Traditional fecal indicators currently used to monitor these beaches were not associated with health risks. These results suggest a need for alternative indicators of water quality where nonpoint sources are dominant fecal contributors.

Trials have provided conflicting estimates of the risk of gastrointestinal illness attributable to tap water. To estimate this risk in an Iowa community with a well-run water utility with microbiologically challenged source water, the authors of this 2000-2002 study randomly assigned blinded volunteers to use externally identical devices (active device: 227 households with 646 persons; sham device: 229 households with 650 persons) for 6 months (cycle A). Each group then switched to the opposite device for 6 months (cycle B). The active device contained a 1-microm absolute ceramic filter and used ultraviolet light. Episodes of "highly credible gastrointestinal illness," a published measure of diarrhea, nausea, vomiting, and abdominal cramps, were recorded. Water usage was recorded with personal diaries and an electronic totalizer. The numbers of episodes in cycle A among the active and sham device groups were 707 and 672, respectively; in cycle B, the numbers of episodes were 516 and 476, respectively. In a log-linear generalized estimating equations model using intention-to-treat analysis, the relative rate of highly credible gastrointestinal illness (sham vs. active) for the entire trial was 0.98 (95% confidence interval: 0.86, 1.10). No reduction in gastrointestinal illness was detected after in-home use of a device designed to be highly effective in removing microorganisms from water.

Objectives. We implemented active surveillance for Guillain–Barré syndrome (GBS) following seasonal or H1N1 influenza vaccination among the Medicare population during the 2009-2010 influenza season. Methods. We used weekly Medicare claims data to monitor vaccinations and subsequent hospitalizations with principal diagnosis code for GBS within 42 days. Group sequential testing assessed whether the observed GBS rate exceeded a critical limit based on the expected rate from 5 previous years adjusted for claims delay. We evaluated the lag between date of service and date of claims availability and used it for adjustment. Results. By July 30, 2010 (after 26 interim surveillance tests), 14.0 million seasonal and 3.3 million H1N1 vaccinations had accrued. Taking into account claims delay appropriately lowered the critical limit during early monitoring. The observed GBS rate was below the critical limit throughout the surveillance. Conclusions. Medicare data contributed rapid safety monitoring among millions of 2009–2010 influenza vaccine recipients. Adjustment for claims delay facilitates early detection of potential safety issues. Although limited by lack of medical record review to confirm cases, this claims-based surveillance did not indicate a statistically significant elevated GBS rate following seasonal or H1N1 influenza vaccination.

PurposeTo develop the infrastructure to conduct timely active surveillance for safety of influenza vaccines and other medical countermeasures in the Sentinel System (formerly the Mini‐Sentinel Pilot), a Food and Drug Administration‐sponsored national surveillance system that typically relies on data that are mature, settled, and updated quarterly.MethodsThree Data Partners provided their earliest available (“fresh”) cumulative claims data on influenza vaccination and health outcomes 3–4 times on a staggered basis during the 2013–2014 influenza season, collectively producing 10 data updates. We monitored anaphylaxis in the entire population using a cohort design and seizures in children ≤4 years of age using both a self‐controlled risk interval design (primary) and a cohort design (secondary). After each data update, we conducted sequential analysis for inactivated (IIV) and live (LAIV) influenza vaccines using the Maximized Sequential Probability Ratio Test, adjusting for data‐lag.ResultsMost of the 10 sequential analyses were conducted within 6 weeks of the last care‐date in the cumulative dataset. A total of 6 682 336 doses of IIV and 782 125 doses of LAIV were captured. The primary analyses did not identify any statistical signals following IIV or LAIV. In secondary analysis, the risk of seizures was higher following concomitant IIV and PCV13 than historically after IIV in 6‐ to 23‐month‐olds (relative risk = 2.7), which requires further investigation.ConclusionsThe Sentinel System can implement a sequential analysis system that uses fresh data for medical product safety surveillance. Active surveillance using sequential analysis of fresh data holds promise for detecting clinically significant health risks early. Limitations of employing fresh data for surveillance include cost and the need for careful scrutiny of signals. © 2015 The Authors. Pharmacoepidemiology and Drug Safety Published by John Wiley & Sons Ltd.

Given the increased risk of Guillain-Barré Syndrome (GBS) found with the 1976 swine influenza vaccine, both active surveillance and end-of-season analyses on chart-confirmed cases were performed across multiple US vaccine safety monitoring systems, including the Medicare system, to evaluate the association of GBS after 2009 monovalent H1N1 influenza vaccination. Medically reviewed cases consisted of H1N1-vaccinated Medicare beneficiaries who were hospitalized for GBS. These cases were then classified by using Brighton Collaboration diagnostic criteria. Thirty-one persons had Brighton level 1, 2, or 3 GBS or Fisher Syndrome, with symptom onset 1-119 days after vaccination. Self-controlled risk interval analyses estimated GBS risk within the 6-week period immediately following H1N1 vaccination compared with a later control period, with additional adjustment for seasonality. Our results showed an elevated risk of GBS with 2009 monovalent H1N1 vaccination (incidence rate ratio = 2.41, 95% confidence interval: 1.14, 5.11; attributable risk = 2.84 per million doses administered, 95% confidence interval: 0.21, 5.48). This observed risk was slightly higher than that seen with previous seasonal influenza vaccines; however, additional results that used a stricter case definition (Brighton level 1 or 2) were not statistically significant, and our ability to account for preceding respiratory/gastrointestinal illness was limited. Furthermore, the observed risk was substantially lower than that seen with the 1976 swine influenza vaccine.

This developed tool was able to elucidate novel utilization and switching patterns in two case studies. Such information can be used to support surveillance of generic drugs and biosimilars.

Our study emphasizes that Cryptosporidium infections are common in this population. Although HIV status altered the risk of Cryptosporidium infection, further studies are needed to adequately examine the effect of CD4 cell count.

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