daily for cytopathogenic effect (CPE). The remaining VTM was frozen at -70 degrees C until tested by the ELISA system. Slides for IFA were stained with HSV common and HSV-2 specific monoclonal antibodies. Of 155 specimens, 47 (30 percent) were unsatisfactory for the IFA test owing to an inadequate number of epithelial cells on the slides. Of 108 adequate specimens, 45 were culture positive; 39 were positive by the IFA test with a sensitivity of 87 percent and a specificity of 90 percent. Of the 39 positives, 29 (75 percent) were correctly classified as type 1 or type 2, six (15 percent) were typed incorrectly, and four (10 percent) were inadequate for typing by the IFA test. All 155 specimens were suitable for testing by the ELISA procedure. Of 55 specimens positive by culture, only 25 (sensitivity 45 percent) were positive by ELISA. However, the specificity was 100 percent. After incubation of two, three, and six days, the tissue cultures detected 71 percent, 89 percent, and 100 percent of the positives, respectively.

National influenza experience in the USA, 1968-69.

An extensive outbreak of Hong Kong influenza occurred in the USA during the autumn and early winter of 1968-69. Introduction and seeding of the virus occurred in September and early October as individuals returned from the Far East. Civilian outbreaks did not develop until late October and November. By 28 December, all States had experienced influenza outbreaks. Limited information concerning age- and sex-specific attack rates indicates that all age segments of the population were equally involved. Significant excess pneumonia-influenza mortality occurred in all 9 geographical areas of the country and followed influenza activity by several weeks. Influenza B activity was documented in 37 States during the winter.

Risk factors for syphilis: cocaine use and prostitution.

In Philadelphia, a large increase in syphilis among minority group heterosexuals began in 1986 and preceded similar increases elsewhere in the United States. To determine reasons for this increase, we conducted a case-control study in the metropolitan sexually transmitted diseases clinic during 1987 and 1988. Cocaine use (odds ratio [OR] 3.1; 95% confidence interval [95% CI] = 1.5, 6.5 among men; OR 5.8; 95% CI = 1.5, 33 among women) and exchange of drugs for sex (OR 3.5; 95% CI = 1.4, 8.7 among men) were risk factors for syphilis. Although cocaine users reported more sexual partners and more frequently reported sex with prostitutes, cocaine use remained a risk factor after adjustment for these behaviors. These data suggest that sexual behavior or another factor, such as availability or utilization of health care, among cocaine users leads to increased risk of syphilis in this population. Increases in cocaine use may be partly responsible for recent increases in syphilis incidence in the United States.

Passive smoking in obstructive respiratory disease in an industrialized urban population.

We examined the risk of obstructive respiratory disease associated with tobacco smoke in indoor air, independent of active smoking, ambient air pollution, and some of the other sources of residential indoor air pollution. Data came from a probability sample survey of nine neighborhoods in Philadelphia conducted in 1985-1986, leading to information on approximately 4200 individuals. While for never-smokers the prevalence of obstructive respiratory conditions was proportional to the level of environmental tobacco smoke, this second-hand smoke was not a factor in the frequency of such problems among current smokers. In a series of analyses restricted to never-smokers, each of the 219 index cases of obstructive respiratory disease was matched by age, gender, and neighborhood to three randomly selected controls where matching by neighborhood effectively controlled for ambient air pollution. Both matched and unmatched two-sample analyses showed a statistically significant difference (P = 0.019 and 0.016, respectively) between cases and controls with respect to the level of tobacco smoke in the indoor environment. A conditional logistic regression-matched analysis revealed that heating and cooking as sources of indoor air pollution were not associated with the case/control status. However, the odds ratio for passive smoking at a level of more than one pack per day in the house environment was 1.86 (95% CI, 1.21-2.86). The results show that passive smoking is a significant risk factor for obstructive respiratory disease for never-smokers in an industrialized urban population.

Characterization of yeast agglutinins in lavage fluid from lungs of rabbits.

Rabbits were challenged intratracheally with 10(8) Candida albicans or Torulopsis glabrata, and their lungs were lavaged 5, 60, and 120 min later. Initial lavage samples showed significant agglutination of yeasts, followed by the development of larger aggregates in association with alveolar macrophages. To investigate this early agglutination reaction, lungs of normal rabbits were lavaged with heparinized saline, and after alveolar macrophages were discarded, the cell-free lavage fluid was centrifuged at 25,000 g to recover a small, whitish, surface-active pellet (F fraction). The supernatant was concentrated 15-fold by vacuum dialysis (P fraction). When Candida species, T. glabrata, and Saccharomyces cerevisiae were incubated with the F fraction, serial colony counts decreased eight- to 20-fold with every yeast species tested except S. cerevisiae and Candida krusei. Decrease in colony counts was associated with yeast agglutination. The F fraction was further separated by ethanol-ether extraction, and yeast agglutination was seen only in the protein-rich fraction. Further separation of this protein-rich fraction by polyacrylamide gel electrophoresis yielded three bands, one of which, with a molecular size of about 10(4) daltons, agglutinated C. albicans. IgA in the P fraction also agglutinated C. albicans, although not as dramatically as the F fraction.

Patterns of mortality from selected causes in an urban population.

Mortality data for selected non-cancer causes for the period 1974-1980 were analyzed for the City of Philadelphia to examine spatial patterns. Four categories of conditions--ischemic heart disease (including acute myocardial infarction), chronic liver disease and cirrhosis, cerebrovascular disease, and external causes--demonstrated significant variation in death rates. Moreover, neighborhoods with high levels of mortality for these conditions appeared in significant clusters. With the exception of ischemic heart disease, neighborhoods with high levels of mortality were characterized by below average levels of SES. A group of predominantly black neighborhoods in the central part of the city had extremely high rates for five or more of the nine causes investigated in this paper. In an earlier analysis, all but one of these neighborhoods were found to have the highest level of overall cancer mortality. These findings support the hypothesis that there are social and behavioral factors that are associated with a wide range of disease conditions, and many of these factors are associated with socioeconomic status.

Transmission of varicella-vaccine virus from a healthy 12-month-old child to his pregnant mother.

A 12-month-old healthy boy had approximately 30 vesicular skin lesions 24 days after receiving varicella vaccine. Sixteen days later his pregnant mother had 100 lesions. Varicella-vaccine virus was identified by polymerase chain reaction in the vesicular lesions of the mother. After an elective abortion, no virus was detected in the fetal tissue. This case documents transmission of varicella-vaccine virus from a healthy 12-month-old infant to his pregnant mother.

Comparison of media for direct isolation and transport of Shigellae from Fecal specimens.

Xylose-lysine-deoxycholate (XLD) agar, SS agar, and MacConkey agar for isolating shigellae from fecal specimens were compared. XLD agar was superior to both SS agar and MacConkey agar for isolating Shigella sonnei, and both XLD and SS agar were superior to MacConkey agar for isolating S. flexneri. Direct plating of the fecal specimens in the field resulted in a greater yield of shigellae as compared to transporting specimens to the laboratory either in holding media or enrichment broth. Buffered glycerol saline was superior to other transport media evaluated, yielding 83% of shigella isolates when plated within 48 hr as compared to direct plating. The combination of XLD agar and SS agar is recommended for direct isolation of shigellae, and, whenever possible, these solid media should be taken to the bedside and inoculated directly.

Summertime pneumonias in Philadelphia in 1976. An epidemiologic study.

Summertime pneumonias in Philadelphia during 1976 were studied epidemiologically, and the epidemiologic, clinical, and laboratory features of pneumonia cases serologically positive for Legionnaires' disease were compared with features of serologically negative cases. Both groups were similar in many respects, but in patients with Legionnaires' disease diarrhea and neurologic findings were significantly more frequent (P = 0.01 and P = 0.05 respectively). A diagnosis of Legionnaires' disease was also suggested by an elevated serum creatinine phosphokinase level (P = 0.02) and the presence of occult blood in the urine with fewer than six erythrocytes per highpower field. Abnormalities in renal function tests or liver function tests were commoner in patients with Legionnaires' disease (P = 0.05). Radiographic features, however, could not be used to separate pneumonia cases. The high frequency of extrapulmonary manifestations involving the gastrointestinal tract, the central nervous system, kidneys, and liver suggests that Legionnaires' disease is a multisystemic disorder possibly caused by a toxin-producing organism.

Isoniazid prophylaxis in hepatitis B carriers.

Both tuberculosis and hepatitis B are endemic in southeast Asia and are common among refugees to the United States from that region. Isoniazid, used for the prophylactic treatment of tuberculosis, is a potentially hepatotoxic drug. Carriers of the hepatitis B virus are likely to have some degree of liver damage due to their chronic infection. We hypothesized that prophylactic treatment of carriers with isoniazid would cause greater liver damage, as measured by serum alanine aminotransferase (ALT) levels, than would such therapy of noncarriers. Cross-sectional and longitudinal studies of the southeast Asian refugee population in Philadelphia failed to support this hypothesis. Isoniazid did not cause greater hepatotoxicity in hepatitis B carriers than in noncarriers. Although carriers had higher ALT levels than noncarriers, both groups experienced transient ALT elevations during the first 2 months of isoniazid prophylactic therapy. Therefore, we concluded that chronic infection with hepatitis B virus is not a contraindication to the prophylactic use of isoniazid.

Legionnaires' disease: description of an epidemic of pneumonia.

An explosive, common-source outbreak of pneumonia caused by a previously unrecognized bacterium affected primarily persons attending an American Legion convention in Philadelphia in July, 1976. Twenty-nine of 182 cases were fatal. Spread of the bacterium appeared to be air borne. The source of the bacterium was not found, but epidemiologic analysis suggested that exposure may have occurred in the lobby of the headquarters hotel or in the area immediately surrounding the hotel. Person-to-person spread seemed not to have occurred. Many hotel employees appeared to be immune, suggesting that the agent may have been present in the vicinity, perhaps intermittently, for two or more years.

The postmarketing safety profile of varicella vaccine.

The postmarketing safety profile of varicella vaccine was evaluated by analyzing selected adverse experience reports temporally associated with the administration of the vaccine. There were 7963 reports voluntarily submitted to Merck for an overall reporting rate of 5.0 per 10000 doses of vaccine distributed. A varicella zoster virus (VZV) identification program detected the presence of the Oka vaccine strain in three individuals with an immune deficiency - two with pneumonia and one with hepatitis - and in three instances of secondary transmission from vaccinees with vesicular lesions to susceptible household contacts. The Oka vaccine strain was present in 23 patients and wild-type VZV was present in 15 patients with herpes zoster. Vesicular rashes that occurred within 2 weeks of vaccination were more likely to contain the presence of wild-type VZV, while vesicular rashes that occurred more than 2 weeks post-vaccination were more likely to contain the Oka vaccine strain. Eleven patients were hospitalized with complications of breakthrough varicella infection.