Healthcare workers, epidemic biological risks - recommendations based on the experience with COVID-19 and Ebolavirus.

Infectious disease outbreaks frequently cause illness and death among Healthcare Workers (HCWs). We compare strategies from recent, past and ongoing outbreak measures used to protect HCWs, including those facing additional challenges such as racial disparities, violence and stigmatization. Outbreaks and pandemics superimposed on countries with preexisting crises have also affected emergency response to these viral outbreaks. Strategies to protect HCWs include adherence to recommended infection prevention and control measures; new technology such as rapid point-of-care tests and remote monitoring; adopting national public health preparedness plans to ensure the supply and allocation of PPE, staff, and testing supplies; occupational health and mental health support services. Lessons learned from recent pandemics should be used by Infection Prevention and Control and Occupational Health staff to refine preparedness plans to protect HCWs better.

DANGER! Crisis Health Workers at Risk.

The occupational hazards of health workers (HWs) in standard work environments have been well defined in both the developed and developing world during routine working conditions. Less defined are the hazards to HWs during pandemics, epidemics, natural disasters, wars, conflicts, and other crises. How do crises affect the infrastructure of medical systems? What are the distinct needs of the patient population during crises? What are the peculiarities of the Crisis Health Worker (CHW)? What are the known CHWs' occupational risks? What are the protective factors? By means of a PubMed search, we synthesized the most relevant publications to try to answer these questions. Failures of healthcare infrastructure and institutions include CHW shortages, insufficient medical supplies, medications, transportation, poorly paid health workers, security concerns, and the absence of firm guidance in health policy. Healthcare needs affecting the patient population and CHWs include crisis-induced injury and illness, hazardous exposures, communicable diseases, mental healthcare, and continuity of care for pre-crisis medical conditions. CHWs' occupational hazards include supply deficiencies, infectious disease transmission, long working hours, staff shortages, financial reimbursements, mental fatigue, physical exhaustion, and inconsistent access to clean water, electricity, and Internet. CHWs suffer from injuries and illnesses that range from immediate, debilitating injuries to chronic, unforeseen effects like mental fatigue, physical exhaustion, anxiety, burnout, and even post-traumatic stress syndrome (PTSD). Protective factors include personal traits such as adaptability and resilience as well as skills learned through structured education and training. Success will be achieved by constructively collaborating with local authorities, local health workers, national military, foreign military, and aid organizations.

Infection Rates and Risk Factors for Infection Among Health Workers During Ebola and Marburg Virus Outbreaks: A Systematic Review.

Background: Infection in health workers (HWs) has characterized outbreaks of Ebola virus disease (EVD) and Marburg virus disease (MVD). We conducted a systematic review to investigate infection and mortality rates and common exposure risks in HWs in EVD and MVD outbreaks. Methods: We searched the EMBASE and PubMed databases to identify articles posted before 27 December 2017, with no language restrictions. Data on the number, frequency, and mortality of HW infection and exposure risks were extracted. Results: Ninety-four articles related to 22 outbreaks were included. HW infections composed 2%-100% of cases in EVD and 5%-50% of cases in MVD outbreaks. Among exposed HWs, 0.6%-92% developed EVD, and 1%-10% developed MVD. HW infection rates were consistent through outbreaks. The most common exposure risk situations were inadequate personal protective equipment and exposure to patients with unrecognized EVD/MVD. Similar risks were reported in past EVD/MVD outbreaks and in the recent outbreak in West Africa. Conclusions: Many outbreaks reported high proportions of infected HWs. Similar HW infection rates and exposure risk factors in both past and recent EVD and MVD outbreaks emphasize the need to improve the implementation of appropriate infection control measures consistently across all healthcare settings.

Heterologous immunity triggered by a single, latent virus in Mus musculus: combined costimulation- and adhesion- blockade decrease rejection.

The mechanisms underlying latent-virus-mediated heterologous immunity, and subsequent transplant rejection, especially in the setting of T cell costimulation blockade, remain undetermined. To address this, we have utilized MHV68 to develop a rodent model of latent virus-induced heterologous alloimmunity. MHV68 infection was correlated with multimodal immune deviation, which included increased secretion of CXCL9 and CXCL10, and with the expansion of a CD8(dim) T cell population. CD8(dim) T cells exhibited decreased expression of multiple costimulation molecules and increased expression of two adhesion molecules, LFA-1 and VLA-4. In the setting of MHV68 latency, recipients demonstrated accelerated costimulation blockade-resistant rejection of skin allografts compared to non-infected animals (MST 13.5 d in infected animals vs 22 d in non-infected animals, p<.0001). In contrast, the duration of graft acceptance was equivalent between non-infected and infected animals when treated with combined anti-LFA-1/anti-VLA-4 adhesion blockade (MST 24 d for non-infected and 27 d for infected, p = n.s.). The combination of CTLA-4-Ig/anti-CD154-based costimulation blockade+anti-LFA-1/anti-VLA-4-based adhesion blockade led to prolonged graft acceptance in both non-infected and infected cohorts (MST>100 d for both, p<.0001 versus costimulation blockade for either). While in the non-infected cohort, either CTLA-4-Ig or anti-CD154 alone could effectively pair with adhesion blockade to prolong allograft acceptance, in infected animals, the prolonged acceptance of skin grafts could only be recapitulated when anti-LFA-1 and anti-VLA-4 antibodies were combined with anti-CD154 (without CTLA-4-Ig, MST>100 d). Graft acceptance was significantly impaired when CTLA-4-Ig alone (no anti-CD154) was combined with adhesion blockade (MST 41 d). These results suggest that in the setting of MHV68 infection, synergy occurs predominantly between adhesion pathways and CD154-based costimulation, and that combined targeting of both pathways may be required to overcome the increased risk of rejection that occurs in the setting of latent-virus-mediated immune deviation.

Use of case reports and the Adverse Event Reporting System in systematic reviews: overcoming barriers to assess the link between Crohn's disease medications and hepatosplenic T-cell lymphoma.

BACKGROUND: To identify demographic and clinical characteristics associated with cases of hepatosplenic T-cell lymphoma (HSTCL) in patients with Crohn's disease, and to assess strength of evidence for a causal relationship between medications and HSTCL in Crohn's disease. METHODS: We identified cases of HSTCL in Crohn's disease in studies included in a comparative effectiveness review of Crohn's disease medications, through a separate search of PubMed and Embase for published case reports, and from the Food and Drug Administration (FDA) Adverse Event Reporting System (AERS). We used three causality assessment tools to evaluate the relationship between medication exposure and HSTCL. RESULTS: We found 37 unique cases of HSTCL in patients with Crohn's disease. Six cases were unique to the published literature and nine were unique to AERS. Cases were typically young (<40 years of age) and male (86%). The most commonly reported medications were anti-metabolites (97%) and anti-tumor necrosis factor alpha (anti-TNFa) medications (76%). Dose and duration of therapy were not consistently reported. Use of aminosalicylates and corticosteroids were rarely reported, despite the high prevalence of these medications in routine treatment. Using the causality assessment tools, it could only be determined that anti-metabolite and anti-TNFa therapies were possible causes of HSTCL in Crohn's disease based on the data contained in the case reports. CONCLUSION: Systematic reviews that incorporate case reports of rare lethal events should search both published literature and AERS, but consideration should be given to the limitations of case reports. In this study, establishing a causative effect other than 'possible' between anti-metabolite or anti-TNFa therapies and HSTCL was not feasible because case reports lacked data required by the causality assessments, and because of the limited applicability of causality assessment tools for rare irreversible events. We recommend minimum reporting requirements for case reports to improve causality assessment and routine reporting of rare life-threatening events, including their absence, in clinical trials to help clinicians determine whether rare adverse events are causally related to a medication.

Expansion of effector memory TCR Vbeta4+ CD8+ T cells is associated with latent infection-mediated resistance to transplantation tolerance.

Therapies that control largely T cell-dependent allograft rejection in humans also possess the undesirable effect of impairing T cell function, leaving transplant recipients susceptible to opportunistic viruses. Prime among these opportunists are the ubiquitous herpesviruses. To date, studies are lacking that address the effect of viruses that establish a true latent state on allograft tolerance or the effect of tolerance protocols on the immune control of latent viruses. By using a mixed chimerism-based tolerance-induction protocol, we found that mice undergoing latent infection with gammaHV68, a murine gamma-herpesvirus closely related to human gamma-herpesviruses such as EBV and Kaposi's sarcoma-associated herpesvirus, significantly resist tolerance to allografts. Limiting the degree of virus reactivation or innate immune response did not reconstitute chimerism in latently infected mice. However, gammaHV68-infected mice showed increased frequency of CD8+ T cell alloreactivity and, interestingly, expansion of virus-induced, alloreactive, "effector/effector memory" TCR Vbeta4+CD8+ T cells driven by the gammaHV68-M1 gene was associated with resistance to tolerance induction in studies using gammaHV68-M1 mutant virus. These results define the viral gene and immune cell types involved in latent infection-mediated resistance to allograft tolerance and underscore the influence of latent herpesviruses on allograft survival.