High-level Viremia Research Articles

Tenofovir and Hepatitis B Virus Transmission During Pregnancy

ImportanceStandard care for preventing mother-to-child transmission (MTCT) of hepatitis B virus (HBV) in highly viremic mothers consists of maternal antiviral prophylaxis beginning at gestational week 28 combined with an HBV vaccine series and HBV immune globulin (HBIG) at birth. However, HBIG is unavailable in some resource-limited areas.ObjectiveTo determine whether initiating tenofovir disoproxil fumarate (TDF) at gestational week 16 combined with HBV vaccinations for infants is noninferior to the standard care of TDF at gestational week 28 combined with HBV vaccinations and HBIG for infants in preventing MTCT in mothers with HBV and high levels of viremia.Design, Setting, and ParticipantsAn unblinded, 2-group, randomized, noninferiority clinical trial was conducted in 7 tertiary care hospitals in China. A total of 280 pregnant individuals (who all identified as women) with HBV DNA levels greater than 200 000 IU/mL were enrolled between June 4, 2018, and February 8, 2021. The final follow-up occurred on March 1, 2022.InterventionsPregnant individuals were randomly assigned to receive either TDF starting at gestational week 16 with HBV vaccinations for the infant or TDF starting at gestational week 28 with HBV vaccinations and HBIG administered to the infant.Main Outcomes and MeasuresThe primary outcome was the MTCT rate, defined as detectable HBV DNA greater than 20 IU/mL or hepatitis B surface antigen positivity in infants at age 28 weeks. Noninferiority was established if the MTCT rate in the experimental group did not increase by more than an absolute difference of 3% compared with the standard care group, as measured by the upper limit of the 2-sided 90% CI.ResultsAmong 280 pregnant individuals who enrolled in the trial (mean age, 28 years; mean gestational age at enrollment, 16 weeks), 265 (95%) completed the study. Among all live-born infants, using the last observation carried forward, the MTCT rate was 0.76% (1/131) in the experimental group and 0% (0/142) in the standard care group. In the per-protocol analysis, the MTCT rate was 0% (0/124) in the experimental group and 0% (0/141) in the standard care group. The between-group difference was 0.76% (upper limit of the 2-sided 90% CI, 1.74%) in all live-born infants and 0% (upper limit of the 2-sided 90% CI, 1.43%) in the per-protocol analysis. Both comparisons met the criterion for noninferiority. Rates of congenital defects and malformations were 2.3% (3/131) in the experimental group and 6.3% (9/142) in the standard care group (difference, 4% [2-sided 95% CI, −8.8% to 0.7%]).Conclusions and RelevanceAmong pregnant women with HBV and high levels of viremia, TDF beginning at gestational week 16 combined with HBV vaccination for infants was noninferior to the standard care of TDF beginning at gestational week 28 combined with HBIG and HBV vaccination for infants. These results support beginning TDF at gestational week 16 combined with infant HBV vaccine to prevent MTCT of HBV in geographic areas where HBIG is not available.Trial RegistrationClinicalTrials.gov Identifier: NCT03476083

Advanced optimal control approaches for immune boosting and clinical treatment to enhance dengue viremia models using ABC fractional-order analysis.

This work focuses on the Dengue-viremia ABC (Atangana-Baleanu Caputo) fractional-order differential equations, accounting for both symptomatic and asymptomatic infected cases. Symptomatic cases are characterized by higher viremia levels, whereas asymptomatic cases exhibit lower viremia levels. The fractional-order model highlights memory effects and other advantages over traditional models, offering a more comprehensive representation of dengue dynamics. The total population is divided into four compartments: susceptible, asymptomatic infected, symptomatic infected, and recovered. The model incorporates an immune-boosting factor for asymptomatic infected individuals and clinical treatment for symptomatic cases. Positivity and boundedness of the model are validated, and both local and global stability analyses are performed. The novel Adams-Bash numerical scheme is utilized for simulations to rigorously assess the impact of optimal control interventions. The results demonstrate the effectiveness of the proposed control strategies. The reproduction numbers must be reduced based on specific optimal control conditions to effectively mitigate disease outbreaks. Numerical simulations confirm that the optimal control measures can significantly reduce the spread of the disease. This research advances the understanding of Dengue-viremia dynamics and provides valuable insights into the application of ABC fractional-order analysis. By incorporating immune-boosting and clinical treatment into the model, the study offers practical guidelines for implementing successful disease control strategies. The findings highlight the potential of using optimal control techniques in public health interventions to manage disease outbreaks more effectively.

Minimally Modified HIV-1 Infection of Macaques: Development, Utility, and Limitations of Current Models.

Nonhuman primate (NHP) studies that utilize simian immunodeficiency virus (SIV) to model human immunodeficiency virus (HIV-1) infection have proven to be powerful, highly informative research tools. However, there are substantial differences between SIV and HIV-1. Accordingly, there are numerous research questions for which SIV-based models are not well suited, including studies of certain aspects of basic HIV-1 biology, and pre-clinical evaluations of many proposed HIV-1 treatment, prevention, and vaccination strategies. To overcome these limitations of NHP models of HIV-1 infection, several groups have pursued the derivation of a minimally modified HIV-1 (mmHIV-1) capable of establishing pathogenic infection in macaques that authentically recapitulates key features of HIV-1 in humans. These efforts have focused on three complementary objectives: (1) engineering HIV-1 to circumvent species-specific cellular restriction factors that otherwise potently inhibit HIV-1 in macaques, (2) introduction of a C chemokine receptor type 5 (CCR5)-tropic envelope, ideally that can efficiently engage macaque CD4, and (3) correction of gene expression defects inadvertently introduced during viral genome manipulations. While some progress has been made toward development of mmHIV-1 variants for use in each of the three macaque species (pigtail, cynomolgus, and rhesus), model development progress has been most promising in pigtail macaques (PTMs), which do not express an HIV-1-restricting tripartite motif-containing protein 5 α (TRIM5α). In our work, we have derived a CCR5-tropic mmHIV-1 clone designated stHIV-A19 that comprises 94% HIV-1 genome sequence and replicates to high acute-phase titers in PTMs. In animals treated with a cell-depleting CD8α antibody at the time of infection, stHIV-A19 maintains chronically elevated plasma viral loads with progressive CD4+ T-cell loss and the development of acquired immune-deficiency syndrome (AIDS)-defining clinical endpoints. However, in the absence of CD8α+ cell depletion, no mmHIV-1 model has yet displayed high levels of chronic viremia or AIDS-like pathogenesis. Here, we review mmHIV-1 development approaches, the phenotypes, features, limitations, and potential utility of currently available mmHIV-1s, and propose future directions to further advance these models.

HOPE springs eternal: lack of HIV superinfection in HIV Organ Policy Equity Act kidney transplants.

Kidney transplantation from donors with HIV to recipients with HIV (HIV D+/R+) is an emerging practice that has shown substantial clinical benefit. Sustained HIV superinfection, whereby a transplant recipient acquires a new strain of HIV from their organ donor, is a theoretical risk, which might increase chances of viral failure. In this issue of the JCI, Travieso, Stadtler, and colleagues present phylogenetic analysis of HIV from kidney tissue, urine, plasma, and cells from 12 HIV D+/R+ kidney transplants out to five years of follow-up. Early after transplant, donor HIV was transiently detected in five of 12 recipients, primarily from donors with untreated HIV and high-level viremia, consistent with a viral inoculum. Long-term, donor HIV was not detected in any recipients, demonstrating no sustained HIV superinfection. These reassuring data support earlier findings from South Africa and the United States and further confirm the safety of HIV D+/R+ transplantation.

Distinct virologic trajectories in chronic hepatitis B identify heterogeneity in response to nucleos/tide analogue therapy

Background & AimsThe dynamics of HBV viral load (VL) in patients with chronic hepatitis B (CHB) on nucleos/tide analogue (NA) treatment and its relationship with liver disease are poorly understood. We aimed to study longitudinal VL patterns and their associations with CHB clinical outcomes. MethodsUtilising large scale, routinely collected electronic health records from six centres in England, collated by the National Institute for Health and Care Research Health Informatics Collaborative (NIHR HIC), we applied latent class mixed models to investigate VL trajectory patterns in adults receiving NA treatment. We assessed associations of VL trajectory with alanine transaminase (ALT), and with liver fibrosis/cirrhosis. ResultsWe retrieved data from 1885 adults on NA treatment (median follow-up 6.2 years, interquartile range (IQR) 3.7-9.3 years), with 21,691 VL measurements (median 10 per patient, IQR 5-17). Five VL classes were identified from the derivation cohort (n=1367, discrimination: 0.93, entropy: 0.90): class 1 ‘long term suppression’ (n=827, 60.5%), class 2 ‘timely virological suppression’ (n=254, 18.6%), class 3 ‘persistent moderate viraemia’ (n=140, 10.2%), class 4 ‘persistent high-level viraemia’ (n=44, 3.2%), and class 5 ‘slow virological suppression’ (n=102, 7.5%). The model demonstrated a discrimination of 0.93 and entropy of 0.88 for the validation cohort (n=518). ALT decreased variably over time in VL-suppressed groups (classes 1, 2, 5; all p<0.001), but did not significantly improve in those with persistent viraemia (classes 3, 4). Patients in class 5 had 2-fold increased hazards of fibrosis/cirrhosis compared to class 1 (adjusted hazard ratio, 2.00; 95% CI, 1.33-3.02). ConclusionsHeterogeneity exists in virological response to NA therapy in CHB patients, with over 20% showing potentially suboptimal responses. Slow virological suppression is associated with liver disease progression.

Symptomatic and Asymptomatic Neurocognitive Impairment, ART Adherence and HIV Control: A 4-Year Observational Study.

We assessed whether symptomatic neurocognitive impairment (NCI) and asymptomatic NCI -of which the clinical relevance is debated- affect HIV control and the role of ART adherence in this relationship. Observational study on the relationship between NCI and viral control during the 2 years before and the 2 after the neurocognitive evaluation (NCE) of 322 PLWH on ART. Viral load (VL) was defined as undetectable, very low-level (VLLV), low-level (LLV), or high-level viremia (HLV), and classified overtime as persistent (p; ≥2 consecutive values in the same worst category), viral failure (VF; ≥1 HLV requiring ART changes), or optimal control. Adherence was the proportion of days covered by ART. Frascati criteria were used. Adjusted models were performed for factors associated with viral control. Mediation analyses informed causality in the path from NCI to viral control through adherence. Sensitivity analyses were focused on the year following NCE for only participants with optimal viral control before. Among the participants (53 ± 10 years, CD4 + T-cells 630/µL), 41.6% and 10.8% presented asymptomatic and symptomatic NCI. Over 3,304 VLs, 8.4% and 22.1% of participants had VF and pLLV/pVLLV. Both symptomatic and asymptomatic NCI were independently associated with VF (aRRR = 8.5; aRRR = 4.3) and pVLLV/pLLV (aRRR = 4.3; aRRR = 2.1). Specific cognitive domains showed independent associations with VL categories (models' P < 0.001). Adherence partially mediated these relationships (models' P < 0.001). Sensitivity analysis confirmed these findings. Prevalence and severity of poor viral control increased as the severity of NCI increased, with ART adherence mediating this relationship. The current "asymptomatic" attribution used by Frascati's criteria could overlook clinical risks.

Dengue viremia kinetics and effects on platelet count and clinical outcomes: An analysis of 2340 patients from Vietnam.

Viremia is a critical factor in understanding the pathogenesis of dengue infection, but limited data exist on viremia kinetics. This study aimed to investigate the kinetics of viremia and its effects on subsequent platelet count, severe dengue, and plasma leakage. We pooled data from three studies conducted in Vietnam between 2000 and 2016, involving 2340 dengue patients with daily viremia measurements and platelet counts after symptom onset. Viremia kinetics were assessed using a random effects model that accounted for left-censored data. The effects of viremia on subsequent platelet count and clinical outcomes were examined using a landmark approach with a random effects model and logistic regression model with generalized estimating equations, respectively. The rate of viremia decline was derived from the model of viremia kinetics. Its effect on the clinical outcomes was assessed by logistic regression models. Viremia levels rapidly decreased following symptom onset, with variations observed depending on the infecting serotype. DENV-1 exhibited the highest mean viremia levels during the first 5-6 days, while DENV-4 demonstrated the shortest clearance time. Higher viremia levels were associated with decreased subsequent platelet counts from day 6 onwards. Elevated viremia levels on each illness day increased the risk of developing severe dengue and plasma leakage. However, the effect size decreased with later illness days. A more rapid decline in viremia is associated with a reduced risk of the clinical outcomes. This study provides comprehensive insights into viremia kinetics and its effect on subsequent platelet count and clinical outcomes in dengue patients. Our findings underscore the importance of measuring viremia levels during the early febrile phase for dengue studies and support the use of viremia kinetics as outcome for phase-2 dengue therapeutic trials. Wellcome Trust and European Union Seventh Framework Programme.

An mRNA-LNP-based Lassa virus vaccine induces protective immunity in mice.

The mammarenavirus Lassa virus (LASV) causes the life-threatening hemorrhagic fever disease, Lassa fever. The lack of licensed medical countermeasures against LASV underscores the urgent need for the development of novel LASV vaccines, which has been hampered by the requirement for a biosafety level 4 facility to handle live LASV. Here, we investigated the efficacy of mRNA-lipid nanoparticle (mRNA-LNP)-based vaccines expressing the LASV glycoprotein precursor (LASgpc) or nucleoprotein (LCMnp) of the prototypic mammarenavirus, lymphocytic choriomeningitis virus (LCMV), in mice. Two doses of LASgpc- or LCMnp-mRNA-LNP administered intravenously (i.v.) protected C57BL/6 mice from a lethal challenge with a recombinant (r) LCMV expressing a modified LASgpc (rLCMV/LASgpc2m) inoculated intracranially. Intramuscular (i.m.) immunization with two doses of LASgpc- or LCMnp-mRNA-LNP significantly reduced the viral load in C57BL/6 mice inoculated i.v. with rLCMV/LASgpc2m. High levels of viremia and lethality were observed in CBA mice inoculated i.v. with rLCMV/LASgpc2m, which were abrogated by i.m. immunization with two doses of LASgpc-mRNA-LNP. The protective efficacy of two i.m. doses of LCMnp-mRNA-LNP was confirmed in a lethal hemorrhagic disease model of FVB mice i.v. inoculated with wild-type rLCMV. In all conditions tested, negligible and high levels of LASgpc- and LCMnp-specific antibodies were detected in mRNA-LNP-immunized mice, respectively, but robust LASgpc- and LCMnp-specific CD8+ T cell responses were induced. Accordingly, plasma from LASgpc-mRNA-LNP-immunized mice did not exhibit neutralizing activity. Our findings and surrogate mouse models of LASV infection, which can be studied at a reduced biocontainment level, provide a critical foundation for the rapid development of mRNA-LNP-based LASV vaccines.IMPORTANCELassa virus (LASV) is a highly pathogenic mammarenavirus responsible for several hundred thousand infections annually in West African countries, causing a high number of lethal Lassa fever (LF) cases. Despite its significant impact on human health, clinically approved, safe, and effective medical countermeasures against LF are not available. The requirement of a biosafety level 4 facility to handle live LASV has been one of the main obstacles to the research and development of LASV countermeasures. Here, we report that two doses of mRNA-lipid nanoparticle-based vaccines expressing the LASV glycoprotein precursor (LASgpc) or nucleoprotein (LCMnp) of lymphocytic choriomeningitis virus (LCMV), a mammarenavirus genetically closely related to LASV, conferred protection to recombinant LCMV-based surrogate mouse models of lethal LASV infection. Notably, robust LASgpc- and LCMnp-specific CD8+ T cell responses were detected in mRNA-LNP-immunized mice, whereas no virus-neutralizing activity was observed.

Prevalence and risk factors of transmission of hepatitis delta virus in pregnant women in the Center Region of Cameroon.

Hepatitis B virus (HBV) and hepatitis delta virus (HDV) co-infection has been described as the most severe form of viral hepatitis, and can be co-transmitted from mother-to-child. A seroprevalence of 4.0% of HDV infection was reported in pregnant women in Yaoundé, and 11.9% in the general population in Cameroon. Our objective was to describe the rate of HDV infection in HBsAg-positive pregnant women and to determine risk factors associated with mother-to-child transmission of HDV. A cross-sectional, descriptive study was conducted from January 2019 to July 2022 among pregnant women attending antenatal contacts in seven health structures in the Centre Region of Cameroon. A consecutive sampling (non-probability sampling) was used to select only pregnant women of age over 21 years, who gave a written informed consent. Following an informed consent, an open-ended questionnaire was used for a Knowledge, Attitude and Practice (KAP) survey of these women, and their blood specimens collected and screened for HBsAg, anti-HIV and anti-HCV antibodies by rapid tests and ELISA. HBsAg-positive samples were further screened for HBeAg, anti-HDV, anti-HBs, and anti HBc antibodies by ELISA, and plasma HDV RNA load measured by RT-qPCR. Of 1992 pregnant women, a rate of 6.7% of HBsAg (133/1992) with highest rate in the rural areas, and 3.9% of hepatitis vaccination rate were recorded. Of 130, 42 (32.3%) were anti-HDV antibody-positive, and 47.6% had detectable HDV RNA viraemia. Of 44 anti-HDV-positive cases, 2 (4.5%) were co-infected with HBV and HCV, while 5 (11.4%) with HIV and HBV. Multiple pregnancies, the presence of tattoos and/or scarifications were significantly associated with the presence of anti-HDV antibodies. Of note, 80% of women with negative HBeAg and positive anti-HBe serological profile, had plasma HDV RNA load of more than log 3.25 (>10.000 copies/ml). These results show an intermediate rate of HDV infection among pregnant women with high level of HDV RNA viremia, which suggest an increased risk of vertical and horizontal co-transmission of HDV.

Identifying longitudinal patterns of HIV treatment (dis)engagement and re-engagement from oral histories of virologically unsuppressed persons in Uganda: A thematic trajectory analysis

BackgroundThere is limited study of persons deemed “harder to reach” by HIV treatment services, including those discontinuing or never initiating antiretroviral therapy (ART). We conducted narrative research in southern Uganda with virologically unsuppressed persons identified through population-based sampling to discern longitudinal patterns in HIV service engagement and identify factors shaping treatment persistence. MethodsIn mid-2022, we sampled adult participants with high-level HIV viremia (≥1000 RNA copies/mL) from the prospective, population-based Rakai Community Cohort Study. Using life history calendars, we conducted initial and follow-up in-depth interviews to elicit oral histories of participants’ journeys in HIV care, from diagnosis to the present. We then used thematic trajectory analysis to identify discrete archetypes of HIV treatment engagement by “re-storying” participant narratives and visualizing HIV treatment timelines derived from interviews and abstracted clinical data. ResultsThirty-eight participants (median age: 34 years, 68% men) completed 75 interviews. We identified six HIV care engagement archetypes from narrative timelines: (1) delayed ART initiation, (2) early treatment discontinuation, (3) treatment cycling, (4) prolonged treatment interruption, (5) transfer-related care disruption, and (6) episodic viremia. Patterns of service (dis)engagement were highly gendered, occurred in the presence and absence of optimal ART adherence, and were shaped by various factors emerging at different time points, including: denial of HIV serostatus and disclosure concerns; worsening HIV-related symptoms; psychological distress and depression; social support; intimate partner violence; ART side effects; accessibility constraints during periods of mobility; incarceration; and inflexible ART dispensing regulations. ConclusionsIdentified trajectories uncovered heterogeneities in both the timing and drivers of ART (re-)initiation and (dis)continuity, demonstrating the distinct characteristics and needs of people with different patterns of HIV treatment engagement throughout the life course. Enhanced mental health service provision, expanded eligibility for differentiated service delivery models, and streamlined facility switching processes may facilitate timely (re-)engagement in HIV services.

Incidence and predictors of elevated postpartum alanine aminotransferase in chronic hepatitis B mothers: a prospective study protocol

BackgroundThe majority of HBeAg-positive mothers with chronic hepatitis B have high levels of viremia and inactive disease with normal alanine aminotransferase (ALT) during pregnancy. In addition, postpartum disease activation and ALT flare have been reported in the range of 15 − 35%. However, the current International Association Guidelines have not provided clear recommendations and a risk-stratified monitoring schedule. Furthermore, data are lacking on the definition of normal ALT in the postpartum period in mothers with chronic hepatitis B. The clinical features and ALT flare patterns in HBeAg-positive mothers versus HBeAg-negative mothers are not fully explored. Thus, we design a cohort study to investigate the aforementioned area and generate data to assist healthcare providers in better managing mothers with hepatitis B. We aim to assess the frequency of postpartum ALT flares and predictors for such events.MethodThis study is a single-center and prospective cohort study (n = 360) that consists of two groups of patients including HBsAg-positive mothers (n = 120) and healthy mothers without HBV infection (n = 240). In HBeAg-positive mothers, antiviral therapy during late pregnancy is permitted to prevent Mother-to-child transmission (MTCT) but discontinued at delivery if there is no further indication for the treatment. Mothers are enrolled at the gestational weeks of 12–24. After delivery, both mothers and their infants will be followed up until postpartum week 24. Clinical and laboratory data are collected every 4 weeks during the study except there are no follow-up visits at the postpartum weeks 16 and 20. The primary objective is the proportion of patients with postpartum ALT flares. The secondary objectives are independent risk factors during pregnancy for predicting postpartum ALT flares and the normal range of postpartum ALT levels in healthy mothers.DiscussionThe current study focuses on the incidence of postpartum ALT flares in mothers with chronic hepatitis B including subgroup analysis based on HBeAg status. The data will have several clinical implications, such as providing evidence for an appropriate monitoring schedule in CHB mothers after delivery. Further analyses on predictors of such events may assist clinicians in identifying mothers who might develop severe postpartum ALT flares. The data generated from healthy mothers have the potential to identify the patterns of ALT changes during pregnancy and postpartum, so we can gain a better understanding of the normal range of ALT in this subpopulation.Trial Registration Number at the Chinese Clinical Trial RegistryChiCTR2200061130.

In Vivo and In Vitro Characterization of the Recently Emergent PRRSV 1-4-4 L1C Variant (L1C.5) in Comparison with Other PRRSV-2 Lineage 1 Isolates.

The recently emerged PRRSV 1-4-4 L1C variant (L1C.5) was in vivo and in vitro characterized in this study in comparison with three other contemporary 1-4-4 isolates (L1C.1, L1A, and L1H) and one 1-7-4 L1A isolate. Seventy-two 3-week-old PRRSV-naive pigs were divided into six groups with twelve pigs/group. Forty-eight pigs (eight/group) were for inoculation, and 24 pigs (four/group) served as contact pigs. Pigs in pen A of each room were inoculated with the corresponding virus or negative media. At two days post inoculation (DPI), contact pigs were added to pen B adjacent to pen A in each room. Pigs were necropsied at 10 and 28 DPI. Compared to other virus-inoculated groups, the L1C.5-inoculated pigs exhibited more severe anorexia and lethargy, higher mortality, a higher fraction of pigs with fever (>40 °C), higher average temperature at several DPIs, and higher viremia levels at 2 DPI. A higher percentage of the contact pigs in the L1C.5 group became viremic at two days post contact, implying the higher transmissibility of this virus strain. It was also found that some PRRSV isolates caused brain infection in inoculation pigs and/or contact pigs. The complete genome sequences and growth characteristics in ZMAC cells of five PRRSV-2 isolates were further compared. Collectively, this study confirms that the PRRSV 1-4-4 L1C variant (L1C.5) is highly virulent with potential higher transmissibility, but the genetic determinants of virulence remain to be elucidated.

Prevalence of HIV drug resistance among adolescents receiving ART in Cameroon with low- or high-level viraemia.

To characterize HIV drug resistance (HIVDR) below and above the WHO threshold of 1000 copies/mL, considered for the definition of HIV ART failure in resource-limited settings. From a cohort of 280 adolescents (aged 10-19 years) receiving ART for at least 6 months, genotypic resistance testing (GRT) was attempted for two groups of participants: participants with low-level viraemia [LLV; viral load (VL) 200-999 copies/mL] and those in virological failure (VF; confirmed VL ≥1000 copies/mL) using an in-house method. The Stanford HIValg Program was used to identify relevant HIVDR mutations and predict the efficacy of the newly introduced tenofovir-lamivudine-dolutegravir combination. GRT was successfully performed in 54/58 (93.1%) eligible participants, of which 28/31 (90.3%) were in VF and 26/27 (96.3%) had LLV. A high level of resistance was found both in adolescents with LLV and those in VF, with respectively 84.6% (22/26) and 75.0% (21/28) of participants harbouring at least one HIVDR mutation. NRTIs and NNRTIs were the most affected drug classes in both population groups. In contrast, PIs were not significantly affected and dolutegravir was expected to be active for all participants tested. However, for the newly introduced dolutegravir-based combination, functional monotherapy (dolutegravir only) was potentially possible for 22.7% (5/22) of the participants with LLV. Our findings show that the 1000 copies/mL threshold is not an indicator of virological success and we call for a revision of the current WHO definition of VF in resource-limited countries.

A Triple Gene-Deleted Pseudorabies Virus-Vectored Subunit PCV2b and CSFV Vaccine Protect Pigs against a Virulent CSFV Challenge.

Classical swine fever (CSF) remains one of the most economically significant viral diseases affecting domestic pigs and wild boars worldwide. To develop a safe and effective vaccine against CSF, we have constructed a triple gene-deleted pseudorabies virus (PRVtmv)-vectored bivalent subunit vaccine against porcine circovirus type 2b (PCV2b) and CSFV (PRVtmv+). In this study, we determined the protective efficacy of the PRVtmv+ against virulent CSFV challenge in pigs. The results revealed that the sham-vaccinated control group pigs developed severe CSFV-specific clinical signs characterized by pyrexia and diarrhea, and became moribund on or before the seventh day post challenge (dpc). However, the PRVtmv+-vaccinated pigs survived until the day of euthanasia at 21 dpc. A few vaccinated pigs showed transient diarrhea but recovered within a day or two. One pig had a low-grade fever for a day but recovered. The sham-vaccinated control group pigs had a high level of viremia, severe lymphocytopenia, and thrombocytopenia. In contrast, the vaccinated pigs had a low-moderate degree of lymphocytopenia and thrombocytopenia on four dpc, but recovered by seven dpc. Based on the gross pathology, none of the vaccinated pigs had any CSFV-specific lesions. Therefore, our results demonstrated that the PRVtmv+ vaccinated pigs are protected against virulent CSFV challenge.

Baseline Cytomegalovirus Viremia at Cryptococcal Meningitis Diagnosis Is Associated With Long-term Increased Incident TB Disease and Mortality in a Prospective Cohort of Ugandan Adults With HIV.

Adults with HIV-associated cryptococcal meningitis have overlapping burdens of cytomegalovirus (CMV) and tuberculosis (TB) coinfections. CMV infection/reactivation is strongly associated with CMV-specific memory T-cell activation and upregulation of type 1 interferons, which may lead to increased risk of TB disease and poor outcomes. We conducted a cohort study of 2-week survivors of cryptococcal meningitis during 2010-2021 to determine TB incidence and all-cause mortality over time stratified by baseline CMV status. We followed 497 Ugandans with HIV-associated cryptococcal meningitis for a median (interquartile range) of 4.6 (2.6-53.9) months. Overall, 42% (210/497) developed incident TB disease or died. One-fifth (98/497, 19.7%) developed incident TB disease, and 29% (142/497) of participants died during follow-up. Of 259 participants with CMV viral load measured at baseline, 37% (96/259) had concurrent CMV viremia (defined as anyone with detectable CMV DNA in plasma/serum by qualitative polymerase chain reaction [PCR] detection). Of 59 with measured CMV immunoglobulin G (IgG), 100% had positive CMV IgG antibody serology (≥10 enzyme-linked immunosorbent assay units/mL). CMV viremia was positively associated with higher HIV viral load (196 667 vs 73 295 copies/mL; P = .002) and higher cerebrospinal fluid fungal burden (68 500 vs 14 000 cfu/mL; P = .002) compared with those without. Participants with high-level CMV viremia (defined as CMV viral load ≥1000 IU/mL) had twice the risk of incident TB (subdistribution adjusted hazard ratio [aHR], 2.18; 95% CI, 1.11-4.27) and death (aHR, 1.99; 95% CI, 1.14-3.49) compared with participants with no or low-level CMV viremia. There was no association between the CMV IgG index and the incidence of TB/death (P = .75). CMV viremia >1000 IU/mL at meningitis diagnosis was associated with increased incident TB disease and mortality during long-term follow-up. Future studies to determine the causal relationship and potential for therapeutic intervention are warranted.

Effects of Enhance Adherence Counselling on Viral Load Suppression Among High Viral Load HIV Seropositive Patients in a Nigerian Tertiary Health Facility

Background: EAC helps clients overcome adherence hurdles and improve ART adherence. This study examines the effect of EAC on viral load suppression. Method: This quantitative study aims to determine the impacts of enhanced adherence counselling (EAC) on viral load in Defence Headquarters Medical Center, Abuja, Nigeria. The medical records of HIV clients on ART included in EAC were extracted from the hospital and analyzed to determine the impacts of EAC on viral loads suppression of clients in the program. Result: Almost half of the PLWHIV in EAC have been on ART for 6-10 years (47.6%), 42.9% for more than ten years, and 9.5% have been on ART for 1 – 5 years. 76.2% of respondents were on the 1st line of the ART regimen, while 23.8% were on the 2nd line. 97.6% of clients enrolled for EAC were at the WHO stage I HIV infection, and only one (2.4%) was in stage IV. 50% tested for viral load was due to viral blip, 28.6% due to unsuppressed viral load and 21.4% were tested to monitor their VL. Furthermore, of the 33 clients with viral load results, 14 (42.4%) had very low-level viremia (&lt;50 copies/ml), 10 (30.3%) had low-level viremia (50–1000 copies/ml), but 9 (27.3%) still had high-level viremia (&gt;1000 copies/ml). 42.9% enrolled for EAC because of pill burdens, 31.0% due to irregular dosing frequency, 19.0% because of pill social problems, and 2.1% were people lost to follow-up returned.. Keywords: Antiretroviral therapy, EAC, Viral load.

γδ T cells mediate protective immune responses following an insect virus-based Chikungunya virus chimera vaccine

Abstract Chikungunya virus (CHIKV) is a re-emerging alphavirus that causes acute chikungunya fever (CHIKF) which often is accompanied by severe and persistent arthralgia. There are currently no licensed human vaccines against CHIKV. Eilat virus (EILV), a mosquito-specific alphavirus, replicates well in mosquito cells, but not in vertebrate cells. EILV/CHIKV is a chimeric CHIKV vaccine candidate that contains the nonstructural proteins of EILV and the structural proteins of CHIKV. This chimera vaccine candidate has been shown to protect against wild-type (WT) CHIKV challenge in mice and non-human primates (NHPs), yet the immune mechanism of the vaccine-induced host protection remains unknown. γδ T cells are known to react to WT CHIKV infection by controlling CHIKV inflammation, cell infiltration, and tissue damage. We found that γδ T cells are expanded following vaccination with EILV/CHIKV. TCRδ −/−mice, which are deficient of γδ T cells, exhibited a reduced CD8 +T cell effector function response at different timepoints compared to WT mice. This reduced CD8 +T cell response was also observed 7 days post WT CHIKV infection in the vaccinated mice. A significant reduction of CHIKV-specific IgM titers was also observed 7 days post WT CHIKV challenge in the vaccinated mice. Lastly, we noted that the vaccinated TCRδ −/−mice had higher levels of viremia than vaccinate WT mice following challenge with WT CHIKV. Overall, our results suggest that γδ T cells contribute to the host protection by promoting vaccine induced CD8 +T cell and antibody responses against CHIKV infection.

Evaluation of NS4A, NS4B, NS5 and 3'UTR Genetic Determinants of WNV Lineage 1 Virulence in Birds and Mammals.

West Nile virus (WNV) is amplified in an enzootic cycle involving birds as amplifying hosts. Because they do not develop high levels of viremia, humans and horses are considered to be dead-end hosts. Mosquitoes, especially from the Culex genus, are vectors responsible for transmission between hosts. Consequently, understanding WNV epidemiology and infection requires comparative and integrated analyses in bird, mammalian, and insect hosts. So far, markers of WNV virulence have mainly been determined in mammalian model organisms (essentially mice), while data in avian models are still missing. WNV Israel 1998 (IS98) is a highly virulent strain that is closely genetically related to the strain introduced into North America in 1999, NY99 (genomic sequence homology > 99%). The latter probably entered the continent at New York City, generating the most impactful WNV outbreak ever documented in wild birds, horses, and humans. In contrast, the WNV Italy 2008 strain (IT08) induced only limited mortality in birds and mammals in Europe during the summer of 2008. To test whether genetic polymorphism between IS98 and IT08 could account for differences in disease spread and burden, we generated chimeric viruses between IS98 and IT08, focusing on the 3' end of the genome (NS4A, NS4B, NS5, and 3'UTR regions) where most of the non-synonymous mutations were detected. In vitro and in vivo comparative analyses of parental and chimeric viruses demonstrated a role for NS4A/NS4B/5'NS5 in the decreased virulence of IT08 in SPF chickens, possibly due to the NS4B-E249D mutation. Additionally, significant differences between the highly virulent strain IS98 and the other three viruses were observed in mice, implying the existence of additional molecular determinants of virulence in mammals, such as the amino acid changes NS5-V258A, NS5-N280K, NS5-A372V, and NS5-R422K. As previously shown, our work also suggests that genetic determinants of WNV virulence can be host-dependent.

Functional Cure of Chronic Hepatitis B with Antiviral Treatment in Children having High-level Viremia and Normal or Mildly Elevated Serum Aminotransferase.

There is a lack of data supporting the notion that antiviral treatments can benefit children with chronic hepatitis B (CHB) having high viremia and normal or mildly elevated serum alanine aminotransferase (ALT) levels. We aimed to analyze the efficacy of antiviral treatments in children with CHB and explore the factors associated with functional cure. Forty-eight children with CHB having high viremia and normal or mildly elevated serum ALT levels were screened in this real-world study. Thirty-two children received either interferon-alpha (IFN-α) monotherapy, IFN-α therapy with a nucleoside analog (NA) add-on, or IFN-α and NA combination therapy. The 16 children in the control group did not receive antiviral treatment. All 48 children were available for follow-up assessments for the entire 36-month study period. We identified a functional cure with respect to hepatitis B virus (HBV) DNA loss, loss /seroconversion of circulating hepatitis B e antigen (HBeAg), and loss of hepatitis B surface antigen (HBsAg) with or without seroconversion. Cox regression analysis was employed to evaluate the factors that may have influenced the functional cure. After 36 months, the cumulative functional cure rate was 56.25% (18/32) in the treated group and 0% (0/16) in the control group (p<0.001). In the treated group, the serum HBV DNA levels declined rapidly at the end of a 6-month visit and the cured children achieved a loss rate of 100% (18/18) within 16 months of beginning treatment, compared with 64.29% (9/14) of the uncured children (p<0.001). The rates of HBeAg seroconversion were significantly higher among the cured children than among the uncured children (p<0.001). All 16 children in the control group maintained high levels of serum HBV DNA and were positive for both serum HBeAg and HBsAg during the entire 36 months of the study period. Functional cure was associated with younger ages (1-6 vs. 7-14 years, p=0.013), CD8+ T lymphocyte counts (p=0.013), and B lymphocyte counts (p=0.003). No serious adverse events were observed. Antiviral treatment achieved a functional cure of CHB in a high proportion of children having high-level viremia and normal or mildly elevated ALT levels. Younger age and high peripheral lymphocyte counts were associated with this functional cure.

Genomic Characterization and Pathogenicity of BJEU06-1-Like PRRSV-1 ZD-1 Isolated in China

Porcine reproductive and respiratory syndrome virus (PRRSV)-1 and PRRSV-2 have long been cocirculating in China. To date, all PRRSV-1 strains in China have been classified as subtype 1. We investigated the prevalence of PRRSV-1 in several areas of China from 2016 to 2022 and found that BJEU06-1-like strains comprised the main epidemic branch of PRRSV-1. Pathogenicity data for this subgroup are currently lacking. In this study, the Chinese BJEU06-1-like PRRSV-1 strain ZD-1 was isolated from primary alveolar macrophages (PAMs). ZD-1 has undergone no recombination and has a 5-aa discontinuous deletion in the Nsp2 protein, similar to other BJEU06-1-like strains; additionally, ZD-1 has a 26 aa C-terminal truncation in the GP3 gene. Pathogenicity studies revealed that ZD-1 causes obvious clinical symptoms: prolonged fever; reduced body weight; alveolar epithelial proliferation and moderate alveolar diaphragm widening in the lungs; diffuse lymphocytic hyperplasia in the lymph nodes; high levels of viremia in the serum; and elevated viral loads in the lungs, lymph nodes, and tonsils. These results suggested that the BJEU06-1-like PRRSV-1 strain ZD-1 is moderately pathogenic to piglets. This is the first study to evaluate the pathogenicity of the BJEU06-1-like branch in China, enriching the understanding of PRRSV-1 in China.