Innate-like Cytotoxic Function of Bystander-Activated CD8+ T Cells Is Associated with Liver Injury in Acute Hepatitis A.

Acute hepatitis A (AHA) involves severe CD8+ T cell-mediated liver injury. Here we showed during AHA, CD8+ T cells specific to unrelated viruses became activated. Hepatitis A virus (HAV)-infected cells produced IL-15 that induced T cell receptor (TCR)-independent activation of memory CD8+ T cells. TCR-independent activation of non-HAV-specific CD8+ T cells were detected in patients, as indicated by NKG2D upregulation, a marker of TCR-independent T cell activation by IL-15. CD8+ T cells derived from AHA patients exerted innate-like cytotoxicity triggered by activating receptors NKG2D and NKp30 without TCR engagement. We demonstrated that the severity of liver injury in AHA patients correlated with the activation of HAV-unrelated virus-specific CD8+ T cells and the innate-like cytolytic activity of CD8+ T cells, but not the activation of HAV-specific T cells. Thus, host injury in AHA is associated with innate-like cytotoxicity of bystander-activated CD8+ T cells, a result with implications for acute viral diseases.

Biochemical analysis of the host factor activity of ZCCHC14 in hepatitis A virus replication.

Relatively little is known of the mechanisms underlying hepatitis A virus (HAV) genome replication. Unlike other well-studied picornaviruses, HAV RNA replication requires the zinc finger protein ZCCHC14 and non-canonical TENT4 poly(A) polymerases with which it forms a complex. The ZCCHC14-TENT4 complex binds to a stem-loop located within the internal ribosome entry site (IRES) in the 5' untranslated RNA (5'UTR) and is essential for viral RNA synthesis, but the underlying mechanism is unknown. Here, we describe how different ZCCHC14 domains contribute to its RNA-binding, TENT4-binding, and HAV host factor activities. We show that the RNA-binding activity of ZCCHC14 requires both a sterile alpha motif (SAM) and a downstream unstructured domain (D4) and that ZCCHC14 contains two TENT4-binding sites: one at the N-terminus and the other around D4. Both RNA-binding and TENT4-binding are required for HAV host factor activity of ZCCHC14. We also demonstrate that the location of the ZCCHC14-binding site within the 5'UTR is critical for its function. Our study provides a novel insight into the function of ZCCHC14 and helps elucidate the mechanism of the ZCCHC14-TENT4 complex in HAV replication.IMPORTANCEThe zinc finger protein ZCCHC14 is an essential host factor for both hepatitis A virus (HAV) and hepatitis B virus (HBV). It recruits the non-canonical TENT4 poly(A) polymerases to viral RNAs and most likely also a subset of cellular mRNAs. Little is known about the details of these interactions. We show here the functional domains of ZCCHC14 that are involved in binding to HAV RNA and interactions with TENT4 and describe previously unrecognized peptide sequences that are critical for the HAV host factor activity of ZCCHC14. Our study advances the understanding of the ZCCHC14-TENT4 complex and how it functions in regulating viral and cellular RNAs.

NS5A domain I antagonises PKR to facilitate the assembly of infectious hepatitis C virus particles.

Hepatitis C virus NS5A is a multifunctional phosphoprotein comprised of three domains (DI, DII and DIII). DI and DII have been shown to function in genome replication, whereas DIII has a role in virus assembly. We previously demonstrated that DI in genotype 2a (JFH1) also plays a role in virus assembly, exemplified by the P145A mutant which blocked infectious virus production. Here we extend this analysis to identify two other conserved and surface exposed residues proximal to P145 (C142 and E191) that exhibited no defect in genome replication but impaired virus production. Further analysis revealed changes in the abundance of dsRNA, the size and distribution of lipid droplets (LD) and the co-localisation between NS5A and LDs in cells infected with these mutants, compared to wildtype. In parallel, to investigate the mechanism(s) underpinning this role of DI, we assessed the involvement of the interferon-induced double-stranded RNA-dependent protein kinase (PKR). In PKR-silenced cells, C142A and E191A exhibited levels of infectious virus production, LD size and co-localisation between NS5A and LD that were indistinguishable from wildtype. Co-immunoprecipitation and in vitro pulldown experiments confirmed that wildtype NS5A domain I (but not C142A or E191A) interacted with PKR. We further showed that the assembly phenotype of C142A and E191A was restored by ablation of interferon regulatory factor-1 (IRF1), a downstream effector of PKR. These data suggest a novel interaction between NS5A DI and PKR that functions to evade an antiviral pathway that blocks virus assembly through IRF1.

Infectious hepatitis E virus excreted into the vagina.

Hepatitis E virus (HEV) persists in the male genital tract that associates with infertility. However, the presence of HEV in the female genital tract is unreported. Vaginal secretions, cervical smears, and cervix uteri were collected to explore the presence of HEV in the female genital tract. HEV RNA and/or antigens were detected in the vaginal secretions, cervical smears, and the cervix uteri of women. The infectivity of HEV excreted into vaginal secretions was further validated in vitro. In addition, HEV replicates in the female genital tract were identified in HEV-infected animal models by vaginal injection or vaginal mucosal infection to imitate sexual transmission. Serious genital tract damage and inflammatory responses with significantly elevated mucosal innate immunity were observed in women or animals with HEV vaginal infection. Results demonstrated HEV replicates in the female genital tract and causes serious histopathological damage and inflammatory responses.

Central Nervous System Stromal Cells Control Local CD8(+) T Cell Responses during Virus-Induced Neuroinflammation.

Stromal cells generate a complex cellular scaffold that provides specialized microenvironments for lymphocyte activation in secondary lymphoid organs. Here, we assessed whether local activation of stromal cells in the central nervous system (CNS) is mandatory to transfer immune recognition from secondary lymphoid organs into the infected tissue. We report that neurotropic virus infection in mice triggered the establishment of such stromal cell niches in the CNS. CNS stromal cell activation was dominated by a rapid and vigorous production of CC-motif chemokine receptor (CCR) 7 ligands CCL19 and CCL21 by vascular endothelial cells and adjacent fibroblastic reticular cell (FRC)-like cells in the perivascular space. Moreover, CCR7 ligands produced by CNS stromal cells were crucial to support recruitment and local re-activation of antiviral CD8(+) T cells and to protect the host from lethal neuroinflammatory disease, indicating that CNS stromal cells generate confined microenvironments that control protective T cell immunity.

The ZCCHC14/TENT4 complex is required for hepatitis A virus RNA synthesis.

Despite excellent vaccines, resurgent outbreaks of hepatitis A have caused thousands of hospitalizations and hundreds of deaths within the United States in recent years. There is no effective antiviral therapy for hepatitis A, and many aspects of the hepatitis A virus (HAV) replication cycle remain to be elucidated. Replication requires the zinc finger protein ZCCHC14 and noncanonical TENT4 poly(A) polymerases with which it associates, but the underlying mechanism is unknown. Here, we show that ZCCHC14 and TENT4A/B are required for viral RNA synthesis following translation of the viral genome in infected cells. Cross-linking immunoprecipitation sequencing (CLIP-seq) experiments revealed that ZCCHC14 binds a small stem-loop in the HAV 5' untranslated RNA possessing a Smaug recognition-like pentaloop to which it recruits TENT4. TENT4 polymerases lengthen and stabilize the 3' poly(A) tails of some cellular and viral mRNAs, but the chemical inhibition of TENT4A/B with the dihydroquinolizinone RG7834 had no impact on the length of the HAV 3' poly(A) tail, stability of HAV RNA, or cap-independent translation of the viral genome. By contrast, RG7834 inhibited the incorporation of 5-ethynyl uridine into nascent HAV RNA, indicating that TENT4A/B function in viral RNA synthesis. Consistent with potent in vitro antiviral activity against HAV (IC50 6.11 nM), orally administered RG7834 completely blocked HAV infection in Ifnar1-/- mice, and sharply reduced serum alanine aminotransferase activities, hepatocyte apoptosis, and intrahepatic inflammatory cell infiltrates in mice with acute hepatitis A. These results reveal requirements for ZCCHC14-TENT4A/B in hepatovirus RNA synthesis, and suggest that TENT4A/B inhibitors may be useful for preventing or treating hepatitis A in humans.

Deaths Associated with Pediatric Hepatitis of Unknown Etiology, United States, October 2021-June 2023.

During October 2021-June 2023, a total of 392 cases of acute hepatitis of unknown etiology in children in the United States were reported to Centers for Disease Control and Prevention as part of national surveillance. We describe demographic and clinical characteristics, including potential involvement of adenovirus in development of acute hepatitis, of 8 fatally ill children who met reporting criteria. The children had diverse courses of illness. Two children were immunocompromised when initially brought for care. Four children tested positive for adenovirus in multiple specimen types, including 2 for whom typing was completed. One adenovirus-positive child had no known underlying conditions, supporting a potential relationship between adenovirus and acute hepatitis in previously healthy children. Our findings emphasize the importance of continued investigation to determine the mechanism of liver injury and appropriate treatment. Testing for adenovirus in similar cases could elucidate the role of the virus.

Concurrent Outbreaks of Hepatitis A, Invasive Meningococcal Disease, and Mpox, Florida, USA, 2021-2022.

In 2022, concurrent outbreaks of hepatitis A, invasive meningococcal disease (IMD), and mpox were identified in Florida, USA, primarily among men who have sex with men. The hepatitis A outbreak (153 cases) was associated with hepatitis A virus genotype IA. The IMD outbreak (44 cases) was associated with Neisseria meningitidis serogroup C, sequence type 11, clonal complex 11. The mpox outbreak in Florida (2,845 cases) was part of a global epidemic. The hepatitis A and IMD outbreaks were concentrated in Central Florida and peaked during March--June, whereas mpox cases were more heavily concentrated in South Florida and had peak incidence in August. HIV infection was more common (52%) among mpox cases than among hepatitis A (21%) or IMD (34%) cases. Where feasible, vaccination against hepatitis A, meningococcal disease, and mpox should be encouraged among at-risk groups and offered along with program services that target those groups.

Assessing vaccine-induced immunity against pneumococcus, hepatitis A and B over a 9-year follow-up in pediatric liver transplant recipients: A nationwide retrospective study.

Pediatric liver transplant recipients are particularly at risk of infections. The most cost-effective way to prevent infectious complications is through vaccination, which can potentially prevent infections due to hepatitis B (HBV) virus, hepatitis A virus (HAV), and invasive pneumococcal diseases. Here, we performed a retrospective analysis of HBV, HAV, and pneumococcal immunity in pediatric liver transplant recipients between January 1, 2009, and December 31, 2020, to collect data on immunization and vaccine serology. A total of 94% (58/62) patients had available vaccination records. At transplant, 90% (45/50) were seroprotected against HBV, 63% (19/30) against HAV, and 78% (18/23) had pneumococcal immunity, but immunity against these 3 pathogens remained suboptimal during the 9-year follow-up. A booster vaccine was administered to only 20% to 40% of patients. Children who had received >4 doses of HBV vaccine and > 2 doses of HAV vaccine pretransplant displayed a higher overall seroprotection over time post-solid organ transplant. Our findings suggest that a serology-based approach should be accompanied by a more systematic follow-up of vaccination, with special attention paid to patients with an incomplete vaccination status at time of transplant.

A case of hepatitis-associated aplastic anaemia following living-donor liver transplantation for fulminant hepatitis showing loss of heterozygosity in the 6p chromosome in the affected liver.

The mechanisms underlying hepatitis-associated aplastic anaemia (HAAA) that occurs several weeks after the development of acute hepatitis are unknown. A 20-year-old male developed HAAA following living-donor liver transplantation for fulminant hepatitis. The patient's leucocytes lacked HLA-class I due to loss of heterozygosity in the short arm of chromosome 6p (6pLOH). Interestingly, the patient's liver cells resected during the transplantation also exhibited 6pLOH that affected the same HLA haplotype as the leucocytes, suggesting that CD8+ T cells recognizing antigens presented by specific HLA molecules on liver cells may have attacked the haematopoietic stem cells of the patient, leading to the HAAA development.

Drug Screening for Hepatitis A Virus (HAV): Nicotinamide Inhibits c-Jun Expression and HAV Replication.

Hepatitis A virus (HAV) infection often causes acute hepatitis, which results in a case fatality rate of 0.2% and fulminant hepatitis in 0.5% of cases. However, no specific potent anti-HAV drug is available on the market to date. In the present study, we focused on inhibition of HAV internal ribosomal entry site (IRES)-mediated translation and investigated novel therapeutic drugs through drug repurposing by screening for inhibitors of HAV IRES-mediated translation and cell viability using a reporter assay and cell viability assay, respectively. The initial screening of 1,158 drugs resulted in 77 candidate drugs. Among them, nicotinamide significantly inhibited HAV HA11-1299 genotype IIIA replication in Huh7 cells. This promising drug also inhibited HAV HM175 genotype IB subgenomic replicon and HAV HA11-1299 genotype IIIA replication in a dose-dependent manner. In the present study, we found that nicotinamide inhibited the activation of activator protein 1 (AP-1) and that knockdown of c-Jun, which is one of the components of AP-1, inhibited HAV HM175 genotype IB IRES-mediated translation and HAV HA11-1299 genotype IIIA and HAV HM175 genotype IB replication. Taken together, the results showed that nicotinamide inhibited c-Jun, resulting in the suppression of HAV IRES-mediated translation and HAV replication, and therefore, it could be useful for the treatment of HAV infection. IMPORTANCE Drug screening methods targeting HAV IRES-mediated translation with reporter assays are attractive and useful for drug repurposing. Nicotinamide (vitamin B3, niacin) has been shown to effectively inhibit HAV replication. Transcription complex activator protein 1 (AP-1) plays an important role in the transcriptional regulation of cellular immunity or viral replication. The results of this study provide evidence that AP-1 is involved in HAV replication and plays a role in the HAV life cycle. In addition, nicotinamide was shown to suppress HAV replication partly by inhibiting AP-1 activity and HAV IRES-mediated translation. Nicotinamide may be useful for the control of acute HAV infection by inhibiting cellular AP-1 activity during HAV infection processes.

HIV pre-exposure prophylaxis services, provision, and delivery in the European treatment network of HIV, hepatitis and global emerging infectious diseases (NEAT ID).

OBJECTIVES: We conducted a survey to evaluate HIV pre-exposure prophylaxis (PrEP) practices in a European clinical research network on HIV, hepatitis, and global infectious diseases (NEAT ID). METHODS: An online survey comprising 22 questions was sent via a secure electronic tool to the investigating physician of each of the 342 NEAT ID study centres across 15 European countries in November 2020. RESULTS: In total, 50 sites from 12 countries responded (15% response rate). Most sites were in Western Europe, two were in Poland, and one was in Hungary. Of the responding sites, 45 provided PrEP services for a total of 27 416 PrEP users, with 1361 new PrEP initiators each month. These centres supplied PrEP for men who have sex with men (100%), people who inject drugs (84%), sex workers (84%), women (62%), and transgender women (31%). PrEP persistence after 1 year was >90%, 75%-90%, and 40%-75% in 17, 24, and 4 centres, respectively. In total, 32/45 (71%) centres reported strong community-based organization commitment at their site, and 15/45 (33%) centres developed task-shifting processes to deliver PrEP through nurses (11/15), pharmacists (5/15), and key-population peers (2/15). The biggest barriers to implementation of PrEP were low awareness of and knowledge about PrEP (47%), unwillingness to disclose sexual identity or at-risk behaviour (36%), and lack of administrative support (29%). Of the 45 centres, 32 (71%) have already been involved in PrEP research and 43 (96%) were interested in participating in such studies. CONCLUSIONS: The few NEAT ID centres that responded to the survey showed disparities in PrEP deployment and practices despite a common interest in participating in research in this field.

Hepatitis A hospitalisations in the United States and risk factors for inpatient mortality: A nationwide population study, 1998-2020.

Hepatitis A virus infections in the United States have been declining; however, recent widespread outbreaks have brought the disease back into the spotlight. We aim to describe the epidemiology of hepatitis A hospitalisations from 1998 to 2020 in the United States and investigate risk factors for inpatient mortality. We utilised the National Inpatient Sample database and identified hepatitis A-related hospitalisations using ICD-9 and ICD-10 diagnosis codes. Demographic and clinical data including death, coinfections, comorbidities and pregnancy status were extracted. Data were analysed by logistic and Poisson regression. We identified a total of 213,681 hepatitis A-related hospitalisations between 1998 and 2020, with hospitalisation rates ranging between 22.4 per 1,000,000 and 62.9 per 1,000,000. Between 1998 and 2015, the hospitalisation rate for hepatitis A was decreasing (IRR = 0.98; 95% CI: 0.97-0.98; p < .001); however, between 2015 and 2020, it increased overall (IRR = 1.22; 95% CI: 1.21-1.23; p < .001). The overall inpatient mortality rate was 2.7%. Age ≥55 years (OR = 1.84; 95% CI: 1.41-2.40; p < .001), alcoholic cirrhosis (OR = 2.53; 95% CI: 1.64-3.90; p < .001), ascites (OR = 2.65; 95% CI: 1.86-3.78; p < .001), hepatorenal syndrome (OR = 9.04; 95% CI: 5.93-13.80; p < .001), heart failure (OR = 1.76; 95% CI: 1.29-2.39; p < .001), pulmonary hypertension (OR = 2.02; 95% CI: 1.28-3.19; p = .003) and malignant neoplasm (OR = 1.75; 95% CI: 1.25-2.45; p = .001) were associated with increased odds of mortality. Tobacco use disorder (OR = 0.52; 95% CI: 0.38-0.70; p < .001) was associated with decreased odds of mortality. None of the hepatitis A-associated hospitalisations involving pregnant women resulted in death. Hepatitis A hospitalisations initially declined but increased rapidly after 2015. Certain risk factors can be used to predict prognosis of hospitalised patients.

International disease burden of acute viral hepatitis among adolescents and young adults: An observational study.

Adolescents and young adults are the driving force of social development, and the prevalence of acute viral hepatitis (AVH) in this population cannot be ignored. At present, there are few studies on the disease burden of AVH in this age group, and most studies focus on chronic liver disease. In this study, we identified global trends in the burden of AVH among adolescents and young adults (15-29) to help policymakers implement precise disease interventions. In this observational study of disease trends, we collected data exclusively from the Global Burden of Disease (GBD) 2019 study. This study examined the trends in the prevalence, incidence and mortality of AVH among adolescents and young adults in 21 regions of the world from 2009 to 2019. Age-specific disease trends were analysed with a joinpoint regression model. The overall global disease burden of AVH declined. The prevalence rate per 100,000 people decreased from 316.13 in 2009 to 198.79 in 2019, the incidence rate decreased from 3245.52 in 2009 to 2091.93 in 2019, and the death rate decreased from 0.87 in 2009 to 0.43 in 2019. During the study period, the prevalence of hepatitis B virtues (HBV) in the young population decreased, but the downward trend of other types of hepatitis other than HBV was not obvious, especially HAV, which even showed an upward trend. Among adolescents and young adults aged 15-29 years, Western Saharan Africa had the highest prevalence of AVH in 2019. There were significant differences in mortality rates among different age groups; 20-24 was the age group with the highest mortality rate from 2009 to 2019, followed by the 15-19 and 25-29 age groups. Although the overall global AVH disease burden declined, some causes of AVH, such as HAV, showed an upward trend during the study period. In addition, the prevalence of AVH among adolescents and young adults in Asia and Africa was higher than that in other parts of the world and warrants more attention. Finally, more research should be conducted on mortality in the 20-24 age group.

Hepatitis after gene therapy, what are the possible causes?

Hepatitis is a common adverse event following gene therapy for haemophilia, often associated with a loss of transgene expression. Investigating the potential causes and implications of this is crucial for the overall success of treatment. Gene therapy trials using adeno-associated virus (AAV) vectors have demonstrated promising results marked by increases in factor FVIII and FIX levels and reductions in episodes of bleeding. However, hepatocellular injury characterised by elevations in alanine aminotransferases (ALT) has been noted. This liver injury is typically transient and asymptomatic, posing challenges in determining its clinical significance. Proposed causes encompass immune-mediated responses, notably T cell cytotoxicity in response to the AAV vector, direct liver injury from the viral capsid or transcribed protein via the unfolded protein response and pre-existing liver conditions. Liver biopsy data conducted years post-gene therapy infusion has shown sinusoidal infiltration without significant inflammation. The overall safety profile of gene therapy remains favourable with no evidence drug-induced liver injury (DILI) based on Hy's Law criteria. Essential pre-therapy monitoring and identifying patients at high risk of liver injury should involve liver function tests and non-invasive fibroscans, while novel blood-based biomarkers are under exploration. Further research is required to comprehend the mechanisms underlying transaminitis, loss of transgene expression and long-term effects on the liver, providing insights for optimising gene therapy for haemophilia.

Examining the interim proposal for name change to steatotic liver disease in the US population.

BACKGROUND AND AIMS: Fatty liver is the commonest liver condition globally and traditionally associated with NAFLD. A consensus meeting was held in Chicago to explore various terminologies. Herein, we explore the proposed changes in nomenclature in a population data set from the US. APPROACH AND RESULTS: Statistical analysis was conducted using survey-weighted analysis. Assessment of fatty liver was conducted with vibration-controlled transient elastography. A controlled attenuation parameter of 288 dB/m was used to identify hepatic steatosis. Patients were classified into nonalcoholic steatotic liver disease, alcohol-associated steatotic liver disease, and viral hepatitis steatotic liver disease. Liver stiffness measures at ≥8.8, ≥11.7, and ≥14 kPa were used to identify clinically significant fibrosis, advanced fibrosis, and cirrhosis, respectively. A total of 5102 individuals were included in the analysis. Using a survey-weighted analysis, a total of 25.43%, 6.95%, and 0.73% of the population were classified as nonalcoholic steatotic liver disease, alcohol-associated steatotic liver disease, and viral hepatitis steatotic liver disease, respectively. A sensitivity analysis at controlled attenuation parameter of 248 dB/m and fatty liver index found similar distribution. In a comparison between nonalcoholic steatotic liver disease, alcohol-associated steatotic liver disease, and viral hepatitis steatotic liver disease, there was no significant difference between the odds of advanced fibrosis and cirrhosis between groups. However, viral hepatitis steatotic liver disease individuals were found to have a significantly higher odds of clinically significant fibrosis (OR: 3.76, 95% CI, 1.27-11.14, p =0.02) compared with nonalcoholic steatotic liver disease. CONCLUSIONS: The current analysis assessed the proposed changes based on discussions from the consensus meeting. Although the definitions are an interim analysis of discussions, steatotic liver disease respects the underlying liver etiology and reduces stigma while increasing awareness of FL among viral and alcohol-associated steatosis/steatohepatitis.

Acute hepatitis of unknown origin in children: Behind the statistics.

Since April 2022, the world has been witnessing a rapidly spreading outbreak of acute hepatitis of unknown origin in children < 16 years old that has affected several countries around the world. Most of the cases have presented with the clinical picture of severe hepatitis that has led to resorting to liver transplantation in several cases. Despite the numerous theories that have been suggested on the possible underlying etiologies of the outbreak, an association with hepatitis A-E viruses and a link to COVID-19 vaccines have been excluded. Adenovirus serotype 41 has been detected in numerous cases, which makes it the most likely underlying cause of the disease. Nevertheless, other hypotheses are being investigated to justify the severity of the clinical picture, which is not typical of this type of virus. This review aims to summarize the current knowledge about the outbreak, highlight the suggested working hypotheses, and report the public health measures undertaken to tackle the outbreak.

Clinical characteristics of hepatitis-associated aplastic anemia in children.

To understand the current situation of hepatitis-related aplastic anemia (HAAA) in children, we analyzed the patients with HAAA admitted to our hospital in the past 5 years to understand the disease characteristics and prognosis. The clinical data of patients with HAAA admitted to our hospital from February 2017 to May 2022 were retrospectively analyzed. A total of 81 patients with HAAA, 56 males and 25 females. The median onset age was 5.9 years. The median time from hepatitis to occurrence of hemocytopenia was 30 days, and the median follow-up time was 2.77 years. There were 23 cases (28.5%) of severe aplastic anemia (SAA), 50 cases of very severe aplastic anemia (VSAA), and 8 cases of non-severe aplastic anemia (NSAA). At the beginning of the disease, cytotoxic T lymphocyte (CTL) was higher than normal in 60% of patients, and the median CD4/CD8 ratio was 0.2. As of follow-up, 72 children survived, 4 were lost, and 5 died. Thirty-four cases were treated with immunosuppressive therapy (IST), with a median follow-up time of 0.97 years. The total reaction rate was 73.5% (25/34), the complete reaction rate was 67.6% (23/34), and the nonreaction rate was 26.5% (9/34). Multivariate analysis suggested that co-infection was an independent risk factor affecting the efficacy of IST at 6 months, with an OR value of 16.76, 95% CI (1.23, 227.95), P=0.034. No independent influencing factors were found at the end of follow-up. The proportion of CTL cells in peripheral blood of children with HAAA is relatively increased, and IST is effective in 73.5% of children. Co-infection may prolongs the time to response to IST.

Hepatitis A Exposure Response and Outbreak Prevention in a Large Urban Jail - Los Angeles County, California, May-July 2023.

Correctional settings provide a high-risk environment for hepatitis A transmission because of the high proportion of homelessness and injection drug use among persons who are incarcerated. On May 30, 2023, Los Angeles County Department of Public Health informed the Communicable Disease Surveillance and Control (CDSC) unit of the Los Angeles County Jail system that a symptomatic incarcerated person had received a positive test result for acute hepatitis A. Upon learning the next day that the patient was a food handler, CDSC staff members identified 5,830 potential contacts of the index patient, 1,702 of whom had been released from the jail. During June 1-12, a total of 2,766 contacts who did not have a documented history of hepatitis A serology or vaccination that could be confirmed from the electronic health record or state immunization registry were identified. These persons were offered hepatitis A vaccination as postexposure prophylaxis; 1,510 (54.6%) accepted vaccination. Contacts who were food handlers without confirmed evidence of immunity and who declined vaccination were removed from food-handling duties for the duration of their potential incubation period. No additional cases were identified. Identifying contacts promptly and using immunization and serology records to ensure rapid delivery of postexposure prophylactic vaccine can help prevent hepatitis A transmission during exposures among incarcerated populations.

Decreasing parvovirus B19 and hepatitis A nucleic acid test positivity rates in Canadian plasma donors following the initiation of COVID-19 restriction in March 2020.

BACKGROUND AND OBJECTIVES: In Canada, plasma sent for fractionation is tested for both parvovirus B19 (B19V) and hepatitis A virus (HAV). This study compared positivity rates of B19 and HAV nucleic acid tests (NATs) in Canadian plasma samples for the pre-COVID-19 restriction era (2015 to end of February 2020 [Q1] 2020) and the post-COVID-19 restriction era. MATERIALS AND METHODS: Pooled EDTA plasma specimens were tested within 24 months of blood draw using the Procleix Panther System (Grifols Diagnostic Solutions Inc, San Diego, CA, USA) for B19V and HAV detection. Reactive pools were resolved by individual specimen testing. RESULTS: Between 1 January 2015, and 31 March 2022, 3,928,619 specimens from Canadian plasma donors were tested for B19V. For the same period, 3,922,954 specimens were tested for HAV. To account for a lag in specimen testing for up to 24 months, the data were divided into: (1) a pre-pandemic period (1 January 2015-31 March 2020; B19V tested n = 2,412,701, B19V NAT-positive n = 240 [0.01%], HAV tested n = 2,407,036, HAV NAT-positive n = 26 [0.001%]); (2) a two-year mixed-impact period (1 April 2020-31 March 2022; B19V tested n = 968,250, B19V NAT-positive n = 14 [0.001%], HAV tested n = 968,250, HAV NAT-positive n = 2 [0.0002%]); and (3) a pandemic-impact period (1 April 2022-31 March, 2023; B19V tested n = 597,668, B19V NAT-positive n = 3 [0.0005%], HAV tested n = 597,668, HAV NAT-positive n = 1 [0.0002%]). CONCLUSION: The percentage of B19V- and HAV-positive donations was significantly reduced from the pre-pandemic period to the pandemic-impact period.