Active Surveillance Project Research Articles

Response to Letter to the Editor by JumaanGoldman’s role in the Varicella Active Surveillance Project

Response to Letter to the Editor by JumaanGoldman’s role in the Varicella Active Surveillance Project

Contagiousness of varicella in vaccinated cases: a household contact study.

Limited data are available on the contagiousness of vaccinated varicella cases. To describe secondary attack rates within households according to disease history and vaccination status of the primary case and household contacts and to estimate varicella vaccine effectiveness. Population-based, active varicella surveillance project in a community of approximately 320,000 in Los Angeles County, California, during 1997 and 2001. Varicella cases were reported by child care centers, private and public schools, and health care clinicians and were investigated to collect demographic, clinical, medical, and vaccination data. Information on household contacts' age, varicella history, and vaccination status was collected. Varicella secondary attack rate among household contacts; vaccine effectiveness using secondary attack rates in unvaccinated and vaccinated children and adolescents. A total of 6316 varicella cases were reported. Among children and adolescents aged 1 to 14 years, secondary attack rates varied according to age and by disease and vaccination status of the primary case and exposed household contacts. Among contacts aged 1 to 14 years exposed to unvaccinated cases, the secondary attack rate was 71.5% if they were unvaccinated and 15.1% if they were vaccinated (risk ratio [RR], 0.21; 95% confidence interval [CI], 0.15-0.30). Overall, vaccinated cases were half as contagious as unvaccinated cases. However, vaccinated cases with 50 lesions or more were similarly contagious as unvaccinated cases whereas those with fewer than 50 lesions were only one third as contagious (secondary attack rate, 23.4%; RR, 0.32 [95% CI, 0.19-0.53]). Vaccine effectiveness for prevention of all disease was 78.9% (95% CI, 69.7%-85.3%); moderate disease, 92% (50-500 lesions) and 100% (clinician visit); and severe disease, 100%. Under conditions of intense exposure, varicella vaccine was highly effective in preventing moderate and severe disease and about 80% effective in preventing all disease. Breakthrough varicella cases in household settings were half as contagious as unvaccinated persons with varicella, although contagiousness varied with numbers of lesions.

Using capture–recapture methods to assess varicella incidence in a community under active surveillance

The Varicella (chickenpox) Active Surveillance Project (VASP) has been conducting active surveillance since 1 January 1995 in the high desert community known as Antelope Valley, CA (population 300,000) among 300 public and private schools, daycares, and healthcare providers. Capture–recapture methods were applied to estimate reporting completeness for 1995 varicella incidence data and these were compared with the national average incidence rates by age reported by the National Health Interview Survey (NHIS). Varicella cases reported among individuals aged <20 years reflect under-reporting in excess of 50%. Despite limitations on accuracy, capture–recapture estimates are a reasonably accurate, quick, and inexpensive approach in epidemiologic studies.

Work-related injuries in residential and drywall carpentry.

Findings are reported on the first two years of an active injury surveillance project designed to test the utility of active injury investigations in identifying causes of injury among a large cohort of carpenters who did residential building and drywall installation. Occupational Safety and Health Administration recordable injuries were reported by participating contractors. Injured union carpenters were interviewed by experienced journeymen trained in a standard questionnaire protocol. Enumeration of workers and hours worked were provided by the union. These data allowed the definition of a dynamic cohort of 4429 carpenters, their hours worked, detailed information on the circumstances surrounding recordable injuries, and possible preventive measures from the perspectives of the injured worker and an experienced journeyman investigator. The overall estimated injury rate (16.9 per 200,000 hours worked) was considerably higher than recent Bureau of Labor Statistics rates despite less than complete ascertainment of injuries. Injuries most commonly involved being struck by or against something, manual materials handling injuries, and falls. Manual materials handling injuries often involved very heavy objects or tasks and were injuries carpenters most often reported needs for adequate help and coordinated team work to prevent. Falls from heights occurred from a variety of surfaces and were not just injuries of inexperience. Carpenters reported the need for more attention to common fall protection practices, such as the use of more toe boards and guardrails. Poor housekeeping was involved in the majority of same level falls, as well as some manual materials handling injuries.

Perinatal Listeriosis

The aim off this study was to describe the incidence, epidemiology, clinical presentation, and outcome of perinatal listeriosis for a 7-year period (1990-1996) based on data of an active population-based surveillance project implemented in the city of Barcelona, Spain. There were 30 cases (20.8%) associated with pregnancy (15 pregnant women, 13 neonates, and 2 fetal deaths). The incidence of perinatal listeriosis varied from 4.1 to 0 per 10,000 live births. The proportion of perinatal cases in relation to the total number of cases of listeriosis varied between 0 and 42%. Early-onset neonatal sepsis accounted for 12 of 13 live births. The mean age of infected pregnant women with listeriosis was 30.1+/-2.0 years. Chorioamnionitis was the predominant clinical form (86.7%). Only two mothers had primary bacteremia by L. monocytogenes in the second trimester of pregnancy. Both infants were born healthy, without signs of infection. One of these mothers was infected with the human immunodeficiency virus (HIV). Since January 1994, 12 strains were available for serotyping and phagotyping; 9 belonged to serovar 4b, 2 to serovar 1/2b, and 1 to serovar 1/2a. No outbreaks of L. monocytogenes infection occurred during the study period. The overall neonatal mortality rate was 7.7% among infected live births. All pregnant women were treated with ampicillin and none died. Early antenatal treatment with ampicillin improves neonatal outcome and can result in the birth of healthy babies.

Maternal cigarette smoking and invasive meningococcal disease: a cohort study among young children in metropolitan Atlanta, 1989-1996.

This study assessed the association between maternal cigarette smoking during pregnancy and the risk of invasive meningococcal disease during early childhood. Using a retrospective cohort study design, cases from an active surveillance project monitoring all invasive meningococcal disease in the metropolitan Atlanta area from 1989 to 1995 were merged with linked birth and death certificate data files. Children who had not died or acquired meningococcal disease were assumed to be alive and free of the illness. The Cox proportional hazards analysis was used to assess the independent association between maternal smoking and meningococcal disease. The crude rate of meningococcal disease was 5 times higher for children whose mothers smoked during pregnancy than for children whose mothers did not smoke (0.05% vs 0.01%). Multivariate analysis revealed that maternal smoking (risk ratio [RR] = 2.9; 95% confidence interval [CI] = 1.5, 5.7) and a mother's having fewer than 12 years of education (RR = 2.1; 95% CI = 1.0, 4.2) were independently associated with invasive meningococcal disease. Maternal smoking, a likely surrogate for tobacco smoke exposure following delivery, appears to be a modifiable risk factor for sporadic meningococcal disease in young children.

Occupational Agricultural Injury Surveillance in California

SUMMARY The objective of the California Nurses Using Rural Sentinel Events (NURSE) is to prevent occupational agricultural injuries. This active surveillance and health education project obtains incident reports of injuries from sources in two California counties. Over 5000 of these reports are in a database, coded by cause and na-ture of injury using the International Classification of Dis-eases- 9-CM. From these, 35 illustrative incidents have been investi-gated and summarized in widely disseminated prevention strategy reports. Health and safety education outreach is provided by bi-lin-gual field staff several times monthly. The NURSE project has de-veloped valuable database and educational resources for research and promotion of safety in agriculture.

Safety of cyproterone acetate: report of active surveillance.

Concern about a potentially increased risk of liver cancer associated to cyproterone acetate (CPA) treatment led to a postmarketing long-term surveillance study with historic accural of four groups of patients with sexual-hormonal disorders under treatment with CPA. The aim of the study was to provide a description of potential ADRs under CPA treatment with special emphasis on liver cancer. A long-term follow-up of 2506 patients was conducted. Six hundred and two persons were followed up retrospectively for longer than 10 years. In 16,721 patient-years of observation after the first CPA dose no malignant liver tumour was observed, whereas six would have been expected in this cohort. Seven incident, non-fatal benign liver tumours were found. Altogether 9.6% of a subset of 1685 patients with reported liver tests had, at some time, elevated liver enzymes. No cases were reported where CPA therapy had been discontinued due to severe liver disorder. We concluded from this active surveillance project, that CPA treatment is probably safe in the groups of patients followed up. Even though there was not a single case of liver cancer detected, the hypothesis of an elevated risk is being tested in an ongoing collaborative European case-control study which is examining the association of CPA use and primary hepatocellular cancer.

Safety of Cyproterone Acetate: Report of Active Surveillance

Concern about a potentially increased risk of liver cancer associated to cyproterone acetate (CPA) treatment led to a postmarketing long-term surveillance study with historic accural of four groups of patients with sexual-hormonal disorders under treatment with CPA. The aim of the study was to provide a description of potential ADRs under CPA treatment with special emphasis on liver cancer. A long-term follow-up of 2506 patients was conducted. Six hundred and two persons were followed up retrospectively for longer than 10 years. In 16,721 patient-years of observation after the first CPA dose no malignant liver tumour was observed, whereas six would have been expected in this cohort. Seven incident, non-fatal benign liver tumours were found. Altogether 9.6% of a subset of 1685 patients with reported liver tests had, at some time, elevated liver enzymes. No cases were reported where CPA therapy had been discontinued due to severe liver disorder. We concluded from this active surveillance project, that CPA treatment is probably safe in the groups of patients followed up. Even though there was not a single case of liver cancer detected, the hypothesis of an elevated risk is being tested in an ongoing collaborative European case–control study which is examining the association of CPA use and primary hepatocellular cancer. © John Wiley & Sons, Ltd.

Perinatally acquired human immunodeficiency virus infection

To evaluate factors that may affect the timely diagnosis of children with human immunodeficiency virus (HIV) infection, we compared data derived from two population-based pediatric HIV studies. Data from anonymous newborn HIV serosurveys were used to estimate the number of children born to HIV-seropositive mothers. A statewide active surveillance project determined the number of HIV-exposed children who had been clinically recognized. Of 88,732 Massachusetts newborn specimens tested anonymously for HIV antibodies during a 12-month period (November, 1987, to October, 1988), 223 were positive. As of October, 1991, 78 of these children (35%) had been identified by a statewide network of infectious disease physicians. HIV-exposed children born in inner city hospitals were more likely to have come to medical attention than those born in suburban hospitals (47% vs. 17%). Among the 29 children with confirmed HIV infection (13% of 223), the initial evaluation for HIV occurred at an earlier age among children born in inner city hospitals than among children born in other areas. HIV testing practices that rely heavily on risk assessment may result in delayed diagnosis of HIV infection in children whose mothers are not perceived to be at risk.

Comparison of cold enrichment and U.S. Department of Agriculture methods for isolating Listeria monocytogenes from naturally contaminated foods. The Listeria Study Group

We compared the cold enrichment (CE) and U.S. Department of Agriculture (USDA) methods for isolating Listeria monocytogenes by examining 402 food samples. The food samples were collected from refrigerators of listeriosis patients as part of a multistate active surveillance project to determine the role of foods in sporadic listeriosis in the United States. L. monocytogenes was isolated from 51 food samples (13%). The USDA method was significantly better (P less than 0.001) than the CE method. The isolation efficiencies of the USDA and CE methods were 96 and 59%, respectively. Quantitation of L. monocytogenes in the food samples revealed that many food samples containing less than 0.3 CFU/g were negative as determined by the CE method but positive as determined by the USDA method.

The Epidemiology of Listeriosis in the United States—1986

To determine the morbidity and mortality due to listeriosis in the United States, the authors undertook an active surveillance project in 1986 to identify all cases in which Listeria monocytogenes was isolated from cultures of ordinarily sterile sites in a population of 34 million persons. The authors estimated that at least 1,700 cases of listeriosis and 450 deaths occurred in the United States in 1986; 27% of these cases occurred in pregnant women, with 22% of perinatal cases resulting in stillbirths or neonatal deaths. The risk of listeriosis in adults (0.5 per 100,000 population) was similar in all regions studied; the incidence of perinatal listeriosis was three times higher in Los Angeles County, California, than in the other areas (24.3/100,000 live births vs. 7.8/100,000 live births). Geographic variation may have resulted from underdiagnosis of perinatal listeriosis in five of the study areas. Multilocus electrophoretic enzyme typing was useful for elucidating the molecular epidemiology of L. monocytogenes; perinatal listeriosis was significantly associated with one group of related strains. Multilocus electrophoretic enzyme typing also identified three clusters representing possible common-source outbreaks. These findings document the substantial morbidity due to listeriosis in the United States; to the extent that sporadic listeriosis is foodborne, this morbidity could be reduced by appropriate preventive measures, particularly in persons known to be at increased risk of infection.