To assess the validity of Antigen rapid diagnostic tests (Ag-RDT) for SARS-CoV-2 as decision support tool in various hospital-based clinical settings.

Retrospective cohort study among symptomatic and asymptomatic patients and Healthcare workers (HCW).

A large tertiary teaching medical center serving as a major COVID-19 hospitalizing facility.

Ag-RDTs’ performance was assessed in three clinical settings: 1. Symptomatic patients and HCW presenting at the Emergency Departments 2. Asymptomatic patients screened upon hospitalization 3. HCW of all sectors tested at the HCW clinic following exposure.

We obtained 5172 samples from 4595 individuals, who had both Ag-RDT and quantitative real-time PCR (qRT-PCR) results available. Of these, 485 samples were positive by qRT-PCR. The positive percent agreement (PPA) of Ag-RDT was greater for lower cycle threshold (Ct) values, reaching 93% in cases where Ct-value was <25 and 85% where Ct-value was <30. PPA was similar between symptomatic and asymptomatic individuals. We observed a significant correlation between Ct-value and time from infection onset (p<0.001).

Ag-RDT are highly sensitive to the infectious stage of COVID-19 manifested by either high viral load (lower Ct) or proximity to infection, whether patient is symptomatic or asymptomatic. Thus, this simple-to-use and inexpensive detection method can be used as a decision support tool in various in-hospital clinical settings, assisting patient flow and maintaining sufficient hospital staffing.

To assess infection control practices and risk for human immunodeficiency virus (HIV) transmission in households where home infusion for hemophilia is used.

Cross-sectional prospective survey from 1992 through 1994.

Hemophilia treatment centers.

Human immunodeficiency virus (HIV)-infected persons with hemophilia who receive home infusions of clotting factor concentrate and their household members.

Frequency of specific infection control practices in the home and the risk of HIV transmission to household members.

We surveyed 235 persons from 75 families (79 HIV-infected persons with hemophilia and 156 household members) about infection control practices in the home. Forty-eight percent of household members surveyed helped with the infusion process. Of 74 members who assisted with infusion, 13 (18%) had sustained a needlestick injury, 11 of whom were injured during the past year. One hundred fifty household members tested for antibody to HIV were antibody negative. These household members had a total of 903 person-years of contact after HIV was diagnosed in the index case. Household members' adherence to recommended infection control measures was highest for washing hands after cleaning up infusion equipment and waste, and for using sharps disposal containers. Adherence was lowest for wearing gloves when helping with infusions and proper disposal of bloody waste from the infusion.

No HIV transmission was found among persons living with HIV-infected persons with hemophilia, although there was a high rate of needlestick injuries during home infusion. Because persons who assisted with infusions often did not wear gloves and many households did not dispose of bloody waste properly, hemophilia treatment center personnel should emphasize these areas when training for home infusion. Adherence to appropriate infection control practices should help to keep the risk of HIV transmission in households extremely low.

To date, it has not been adequately proven whether the published formulas used to obtain incidence from the prevalence of nosocomial infections provide a good estimate of real incidence. With the hypothesis that within the hospital setting prevalence may be lower than incidence, the aim of this study was to analyze the behavior of point prevalence as it relates to cumulative incidence and duration of infection.

Hospital simulation study.

By randomly selecting a sample of infected patients within a specific range of cumulative incidences and infection durations, we constructed a simulated hospital population, allowing us to estimate daily point prevalences and their maximum and minimum values. The association between the different components of stay and cumulative incidence was evaluated to obtain a more accurate estimate of incidence.

Prevalence can be lower than, equal to, or higher than the corresponding incidence. For all incidence levels, prevalence was increasing with duration. Between 14 and 20 days of infection duration, prevalence was consistently lower than incidence. Prevalence duration of infection was approximately half the time of the total duration.

The existing formulas relating incidence and prevalence can frequently be inadequate. Until a validated system for converting prevalence into incidence is available, we do not believe their use is appropriate.

To determine whether footwear exchange affects the incidence of febrile neutropenia among patients undergoing chemotherapy for hematologic malignancies.

Open trial with historical comparison.

The 12-bed high-efficiency particulate air-fil-tered hematology unit at Osaka University Hospital, Suita, Japan.

Those with hematologic malignancies who underwent chemotherapy from January 1997 through January 2003. Footwear exchange was discontinued in January 2000.

The surveillance system was based on the National Nosocomial Infections Surveillance System of the Centers for Disease Control and Prevention. Rates of febrile neutropenia were calculated for neutropenic patient-days (ie, days with neutropenia < 500/μL).

From January 1997 through December 1999 and from February 2000 through January 2003, 58 and 54 patients endured 237 and 184 neutropenic periods following chemotherapy, and their total neutropenic days were 3,123 and 2,503, respectively. They showed episodes of febrile neutropenia 89 and 68 times, respectively. Infection rates were 28.5 and 27.2 per 1,000 neutropenic patient-days (P = .83), respectively.

The incidence of febrile neutropenia was not affected by footwear exchange. In hematology units, changing shoes does not appear to affect the rate of infections during neutropenic periods.

To determine whether Clostridioides difficile infection (CDI) exhibits spatiotemporal interaction and clustering.

Retrospective observational study.

The University of Iowa Hospitals and Clinics.

This study included 1,963 CDI cases, January 2005 through December 2011.

We extracted location and time information for each case and ran the Knox, Mantel, and mean and maximum component size tests for time thresholds (T = 7, 14, and 21 days) and distance thresholds (D = 2, 3, 4, and 5 units; 1 unit = 5–6 m). All tests were implemented using Monte Carlo simulations, and random CDI cases were constructed by randomly permuting times of CDI cases 20,000 times. As a counterfactual, we repeated all tests on 790 aspiration pneumonia cases because aspiration pneumonia is a complication without environmental factors.

Results from the Knox test and mean component size test rejected the null hypothesis of no spatiotemporal interaction (P < .0001), for all values of T and D. Results from the Mantel test also rejected the hypothesis of no spatiotemporal interaction (P < .0003). The same tests showed no such effects for aspiration pneumonia. Our results from the maximum component size tests showed similar trends, but they were not consistently significant, possibly because CDI outbreaks attributable to the environment were relatively small.

Our results clearly show spatiotemporal interaction and clustering among CDI cases and none whatsoever for aspiration pneumonia cases. These results strongly suggest that environmental factors play a role in the onset of some CDI cases. However, our results are not inconsistent with the possibility that many genetically unrelated CDI cases occurred during the study period.