The Journal of Infectious Diseases

BackgroundTuberculosis (TB) is a leading cause of morbidity and mortality among children living with HIV (CLHIV). Poor diagnostic performance is a significant contributor. Serological assays that determine levels of Mycobacterium tuberculosis reactive antibodies inconsistently detect TB. However, antigen-specific antibody Fc receptor engagement and effector functions are promising biomarkers of TB disease. MethodsThis study evaluated serum from a well-characterized cohort of Kenyan CLHIV via tw...

BackgroundElimination of Plasmodium vivax is challenging due to its dormant liver stages (hypnozoites), which can reactivate weeks or months after the primary infection, causing relapses and ongoing transmission of the parasite. Despite these challenges, P. vivax clinical case numbers have declined over the past decade in Cambodia. We used parasite genotyping to assess whether the decline in case numbers was reflected in parasite diversity and relatedness as a proxy to transmission. MethodsGeno...

BackgroundSerotype 3 (S3) has remained a major cause of invasive pneumococcal disease (IPD) despite its inclusion in 13-valent pneumococcal conjugate vaccine (PCV). In October 2023, a 15-valent PCV (PCV15) including S3 was introduced into the Catalan universal childhood immunization program. MethodsWe conducted a retrospective pre-post surveillance study to compare pediatric IPD incidence in Catalonia during a pre-PCV15 period (October 1, 2022-September 30, 2023) and two post-PCV15 periods (Oct...

Dengue virus (DENV), comprising four distinct serotypes (DENV-1 to DENV-4), poses a major public health challenge in tropical regions. Infection with one serotype confers long-term immunity to that serotype alone, while subsequent heterologous infections are associated with increased risk of severe disease, necessitating vaccines that induce durable, balanced immunity across all serotypes. However, achieving such balance immunity remains a central challenge for dengue vaccine development. Using ...

BackgroundTuberculosis (TB) and HIV co-infection cause profound immune dysregulation. Understanding how these infections alter immune cell distribution across systemic and tissue compartments is critical for improving therapeutic and vaccine strategies. MethodsFlow cytometry was used to quantify CD4 and CD8 T cells, B cells, and tissue-resident memory (TRM) T and B cells in peripheral blood mononuclear cells (PBMCs), lung tissue, bronchoalveolar lavage (BAL), spleen, and lung-draining hilar lym...

Clade 2.3.4.4b highly pathogenic avian influenza A(H5N1) viruses continue to expand geographically and across mammalian hosts, raising concern about pandemic potential. The degree and specificity of pre-existing immunity in humans are key determinants of this risk. We analyzed hemagglutinin (HA)-and neuraminidase (NA)-specific antibody responses in 300 sera collected from adults in New York City. While HA directed binding antibodies to clade 2.3.4.4b H5 were low and hemagglutination-inhibiting a...

AO_SCPLOWBSTRACTC_SCPLOWInfluenza A subclade K viruses caused high infection rates in the 2025/2026 Northern Hemisphere season, raising concerns about antigenic drift and reduced vaccine effectiveness. We measured antibody responses in matched human pre- and post-vaccination sera against a vaccine-like as well as subclade K isolates. Pre-existing immunity to subclade K variants was noted with seasonal influenza vaccination boosting titers two-fold against subclade K and three-fold against the va...

BackgroundImmunocompromised (IC) individuals are at increased risk for persistent SARS-CoV-2 infections and can develop new viral mutations and lineages not seen in the community. In this case report, a persistent SARS-CoV-2 infection (330 days) in an IC patient is examined for viral mutations and mutations associated with cryptic lineages. Case PresentationThe patient was followed in a longitudinal study examining persistent SARS-CoV-2 in IC patients. The patient provided stool and nasal swab ...

BackgroundHeartland virus (HRTV) is an emerging tick-borne virus capable of causing severe illness and death. The burden of disease is likely underestimated due to limited seroprevalence studies, lack of commercially available diagnostic tests, and an overlapping clinical syndrome with more commonly diagnosed bacterial diseases such as spotted fever group rickettsiosis or ehrlichiosis. MethodsActive surveillance for Heartland virus disease was conducted at a large academic center from March to ...

Persistent, asymptomatic Plasmodium infections are common in areas of high transmission due to acquired immunity. When asymptomatically infected individuals seek care for a fever caused by something other than malaria parasites, they may test positive for parasites and be incorrectly diagnosed as having clinical malaria. This study used distributions of qPCR parasite densities to estimate the fraction of fever attributable to malaria (malaria attributable fraction, MAF) in a cohort of 659 indivi...

This exploratory analysis of PAX LC, a Phase 2, 1:1 randomized, double-blind, superiority, placebo-controlled trial examined whether treatment with nirmatrelvir/ritonavir (NMV/r) versus placebo/ritonavir (PBO/r) in individuals with Long COVID could reveal immune features associated with symptom improvement. Eighty-two participants (n=45 PBO/r; n=37 NMV/r) provided blood samples at baseline (Day 0) and post-treatment (Day 28). Baseline demographic and immunological phenotypes were similar in the ...

Immune imprinting, also known as immune history, is a core aspect of adaptive immunity that influences antibody responses to future antigen exposures. Nevertheless, the impact of sequential flavivirus vaccinations on epitope targeting and antibody activity in humans remains incompletely understood. This question is particularly important in regions where the inactivated Japanese encephalitis virus (JEV) vaccines and the live-attenuated dengue virus (DENV) vaccines are used, as both have been ass...

Serological surveillance is fundamental to infectious disease research and informed public-health decision making. Immunoassays used in the study of pathogen-specific immunity have historically relied on the collection of venous blood. While critical for many public-health applications, this sample collection method is invasive and resource intensive. The costs and logistical barriers associated with venous blood collection are exacerbated in resource-limited regions, and the shift to less invas...

A number of vaccines and long-acting monoclonal antibodies have been shown to be effective in the prevention of respiratory syncytial virus (RSV) disease. However, an immune correlate of protection for RSV has not yet been identified. We conducted a systematic review to identify published reports of immunogenicity and/or efficacy in vaccines and long-acting monoclonal antibodies against RSV and performed a meta-analysis on extracted data to identify any relationship between antibody increase and...

Incidence patterns of post-acute sequelae, characterised by persistence or delayed onset after the acute phase of an infection, are not well documented after infectious disease outbreaks. Nipah virus was first detected in the 1998-1999 Malaysia outbreak and remains a significant public health concern due to its high epidemic potential and recurrent outbreaks in South Asia. We conducted a systematic review on the prevalence, incidence, duration, and characteristics of post-acute sequelae in survi...

ObjectiveThis study investigates the prevalence of human pegivirus (HPgV) in SARS-CoV-2-positive patients within the context of viral co-infections that may modulate COVID-19 outcomes and assesses whether HPgV co-infection is associated with COVID-19 severity. HPgV is a widely circulating but rarely monitored human virus with documented immunomodulatory effects in other viral infections, including HIV and Ebola. While HPgV prevalence is low in the general U.S. population (1-2%), it rises markedl...

BackgroundMaintaining viral suppression among people who inject drugs (PWID) living with HIV in sub-Saharan Africa remains critical to minimize drug resistance for dolutegravir (DTG)-based regimens. We evaluated PWID taking DTG to assess longitudinal rates of viral non-suppression and emergence of drug resistance mutations in Kenya. MethodsWe enrolled Kenyan PWID who had transitioned from an efavirenz (EFV) based regimen to tenofovir+lamivudine+DTG (TLD) [≥]6 months prior, and measured plasm...

BackgroundClostridium perfringens can cause life-threatening extraintestinal infections in immunocompromised patients, an area in which we have little information regarding strain factors that impact patient risks and outcomes. MethodsWe conducted genomic-epidemiologic analyses on C. perfringens isolates from 70 patients seen at Brigham and Womens Hospital over 2021-2024. Genomic analyses evaluated strain profiles within a broader context of 2,321 C. perfringens genomes from foodborne, veterina...

ImportanceRecent reports have highlighted an intense influenza activity related to the circulation of the influenza A(H3N2) subclade k variant. There is no data available on the impact of the emergence of H3N2 subclade k on the severity of the 2025-2026 epidemic or on the clinical phenotype of patients requiring admission to the intensive care unit (ICU). ObjectiveTo compare the clinical presentation, hospital mortality and virological characteristics of patients with laboratory-confirmed influ...

Newly emerging influenza virus strains pose a constant threat as they encounter a population lacking neutralizing antibodies against the new strain. However, cross-reactive non-neutralizing antibodies (nnABs) may be present and assist in mitigating disease symptoms via various effector mechanisms, including antibody-dependent cellular cytotoxicity (ADCC). Although nnABs to influenza virus have received more attention lately, little information is available on their age-related prevalence, steady...