Acute severe hepatitis outbreak in children: A perfect storm. What do we know, and what questions remain?

During the first half of 2022, the World Health Organization reported an outbreak of acute severe hepatitis of unknown aetiology (AS-Hep-UA) in children, following initial alerts from the United Kingdom (UK) where a cluster of cases was first observed in previously well children aged <6 years. Sporadic cases were then reported across Europe and worldwide, although in most countries incidence did not increase above the expected baseline. There were no consistent epidemiological links between cases, and microbiological investigations ruled out known infectious causes of hepatitis. In this review, we explore the evidence for the role of viral infection, superimposed on a specific host genetic background, as a trigger for liver pathology. This hypothesis is based on a high prevalence of Human Adenovirus (HAdV) 41F in affected children, together with metagenomic evidence of adeno-associated virus (Adeno-associated viruses)-2, which is a putative trigger for an immune-mediated liver injury. Roles for superantigen-mediated pathology have also been explored, with a focus on the potential contribution of SARS-CoV-2 infection. Affected children also had a high frequency of the MHC allele HLA-DRB1*04:01, supporting an immunological predisposition, and may have been vulnerable to viral coinfections due to disruption in normal patterns of exposure and immunity as a result of population lockdowns during the COVID-19 pandemic. We discuss areas of ongoing uncertainty, and highlight the need for ongoing scrutiny to inform clinical and public health interventions for this outbreak and for others that may evolve in future.

Viral Diagnosis of Hepatitis B and Delta: What We Know and What Is Still Required? Specific Focus on Low- and Middle-Income Countries.

To achieve the World Health Organization's (WHO) goals of eradicating viral hepatitis globally by 2030, the regional prevalence and epidemiology of hepatitis B virus (HBV) and hepatitis delta virus (HDV) coinfection must be known in order to implement preventiveon and treatment strategies. HBV/HDV coinfection is considered the most severe form of vira l hepatitis due to it's rapid progression towards cirrhosis, hepatocellular carcinoma, and liver-related death. The role of simplified diagnosticsis tools for screening and monitoring HBV/HDV-coinfected patients is crucial. Many sophisticated tools for diagnoses have been developed for detection of HBV alone as well as HBV/HDV coinfection. However, these advanced techniques are not widely available in low-income countries and there is no standardization for HDV detection assays, which are used for monitoring the response to antiviral therapy. More accessible and affordable alternative methods, such as rapid diagnostic tests (RDTs), are being developed and validated for equipment-free and specific detection of HBV and HDV. This review will provide some insight into both existing and diagnosis tools under development, their applicability in developing countries and how they could increase screening, patient monitoring and treatment eligibility.

Venous thromboembolism in COVID-19 compared to non-COVID-19 cohorts: A systematic review with meta-analysis.

BACKGROUND: Many studies confirmed an association between COVID-19 and venous thromboembolism (VTE). Whether the risk of VTE significantly differed between COVID-19 cohorts and non-COVID-19 cohorts with similar disease severity remains unknown. OBJECTIVES: The aim of this systematic review with meta-analysis was to compare the rate of VTE between COVID-19 and non-COVID-19 cohorts with similar disease severity. METHODS: A systematic literature search (MEDLINE, Embase and Google Scholar) was conducted from January 1, 2020 to March 31, 2021 to identify studies reporting VTE in COVID-19. Relative risks (RR) were estimated for the effect measure with 95% confidence intervals. RESULTS: Seven studies (41,768 patients) evaluated VTE in COVID-19 cohorts compared to non-COVID-19 cohorts. The overall risk of VTE (RR 1.18; 95%CI 0.79-1.77; p = 0.42; I2 = 54%), pulmonary embolism (RR 1.25; 95%CI 0.77-2.03; p = 0.36; I2 = 52%) and deep venous thrombosis (RR 0.92; 95%CI 0.52-1.65; p = 0.78; I2 = 0%) did not significantly differ between COVID-19 and non-COVID-19 cohorts. However, subgroup analyses suggested an increased risk of VTE amongst CODID-19 versus non COVID-19 cohorts when only patients hospitalized within the intensive care unit (ICU) were considered (RR 3.10; 95%CI 1.54-6.23), which was not observed in cohorts of predominantly non-ICU patients (RR 0.95; 95%CI 0.81-1.11) (Pinteraction = 0.001). CONCLUSION: There was no signal for a difference in VTE in COVID-19 cohorts compared to non-COVID-19 cohorts, except for the subgroup of patients hospitalized in the ICU. These results should be viewed as exploratory and further studies are needed to confirm these results.

Arterial and venous thromboembolism in COVID-19: a study-level meta-analysis.

BACKGROUND: The prevalence of venous thromboembolic event (VTE) and arterial thromboembolic event (ATE) thromboembolic events in patients with COVID-19 remains largely unknown. METHODS: In this meta-analysis, we systematically searched for observational studies describing the prevalence of VTE and ATE in COVID-19 up to 30 September 2020. RESULTS: We analysed findings from 102 studies (64 503 patients). The frequency of COVID-19-related VTE was 14.7% (95% CI 12.1% to 17.6%, I2=94%; 56 studies; 16 507 patients). The overall prevalence rates of pulmonary embolism (PE) and leg deep vein thrombosis were 7.8% (95% CI 6.2% to 9.4%, I2=94%; 66 studies; 23 117 patients) and 11.2% (95% CI 8.4% to 14.3%, I2=95%; 48 studies; 13 824 patients), respectively. Few were isolated subsegmental PE. The VTE prevalence was significantly higher in intensive care unit (ICU) (23.2%, 95% CI 17.5% to 29.6%, I2=92%, vs 9.0%, 95% CI 6.9% to 11.4%, I2=95%; pinteraction<0.0001) and in series systematically screening patients compared with series testing symptomatic patients (25.2% vs 12.7%, pinteraction=0.04). The frequency rates of overall ATE, acute coronary syndrome, stroke and other ATE were 3.9% (95% CI 2.0% to to 3.0%, I2=96%; 16 studies; 7939 patients), 1.6% (95% CI 1.0% to 2.2%, I2=93%; 27 studies; 40 597 patients) and 0.9% (95% CI 0.5% to 1.5%, I2=84%; 17 studies; 20 139 patients), respectively. Metaregression and subgroup analyses failed to explain heterogeneity of overall ATE. High heterogeneity limited the value of estimates. CONCLUSIONS: Patients admitted in the ICU for severe COVID-19 had a high risk of VTE. Conversely, further studies are needed to determine the specific effects of COVID-19 on the risk of ATE or VTE in less severe forms of the disease.

Atherosclerotic Cardiovascular Events in Patients Infected With Human Immunodeficiency Virus and Hepatitis C Virus.

BACKGROUND: An increased risk of cardiovascular disease (CVD) was reported in patients coinfected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV), without identifying factors associated with atherosclerotic CVD (ASCVD) events. METHODS: HIV-HCV coinfected patients were enrolled in the Agence Nationale de Recherches sur le Sida et les hépatites virales (ANRS) CO13 HEPAVIH nationwide cohort. Primary outcome was total ASCVD events. Secondary outcomes were coronary and/or cerebral ASCVD events, and peripheral artery disease (PAD) ASCVD events. Incidences were estimated using the Aalen-Johansen method. Factors associated with ASCVD were identified using cause-specific Cox proportional hazards models. RESULTS: At baseline, median age of the study population (N = 1213) was 45.4 (interquartile range [IQR] 42.1-49.0) years and 70.3% were men. After a median follow-up of 5.1 (IQR 3.9-7.0) years, the incidence was 6.98 (95% confidence interval [CI], 5.19-9.38) per 1000 person-years for total ASCVD events, 4.01 (2.78-6.00) for coronary and/or cerebral events, and 3.17 (2.05-4.92) for PAD ASCVD events. Aging (hazard ratio [HR] 1.06; 95% CI, 1.01-1.12), prior CVD (HR 8.48; 95% CI, 3.14-22.91), high total cholesterol (HR 1.43; 95% CI, 1.11-1.83), high-density lipoprotein cholesterol (HR 0.22; 95% CI, 0.08-0.63), statin use (HR 3.31; 95% CI, 1.31-8.38), and high alcohol intake (HR 3.18; 95% CI, 1.35-7.52) were independently associated with total ASCVD events, whereas undetectable baseline viral load (HR 0.41, 95% CI, 0.18-0.96) was associated with coronary and/or cerebral events. CONCLUSIONS: HIV-HCV coinfected patients experienced a high incidence of ASCVD events. Some traditional cardiovascular risk factors were the main determinants of ASCVD. Controlling cholesterol abnormalities and maintaining undetectable HIV RNA are essential to control cardiovascular risk.

No evident association of nasal carriage of Staphylococcus aureus or its small-colony variants with cotrimoxazole use or ANCA-associated vasculitis relapses.

OBJECTIVE: To identify the role of Staphylococcus aureus (SA) or its intracellular small-colony variant phenotype (SCV) with co-trimoxazole (CTX) or ANCA-associated vasculitis (AAV) activity. METHODS: All consecutive AAV patients with granulomatosis with polyangiitis (GPA), eosinophilic GPA or microscopic polyangiitis, followed at the French National Vasculitis Referral Center (09/2012-05/2013), and hospitalized non-AAV controls, exclusively for SA/SCV carriage comparisons, were enrolled. All had bilateral anterior nasal swab cultures. Nasal SA or SCV carriage was determined and associations with relapse(s), BVAS, ANCA-positivity, anti-staphylococcal and immunosuppressant use, were analysed ⩾4 years post-inclusion. RESULTS: Nasal SA carriage rates did not differ among AAVs (P = 0.53): GPA (24/80; 30%), EGPA (7/28; 25%) and microscopic polyangiitis (3/11; 27.3%); and the rate was less frequent in controls than in GPA patients not taking CTX (P = 0.04). AAV patients taking CTX prophylaxis had less nasal SA carriage (8.7% vs 36.2%; P = 0.02). Nasal SA carriage or CTX use did not modify relapse rates, BVAS or ANCA-positivity at inclusion or during follow-up. Nasal SCV carriage, found in 15/207 (7.2%) patients, was similar for GPA (10/24; 41.7%), microscopic polyangiitis (2/7; 28.6%) and eosinophilic GPA (2/3; 66.7%), but higher (P = 0.02) than controls (1/14; 7.1%). SCV carriage by AAV groups did not modify relapse rates or ANCA positivity at inclusion or during follow-up; a trend towards higher BVAS was observed only for anti-PR3 ANCA patients. CONCLUSION: Nasal SA or SCV carriage was comparable among AAVs but more frequent than in controls. Nasal SA or SCV carriage and CTX use did not modify AAV relapse rates.