American journal of epidemiology
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Since January, 1970, the Center for Disease Control (CDC) has corridnated surveillance of nosocomial infections in a group of voluntarily cooperating hispitals in the United States. In 1970, this surveillance system failed to realize one of its major goals: detection of a nationwide epidemic of septicemia caused by contaminated intravenous products. However, retrospective review of infections reported to CDC revealed that the data received were sufficient for the outbreak to have been recognized. ⋯ Furthermore, monthly rates of cases of bacteremia caused by these organisms were higher in hospitals using the contaminated intravenous products than for hospitals not using them. Failure to detect this outbreak at the time of its occurrence was due to delays in data processing and insufficiently sophisticated data analysis. Based on this experience, CDC has modified the surveillance system to aid recognition of future outbreaks.
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The hypothesis that spontaneous abortion is associated with prior induced abortion is tested in an epidemiologic study. The reproductive histories of a consecutive series of women admitted to hospital with spontaneous abortions were compared with those of a control series of women who delivered after 28 weeks gestation. ⋯ The power of the analysis to detect a 30% excess in the frequency of induced abortion in cases as compared to controls is 82% at alpha = .05. The design and analysis effectually controlled for all potentially confounding factors.
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After a sharp increase in viral hepatitis cases, mostly type B, among the 2000 employees of a general hospital during three years, we conducted an investigation which consisted of obtaining data on employee cases and surveying many current employees. Of the 38 cases, 22 occurred in non-physician, ward employees. Of 189 current ward employees, 8% had antibody to hepatitis B surface antigen (anti-HBS) and 1% had hepatitis B surface antigen (HBSAg). ⋯ HBV seropositivity was highest for those working in the chemistry section (highest there among those performing blood-gas determinations and those working with the multi-channel autoanalyzers) and those who routinely got blood on their skin and clothes at work. All seropositive employees worked routinely with blood. These data support the hypotheses that many hospital employees contract hepatitis B from exposure to HBSAg-positive patients and many clinical laboratory employees contract it from exposure to HBV-contaminated blood.