Evaluation of the Centers for Disease Control and Prevention Recommendations for Hepatitis C Virus Testing in an Urban Emergency Department

BACKGROUND

The Centers for Disease Control and Prevention (CDC) recommends 1-time hepatitis C virus (HCV) testing in the 1945-1965 birth cohort, in addition to targeted risk-based testing. Emergency departments (EDs) are key venues for HCV testing because of the population served and success in HIV screening. We determined the burden of undocumented HCV infection in our ED, providing guidance for implementation of ED-based HCV testing.

METHODS

An 8-week seroprevalence study was conducted in an urban ED in 2013. All patients with excess blood collected for clinical purposes were included. Demographic and clinical information including documented HCV infection was obtained from electronic medical records. HCV antibody testing was performed on excess samples.

RESULTS

Of 4713 patients, 652 (13.8%) were HCV antibody positive. Of these, 204 (31.3%) had undocumented HCV infection. Among patients with undocumented infections, 99 (48.5%) would have been diagnosed based on birth cohort testing, and an additional 54 (26.5%) would be identified by risk-based testing. If our ED adhered to the CDC guidelines, 51 (25.0%) patients with undocumented HCV would not have been tested. Given an estimated 7727 unique ED patients with HCV infection in a 1-year period, birth cohort plus risk-based testing would identify 1815 undocumented infections, and universal testing would identify additional 526 HCV-infected persons.

CONCLUSIONS

Birth cohort-based testing would augment identification of undocumented HCV infections in this ED 2-fold, relative to risk-based testing only. However, our data demonstrate that one-quarter of infections would remain undiagnosed if current CDC birth cohort recommendations were employed, suggesting that in high-risk urban ED settings a practice of universal 1-time testing might be more effective.

Evaluation of hidden HIV infections in an urban ED with a rapid HIV screening program

BACKGROUND

To investigate the prevalence of undiagnosed HIV infections in an emergency department (ED) with an established screening program.

METHODS

Evaluation of the prevalence and risk factors for HIV from an 8-week (June 24, 2007-August 18, 2007) identity-unlinked HIV serosurvey, conducted at the same time as an ongoing opt-in rapid oral-fluid HIV screening program. Testing facilitators offering 24/7 bedside rapid testing to patients aged 18 to 64 years, with concordant collection of excess sera collected as part of routine clinical procedures. Known HIV positivity was determined by (1) medical record review or self-report from the screening program and/or (2) presence of antiretrovirals in serum specimens.

RESULTS

Among 3207 patients, 1165 (36.3%) patients were offered an HIV test. Among those offered, 567 (48.7%) consented to testing. Concordance identity-unlinked study revealed that the prevalence of undiagnosed infections was as follows: 2.3% in all patients, 1.0% in those offered testing vs 3.0% in those not offered testing (P < .001); and 1.3% in those who declined testing compared with 0.4% in those who were tested (P = .077). Higher median viral loads were observed in those not offered testing (14255 copies/mL; interquartile range, 1147-64354) vs those offered testing (1865 copies/mL; interquartile range, undetectable-21786), but the difference was not statistically significant.

CONCLUSIONS

High undiagnosed HIV prevalence was observed in ED patients who were not offered HIV testing and those who declined testing, compared with those who were tested. This indicates that even with an intensive facilitator-based rapid HIV screening model, significant missed opportunities remain with regard to identifying undiagnosed infections in the ED.

A novel factor produced by placental cells with activity against HIV-1

The factors controlling the dynamics of HIV-1 transmission from mother to infant are not clearly known. Previous studies have suggested the existence of maternal and placental protective mechanisms that inhibit viral replication in utero. Preliminary studies from our laboratory revealed that supernatant from placental stromal cells protected HIV-1-infected PBMC from virus-induced apoptosis and suppressed virus production. We have attempted to characterize the antiviral activity of this placental factor (PF) and delineate the stages of HIV-1 replication affected. This activity was not due to the presence of any known cytokine reported to have anti-HIV effect. Direct exposure to PF had no suppressive effect on the infectivity of cell-free HIV-1, and envelope-mediated membrane fusion appeared to be unaffected. Western blot analysis of HIV-1 from infected PBMC treated with PF revealed that expression of all viral proteins was reduced proportionately, both intracellularly and in released virions. However, exposure of HIV-1-infected cells to PF resulted in production of virions with 10-100-fold-reduced infectivity. PF-treated virions contained two- to threefold reduced ratios of cyclophilin A:Gag protein as compared with untreated virus. Reduced cyclophilin A content resulting in decreased binding of cyclophilin A to Gag could account, in part, for the observed reduction in infectivity. Our results suggest that placental cells produce an antiviral factor that protects the fetus during gestation and may have therapeutic potential.

A Novel Factor Produced by Placental Cells with Activity Against HIV-1

The factors controlling the dynamics of HIV-1 transmission from mother to infant are not clearly known. Previous studies have suggested the existence of maternal and placental protective mechanisms that inhibit viral replication in utero. Preliminary studies from our laboratory revealed that supernatant from placental stromal cells protected HIV-1-infected PBMC from virus-induced apoptosis and suppressed virus production. We have attempted to characterize the antiviral activity of this placental factor (PF) and delineate the stages of HIV-1 replication affected. This activity was not due to the presence of any known cytokine reported to have anti-HIV effect. Direct exposure to PF had no suppressive effect on the infectivity of cell-free HIV-1, and envelope-mediated membrane fusion appeared to be unaffected. Western blot analysis of HIV-1 from infected PBMC treated with PF revealed that expression of all viral proteins was reduced proportionately, both intracellularly and in released virions. However, exposure of HIV-1-infected cells to PF resulted in production of virions with 10–100-fold-reduced infectivity. PF-treated virions contained two- to threefold reduced ratios of cyclophilin A:Gag protein as compared with untreated virus. Reduced cyclophilin A content resulting in decreased binding of cyclophilin A to Gag could account, in part, for the observed reduction in infectivity. Our results suggest that placental cells produce an antiviral factor that protects the fetus during gestation and may have therapeutic potential.

Extensive evaluation of a seronegative participant in an HIV-1 vaccine trial as a result of false-positive PCR

BACKGROUND

In the USA, more than 2000 volunteers have received one or more experimental HIV-1 vaccines in phase I and II clinical trials, and there have been breakthrough HIV-1 infections among participants receiving vaccine and placebo. Serological diagnosis of new HIV-1 infections in vaccine-trial participants will become increasingly complicated as more viral components are used in vaccines. Recognition of this problem has led to a reliance on viral-genome measurement to distinguish vaccine-induced immunity from HIV-1 infection. Currently, quantitative RNA measurement is expensive, prone to contamination, and reliable only in laboratories certified by manufacturers or that have quality-control programmes.

METHODS

A high-risk vaccinee presented after an acute febrile episode and was tested for HIV-1 infection by reverse transcriptase (RT) PCR of viral RNA. Further extensive tests were required to clarify the HIV-1 infection and immune status of the vaccinee, including repeat RT-PCR, nested DNA PCR, western blot, lymphoproliferation assay, cytotoxic T-cell lysis, CD8-depleted co-culture, and HIV-1 challenge culture.

FINDINGS

Initial testing of plasma by RNA RT-PCR was reported as positive. This result was not confirmed by viral cultures, nested DNA PCR, western blot, or EIA. Additional RNA RT-PCR assays gave positive results from earlier occasions in the vaccine trial. Eventually, testing of all previously reactive samples by RNA RT-PCR was repeated in a quality-controlled laboratory, and confirmed the negative HIV-1 status of the individual.

INTERPRETATION

This case report exemplifies the difficulties with use of viral-genome measurement as a screening test to diagnose HIV-1 infection, particularly in individuals who have ever participated in HIV-1 vaccine trials. Monitoring of large numbers of phase III vaccinees by RNA RT-PCR will not be feasible. The design of efficacy trials for new vaccines should be in parallel with development of antibody-based diagnostic tests that are capable of differentiating between immunisation and true HIV-1 infection.