Geographical migration and fitness dynamics of Streptococcus pneumoniae.

Streptococcus pneumoniae is a leading cause of pneumonia and meningitis worldwide. Many different serotypes co-circulate endemically in any one location1,2. The extent and mechanisms of spread and vaccine-driven changes in fitness and antimicrobial resistance remain largely unquantified. Here using geolocated genome sequences from South Africa (n = 6,910, collected from 2000 to 2014), we developed models to reconstruct spread, pairing detailed human mobility data and genomic data. Separately, we estimated the population-level changes in fitness of strains that are included (vaccine type (VT)) and not included (non-vaccine type (NVT)) in pneumococcal conjugate vaccines, first implemented in South Africa in 2009. Differences in strain fitness between those that are and are not resistant to penicillin were also evaluated. We found that pneumococci only become homogenously mixed across South Africa after 50 years of transmission, with the slow spread driven by the focal nature of human mobility. Furthermore, in the years following vaccine implementation, the relative fitness of NVT compared with VT strains increased (relative risk of 1.68; 95% confidence interval of 1.59-1.77), with an increasing proportion of these NVT strains becoming resistant to penicillin. Our findings point to highly entrenched, slow transmission and indicate that initial vaccine-linked decreases in antimicrobial resistance may be transient.

Post-acute sequelae of SARS-CoV-2 infection in health care workers from South Africa.

Health care workers (HCWs) are primary health providers therefore ensuring their protection and recovery from Covid-19 is of high interest. We investigated post-acute sequelae of SARS-CoV-2 infection (PASC) in HCWs who had previously been infected with SARS-CoV-2. Overall, 68 HCWs were classified as PASC according to duration of persisting symptoms. The 68 HCWs with PASC were split into two groups according to the mean duration of their symptoms, which were (8 PASC) 122 and (60 PASC) 641 days. The frequencies of common symptoms reported by HWCs with PASC were continuous headaches (45), mild cough (41), fatigue (37), myalgia (25) and shortness of breath (14). When using the Medical Research Council (MRC) dyspnoea scale to examine the degree of breathlessness in relations to activity we found that 4 reported having difficulty breathing after strenuous exercise, 19 were identified with shortness of breath when walking fast or when walking up a slight hill, 2 reported walking slower than most people on level or stopping after 15 minutes walking at own pace, 1 reported stopping to breath after walking 91 meters, or after a few minutes on level ground and 1 reported being too breathless to leave the house, or breathless when dressing/undressing. Our results highlight concern for HCWs with long-term persisting symptoms which may negatively impact their health this represents an emerging public health priority. HCWs with prolonged Covid-19 symptoms especially breathing difficulties need better diagnostic tests and treatments.

Hemagglutinin stalk-specific Fc-mediated functions are associated with protection against influenza-illness after seasonal influenza vaccination in pregnant women.

BACKGROUND: Several influenza vaccine candidates aim to elicit antibodies against the conserved hemagglutinin stalk domain. Understanding the protective mechanism of these antibodies, which mediate broad neutralization and Fc-mediated functions, following seasonal vaccination is critical. METHODS: Plasma samples were obtained from a subset of pregnant women living with or without HIV-1 enrolled in a randomised trial (138 trivalent inactivated vaccine [TIV] and 145 placebo recipients). Twenty-three influenza-illness cases were confirmed within 6 months postpartum. We measured H1 stalk-specific antibody-dependent cellular phagocytosis (ADCP), complement deposition (ADCD) and cellular cytotoxicity (ADCC) at enrolment and 1-month post-vaccination. The association between these Fc-mediated functions and protection against influenza-illness following vaccination was examined using multiple logistic regression analysis and risk reduction thresholds were defined by the score associated with the lowest odds of influenza-illness. RESULTS: Amongst TIV and placebo recipients, lower H1 stalk-specific ADCP and ADCD activity was detected for participants with confirmed influenza compared with individuals without confirmed influenza-illness 1-month post-vaccination. Pre-existing ADCP scores ≥250 reduced the odds of A/H1N1 infection (odds ratio 0.11; p=0.01) with an 83% likelihood of risk reduction. Following TIV, ADCD scores of ≥25 and ≥15 significantly reduced the odds against A/H1N1 (0.10; p=0.01) and non-group 1 (0.06; p=0.0004) influenza virus infections, respectively. These ADCD scores were associated with >84% likelihood of risk reduction. H1 stalk-specific ADCC potential was not associated with protection against influenza-illness. CONCLUSION: H1 stalk-specific ADCD correlates with protection against influenza-illness following influenza vaccination during pregnancy. These findings provide insight into the protective mechanisms of HA stalk antibodies.

High-resolution African HLA resource uncovers HLA-DRB1 expression effects underlying vaccine response.

How human genetic variation contributes to vaccine effectiveness in infants is unclear, and data are limited on these relationships in populations with African ancestries. We undertook genetic analyses of vaccine antibody responses in infants from Uganda (n = 1391), Burkina Faso (n = 353) and South Africa (n = 755), identifying associations between human leukocyte antigen (HLA) and antibody response for five of eight tested antigens spanning pertussis, diphtheria and hepatitis B vaccines. In addition, through HLA typing 1,702 individuals from 11 populations of African ancestry derived predominantly from the 1000 Genomes Project, we constructed an imputation resource, fine-mapping class II HLA-DR and DQ associations explaining up to 10% of antibody response variance in our infant cohorts. We observed differences in the genetic architecture of pertussis antibody response between the cohorts with African ancestries and an independent cohort with European ancestry, but found no in silico evidence of differences in HLA peptide binding affinity or breadth. Using immune cell expression quantitative trait loci datasets derived from African-ancestry samples from the 1000 Genomes Project, we found evidence of differential HLA-DRB1 expression correlating with inferred protection from pertussis following vaccination. This work suggests that HLA-DRB1 expression may play a role in vaccine response and should be considered alongside peptide selection to improve vaccine design.

Distributions of candidate vaccine Targets, virulence Factors, and resistance features of invasive group B Streptococcus using Whole-Genome Sequencing: A Multicenter, population-based surveillance study.

BACKGROUND: Group B Streptococcus (GBS) is a leading cause of morbidity and mortality in young infants worldwide. This study aimed to investigate candidate GBS vaccine targets, virulence factors, and antimicrobial resistance determinants. METHODS: We used whole-genome sequencing to characterize invasive GBS isolates from infants < 3 months of age obtained from a multicenter population-based study conducted from 2015 to 2021 in China. RESULTS: Overall, seven serotypes were detected from 278 GBS isolates, four (Ia, Ib, III, V) of which accounted for 97.8 %. We detected 30 sequence types (including 10 novel types) that were grouped into six clonal complexes (CCs: CC1, CC10, CC17, CC19, CC23 and CC651); three novel ST groups in CC17 were detected, and the rate of CC17, considered a hyperinvasive neonatal clone complex, was attached to 40.6 % (113/278). A total of 98.9 % (275/278) of isolates harbored at least one alpha-like protein gene. All GBS isolates contained at least one of three pilus backbone determinants and the pilus types PI-2b and PI-1 + PI-2a accounted for 79.8 % of the isolates. The 112 serotype III/CC17 GBS isolates were all positive for hvgA. Most of the isolates (75.2 %) were positive for serine-rich repeat glycoprotein determinants (srr1or srr2). Almost all isolates possessed cfb (99.6 %), c1IE (100 %), lmb (95.3 %) or pavA (100 %) gene. Seventy-seven percent of isolates harboured more than three antimicrobial resistance genes with 28.4 % (79/278) gyrA quinoloneresistancedeterminants mutation, 83.8 % (233/278) carrying tet cluster genes and 77.3 % (215/278) carrying erm genes which mediated fluoroquinolone, tetracycline and clindamycin resistance, respectively." CONCLUSIONS: The findings from this large whole-genome sequence of GBS isolates establish important baseline data required for further surveillance and evaluating the impact of future vaccine candidates.

Facilitating the development of urgently required combination vaccines.

The essence of a vaccine lies in its ability to elicit a set of immune responses specifically directed at a particular pathogen. Accordingly, vaccines were historically designed, developed, registered, recommended, procured, and administered as monopathogen formulations. Nonetheless, the control and elimination of an astonishing number of diseases was realised only after several once-separate vaccines were provided as combinations. Unfortunately, the current superabundance of recommended and pipeline vaccines is now at odds with the number of acceptable vaccine administrations and feasible health-care visits for vaccine recipients and health-care providers. Yet, few new combinations are in development because, in addition to the scientific and manufacturing hurdles intrinsic to coformulation, developers face a gauntlet of regulatory, policy, and commercialisation obstacles in a milieu still largely designed for monopathogen vaccines. We argue here that national policy makers and public health agencies should prospectively identify and advocate for the development of new multipathogen combination vaccines, and suggest ways to accelerate the regulatory pathways to licensure of combinations and other concrete, innovative steps to mitigate current obstacles.

Interlaboratory comparison of a multiplex immunoassay that measures human serum IgG antibodies against six-group B streptococcus polysaccharides.

Measurement of IgG antibodies against group B streptococcus (GBS) capsular polysaccharide (CPS) by use of a standardized and internationally accepted multiplex immunoassay is important for the evaluation of candidate maternal GBS vaccines in order to compare results across studies. A standardized assay is also required if serocorrelates of protection against invasive GBS disease are to be established in infant sera for the six predominant GBS serotypes since it would permit the comparison of results across the six serotypes. We undertook an interlaboratory study across five laboratories that used standardized assay reagents and protocols with a panel of 44 human sera to measure IgG antibodies against GBS CPS serotypes Ia, Ib, II, III, IV, and V. The within-laboratory intermediate precision, which included factors like the lot of coated beads, laboratory analyst, and day, was generally below 20% relative standard deviation (RSD) for all six serotypes, across all five laboratories. The cross-laboratory reproducibility was < 25% RSD for all six serotypes, which demonstrated the consistency of results across the different laboratories. Additionally, anti-CPS IgG concentrations for the 44-member human serum panel were established. The results of this study showed assay robustness and that the resultant anti-CPS IgG concentrations were reproducible across laboratories for the six GBS CPS serotypes when the standardized assay was used.

Comparable safety and non-inferior immunogenicity of the SARS-CoV-2 mRNA vaccine candidate PTX-COVID19-B and BNT162b2 in a phase 2 randomized, observer-blinded study.

In the aftermath of the COVID-19 pandemic, the evolution of the SARS-CoV-2 into a seasonal pathogen along with the emergence of new variants, underscores the need for dynamic and adaptable responses, emphasizing the importance of sustained vaccination strategies. This observer-blind, double-dummy, randomized immunobridging phase 2 study (NCT05175742) aimed to compare the immunogenicity induced by two doses of 40 µg PTX-COVID19-B vaccine candidate administered 28 days apart, with the response induced by two doses of 30 µg Pfizer-BioNTech COVID-19 vaccine (BNT162b2), administered 21 days apart, in Nucleocapsid-protein seronegative adults 18-64 years of age. Both vaccines were administrated via intramuscular injection in the deltoid muscle. Two weeks after the second dose, the neutralizing antibody (NAb) geometric mean titer ratio and seroconversion rate met the non-inferiority criteria, successfully achieving the primary immunogenicity endpoints of the study. PTX-COVID19-B demonstrated similar safety and tolerability profile to BNT162b2 vaccine. The lowest NAb response was observed in subjects with low-to-undetectable NAb at baseline or no reported breakthrough infection. Conversely, participants who experienced breakthrough infections during the study exhibited higher NAb titers. This study also shows induction of cell-mediated immune (CMI) responses by PTX-COVID19-B. In conclusion, the vaccine candidate PTX-COVID19-B demonstrated favourable safety profile along with immunogenicity similar to the active comparator BNT162b2 vaccine.

Vaccine value profile for Klebsiella pneumoniae.

Klebsiella pneumoniae causes community- and healthcare-associated infections in children and adults. Globally in 2019, an estimated 1.27 million (95% Uncertainty Interval [UI]: 0.91-1.71) and 4.95 million (95% UI: 3.62-6.57) deaths were attributed to and associated with bacterial antimicrobial resistance (AMR), respectively. K. pneumoniae was the second leading pathogen in deaths attributed to AMR resistant bacteria. Furthermore, the rise of antimicrobial resistance in both community- and hospital-acquired infections is a concern for neonates and infants who are at high risk for invasive bacterial disease. There is a limited antibiotic pipeline for new antibiotics to treat multidrug resistant infections, and vaccines targeted against K. pneumoniae are considered to be of priority by the World Health Organization. Vaccination of pregnant women against K. pneumoniae could reduce the risk of invasive K.pneumoniae disease in their young offspring. In addition, vulnerable children, adolescents and adult populations at risk of K. pneumoniae disease with underlying diseases such as immunosuppression from underlying hematologic malignancy, chemotherapy, patients undergoing abdominal and/or urinary surgical procedures, or prolonged intensive care management are also potential target groups for a K. pneumoniae vaccine. A 'Vaccine Value Profile' (VVP) for K.pneumoniae, which contemplates vaccination of pregnant women to protect their babies from birth through to at least three months of age and other high-risk populations, provides a high-level, holistic assessment of the available information to inform the potential public health, economic and societal value of a pipeline of K. pneumoniae vaccines and other preventatives and therapeutics. This VVP was developed by a working group of subject matter experts from academia, non-profit organizations, public-private partnerships, and multi-lateral organizations, and in collaboration with stakeholders from the WHO. All contributors have extensive expertise on various elements of the K.pneumoniae VVP and collectively aimed to identify current research and knowledge gaps. The VVP was developed using only existing and publicly available information.

Factors predicting mortality in hospitalised HIV-negative children with lower-chest-wall indrawing pneumonia and implications for management.

INTRODUCTION: In 2012, the World Health Organization revised treatment guidelines for childhood pneumonia with lower chest wall indrawing (LCWI) but no 'danger signs', to recommend home-based treatment. We analysed data from children hospitalized with LCWI pneumonia in the Pneumonia Etiology Research for Child Health (PERCH) study to identify sub-groups with high odds of mortality, who might continue to benefit from hospital management but may not be admitted by staff implementing the 2012 guidelines. We compare the proportion of deaths identified using the criteria in the 2012 guidelines, and the proportion of deaths identified using an alternative set of criteria from our model. METHODS: PERCH enrolled a cohort of 2189 HIV-negative children aged 2-59 months who were admitted to hospital with LCWI pneumonia (without obvious cyanosis, inability to feed, vomiting, convulsions, lethargy or head nodding) between 2011-2014 in Kenya, Zambia, South Africa, Mali, The Gambia, Bangladesh, and Thailand. We analysed risk factors for mortality among these cases using predictive logistic regression. Malnutrition was defined as mid-upper-arm circumference <125mm or weight-for-age z-score <-2. RESULTS: Among 2189 cases, 76 (3·6%) died. Mortality was associated with oxygen saturation <92% (aOR 3·33, 1·99-5·99), HIV negative but exposed status (4·59, 1·81-11·7), moderate or severe malnutrition (6·85, 3·22-14·6) and younger age (infants compared to children 12-59 months old, OR 2·03, 95%CI 1·05-3·93). At least one of three risk factors: hypoxaemia, HIV exposure, or malnutrition identified 807 children in this population, 40% of LCWI pneumonia cases and identified 86% of the children who died in hospital (65/76). Risk factors identified using the 2012 WHO treatment guidelines identified 66% of the children who died in hospital (n = 50/76). CONCLUSIONS: Although it focuses on treatment failure in hospital, this study supports the proposal for better risk stratification of children with LCWI pneumonia. Those who have hypoxaemia, any malnutrition or those who were born to HIV positive mothers, experience poorer outcomes than other children with LCWI pneumonia. Consistent identification of these risk factors should be prioritised and children with at least one of these risk factors should not be managed in the community.

Bacterial and Candida Colonization of Neonates in a Regional Hospital in South Africa.

BACKGROUND: Neonatal colonization with multidrug-resistant (MDR) Enterobacter spp., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterococcus faecium (ESKAPE) and Candida spp. often precedes invasive hospital-acquired infections. We investigated the prevalence and dynamics of neonatal ESKAPE and Candida spp. colonization from hospital admission until discharge (or death) and followed up for invasive disease. METHODS: Prospective longitudinal surveillance for neonatal ESKAPE and Candida spp. colonization was conducted over 6 months at a South African regional hospital. Neonates enrolled at birth had swabs (nasal, 2× skin and rectal) collected within 24 hours and every 48-96 hours thereafter, until discharge or death. ESKAPE and Candida spp. were cultured for and antimicrobial susceptibility was performed on bacterial isolates. Whole-genome sequencing was undertaken on paired samples with the same bacterial species from colonizing and invasive disease episodes in the same child. RESULTS: Of 102 enrolled neonates, 79% (n = 81) were colonized by ≥1 ESKAPE organism by time of discharge or death. Forty-four percent (36/81) were colonized within 24 hours of birth. Common colonizers were K. pneumoniae (70%; n = 57) and Enterobacter spp. (43%; n = 35). Almost all MDR organisms (93%) were Gram-negative. Forty-two (45%, 42/93) newborns acquired Candida spp. (skin only) colonization, commonly Candida parapsilosis (69%; n = 29). For 2 children with K. pneumoniae colonization and sepsis, the bloodstream and colonizing isolates were genetically different, whereas the single A. baumannii colonizing and blood isolate pair were genetically identical. CONCLUSIONS: We report a high prevalence of MDR ESKAPE and Candida spp. colonization in a regional neonatal unit. Interventions to reduce the high incidence of hospital-acquired neonatal infections should include reducing high colonization rates.

Gut Microbiota and Other Factors Associated With Increased Regulatory T Cells in Hiv-exposed Uninfected Infants.

HIV-exposed uninfected infants (HEU) have higher infectious morbidity than HIV-unexposed infants (HUU). HEU have multiple immune defects of unknown origin. We hypothesized that HEU have higher regulatory T cells (Treg) than HUU, which may dampen their immune defenses against pathogens. We compared 25 Treg subsets between HEU and HUU and sought the factors that may affect Treg frequencies. At birth, 3 Treg subsets, including CD4 + FOXP3 + and CD4 + FOXP3 + CD25+, had higher frequencies in 123 HEU than 117 HUU and 3 subsets were higher in HUU. At 28 and 62 weeks of life, 5 Treg subsets were higher in HEU, and none were higher in HUU. The frequencies of the discrepant Treg subsets correlated at birth with differential abundances of bacterial taxas in maternal gut microbiome and at subsequent visits in infant gut microbiomes. In vitro, bacterial taxa most abundant in HEU expanded Treg subsets with higher frequencies in HEU, recapitulating the in vivo observations. Other factors that correlated with increased Treg were low maternal CD4 + T cells in HEU at birth and male sex in HUU at 28 weeks. We conclude that maternal and infant gut dysbiosis are central to the Treg increase in HEU and may be targeted by mitigating interventions.

Post-mortem investigation of deaths due to pneumonia in children aged 1-59 months in sub-Saharan Africa and South Asia from 2016 to 2022: an observational study.

BACKGROUND: The Child Health and Mortality Prevention Surveillance (CHAMPS) Network programme undertakes post-mortem minimally invasive tissue sampling (MITS), together with collection of ante-mortem clinical information, to investigate causes of childhood deaths across multiple countries. We aimed to evaluate the overall contribution of pneumonia in the causal pathway to death and the causative pathogens of fatal pneumonia in children aged 1-59 months enrolled in the CHAMPS Network. METHODS: In this observational study we analysed deaths occurring between Dec 16, 2016, and Dec 31, 2022, in the CHAMPS Network across six countries in sub-Saharan Africa (Ethiopia, Kenya, Mali, Mozambique, Sierra Leone, and South Africa) and one in South Asia (Bangladesh). A standardised approach of MITS was undertaken on decedents within 24-72 h of death. Diagnostic tests included blood culture, multi-organism targeted nucleic acid amplifications tests (NAATs) of blood and lung tissue, and histopathology examination of various organ tissue samples. An interdisciplinary expert panel at each site reviewed case data to attribute the cause of death and pathogenesis thereof on the basis of WHO-recommended reporting standards. FINDINGS: Pneumonia was attributed in the causal pathway of death in 455 (40·6%) of 1120 decedents, with a median age at death of 9 (IQR 4-19) months. Causative pathogens were identified in 377 (82·9%) of 455 pneumonia deaths, and multiple pathogens were implicated in 218 (57·8%) of 377 deaths. 306 (67·3%) of 455 deaths occurred in the community or within 72 h of hospital admission (presumed to be community-acquired pneumonia), with the leading bacterial pathogens being Streptococcus pneumoniae (108 [35·3%]), Klebsiella pneumoniae (78 [25·5%]), and non-typeable Haemophilus influenzae (37 [12·1%]). 149 (32·7%) deaths occurred 72 h or more after hospital admission (presumed to be hospital-acquired pneumonia), with the most common pathogens being K pneumoniae (64 [43·0%]), Acinetobacter baumannii (19 [12·8%]), S pneumoniae (15 [10·1%]), and Pseudomonas aeruginosa (15 [10·1%]). Overall, viruses were implicated in 145 (31·9%) of 455 pneumonia-related deaths, including 54 (11·9%) of 455 attributed to cytomegalovirus and 29 (6·4%) of 455 attributed to respiratory syncytial virus. INTERPRETATION: Pneumonia contributed to 40·6% of all childhood deaths in this analysis. The use of post-mortem MITS enabled biological ascertainment of the cause of death in the majority (82·9%) of childhood deaths attributed to pneumonia, with more than one pathogen being commonly implicated in the same case. The prominent role of K pneumoniae, non-typable H influenzae, and S pneumoniae highlight the need to review empirical management guidelines for management of very severe pneumonia in low-income and middle-income settings, and the need for research into new or improved vaccines against these pathogens. FUNDING: Bill & Melinda Gates Foundation.

Burden of child mortality from malaria in high endemic areas: Results from the CHAMPS network using minimally invasive tissue sampling.

BACKGROUND: Malaria is a leading cause of childhood mortality worldwide. However, accurate estimates of malaria prevalence and causality among patients who die at the country level are lacking due to the limited specificity of diagnostic tools used to attribute etiologies. Accurate estimates are crucial for prioritizing interventions and resources aimed at reducing malaria-related mortality. METHODS: Seven Child Health and Mortality Prevention Surveillance (CHAMPS) Network sites collected comprehensive data on stillbirths and children <5 years, using minimally invasive tissue sampling (MITS). A DeCoDe (Determination of Cause of Death) panel employed standardized protocols for assigning underlying, intermediate, and immediate causes of death, integrating sociodemographic, clinical, laboratory (including extensive microbiology, histopathology, and malaria testing), and verbal autopsy data. Analyses were conducted to ascertain the strength of evidence for cause of death (CoD), describe factors associated with malaria-related deaths, estimate malaria-specific mortality, and assess the proportion of preventable deaths. FINDINGS: Between December 3, 2016, and December 31, 2022, 2673 deaths underwent MITS and had a CoD attributed from four CHAMPS sites with at least 1 malaria-attributed death. No malaria-attributable deaths were documented among 891 stillbirths or 924 neonatal deaths, therefore this analysis concentrates on the remaining 858 deaths among children aged 1-59 months. Malaria was in the causal chain for 42.9% (126/294) of deaths from Sierra Leone, 31.4% (96/306) in Kenya, 18.2% (36/198) in Mozambique, 6.7% (4/60) in Mali, and 0.3% (1/292) in South Africa. Compared to non-malaria related deaths, malaria-related deaths skewed towards older infants and children (p < 0.001), with 71.0% among ages 12-59 months. Malaria was the sole infecting pathogen in 184 (70.2%) of malaria-attributed deaths, whereas bacterial and viral co-infections were identified in the causal pathway in 24·0% and 12.2% of cases, respectively. Malnutrition was found at a similar level in the causal pathway of both malaria (26.7%) and non-malaria (30.7%, p = 0.256) deaths. Less than two-thirds (164/262; 62.6%) of malaria deaths had received antimalarials prior to death. Nearly all (98·9%) malaria-related deaths were deemed preventable. INTERPRETATION: Malaria remains a significant cause of childhood mortality in the CHAMPS malaria-endemic sites. The high bacterial co-infection prevalence among malaria deaths underscores the potential benefits of antibiotics for severe malaria patients. Compared to non-malaria deaths, many of malaria-attributed deaths are preventable through accessible malaria control measures.

SARS-CoV-2 Viral Replication Persists in the Human Lung for Several Weeks after Symptom Onset.

Rationale: In the upper respiratory tract, replicating (culturable) severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is recoverable for ∼4-8 days after symptom onset, but there is a paucity of data about the frequency and duration of replicating virus in the lower respiratory tract (i.e., the human lung).Objectives: We undertook lung tissue sampling (needle biopsy) shortly after death in 42 mechanically ventilated decedents during the Beta and Delta waves. An independent group of 18 ambulatory patients served as a control group.Methods: Lung biopsy cores from decedents underwent viral culture, histopathological analysis, electron microscopy, transcriptomic profiling, and immunohistochemistry.Measurements and Main Results: Thirty-eight percent (16 of 42) of mechanically ventilated decedents had culturable virus in the lung for a median of 15 days (persisting for up to 4 wk) after symptom onset. Lung viral culture positivity was not associated with comorbidities or steroid use. Delta but not Beta variant lung culture positivity was associated with accelerated death and secondary bacterial infection (P < 0.05). Nasopharyngeal culture was negative in 23.1% (6 of 26) of decedents despite lung culture positivity. This hitherto undescribed biophenotype of lung-specific persisting viral replication was associated with an enhanced transcriptomic pulmonary proinflammatory response but with concurrent viral culture positivity.Conclusions: Concurrent rather than sequential active viral replication continues to drive a heightened proinflammatory response in the human lung beyond the second week of illness and was associated with variant-specific increased mortality and morbidity. These findings have potential implications for the design of interventional strategies and clinical management of patients with severe coronavirus disease (COVID-19).

Infants Receiving a Single Dose of Nirsevimab to Prevent RSV Do Not Have Evidence of Enhanced Disease in Their Second RSV Season.

To characterize nirsevimab in the prevention of RSV, children from the Phase 3 MELODY trial were followed through their second RSV season. No increase in medically attended RSV lower respiratory tract infections or evidence of antibody-dependent enhancement of infection or disease severity was found for nirsevimab vs placebo recipients. Clinical Trial Registration: Clinicaltrials.gov, NCT03979313, https://clinicaltrials.gov/ct2/show/NCT03979313.

In-silico identification of potential inhibitors against FabI protein in Klebsiella pneumoniae.

The development of new antimicrobial drugs is needed to combat multi-drug resistant and novel hypervirulent strains of Klebsiella pneumoniae (KPN) that are associated with increased morbidity and mortality globally. The FabI protein plays a crucial role in fatty acid biosynthesis and has been identified as an important target for in-silico, in-vitro, and in-vivo drug discovery. In this study we have used computer integrated-drug discovery approaches and binding-free energy calculations to identify three novel inhibitors (21272541, 67724550, and 67724551) of the FabI protein. All inhibitors showed strong affinity including van der Waals energy, electrostatic energy, polar and non-polar energies; however, the 21272541 compound was the most effective inhibitor and bound with the strongest affinity (ΔGbind -59.02 kcal/mol) to the FabI protein. Nevertheless, all three inhibitors are promising targets for new novel antimicrobial drugs that could contribute to the management of antimicrobial resistant KPN infections based on various computational analysis. Additional in-vitro and in-vivo clinical studies will be needed to confirm drug effectiveness for the treatment of KPN infections.

Hepatic Vitamin A Concentrations and Association with Infectious Causes of Child Death.

OBJECTIVES: To assess postmortem vitamin A (VA) concentrations in children under 5 years of age and evaluate the association between VA deficiency (VAD) and infectious causes of death (CoD). STUDY DESIGN: In this cross-sectional study from the Child Health and Mortality Prevention Surveillance (CHAMPS) Network, liver biopsies collected within 72 hours of death were analyzed from 405 stillbirths and children under 5 years in Kenya and South Africa. Total liver VA (TLVA) concentrations were quantified using ultra-performance liquid chromatography, and cutoffs of ≤0.1 µmol/g, >0.1 to <0.7 µmol/g, ≥0.7 to <1.0 µmol/g, and ≥1.0 µmol/g were used to define VAD, adequate VA status, high VA, and hypervitaminosis A, respectively. CoD were determined by expert panel review. RESULTS: Among 366 liver samples with viable extraction, pooled prevalences of VAD, adequacy, high VA, and hypervitaminosis were 34.2%, 51.1%, 6.0%, and 8.7%, respectively. VAD was more common among neonates compared with stillbirths, infants, or children, and among those with low birthweight (LBW), underweight, or stunting (P < .05). When adjusting for site, age, and sex, there was no significant association of VAD with increased infectious CoD (OR 1.9, 95% confidence interval [CI] 0.9, 3.8, P = .073). In stratified analyses, VA deficient boys, but not girls, had an increased risk of infectious CoD (OR 3.4, 95% CI 1.3, 10.3, P = .013). CONCLUSIONS: Definitive postmortem assessment of VA status identified both VAD and VA excess among children under 5 years of age in Kenya and South Africa. VAD in boys was associated with increased risk of infectious mortality. Our findings may inform a transition from universal VA supplementation (VAS) to targeted strategies in certain countries.