Systems biology is an approach to comprehensively study complex interactions within a biological system. Most published systems vaccinology studies have utilized whole blood or peripheral blood mononuclear cells (PBMC) to monitor the immune response after vaccination. Because human blood is comprised of multiple hematopoietic cell types, the potential for masking responses of under-represented cell populations is increased when analyzing whole blood or PBMC. To investigate the contribution of individual cell types to the immune response after vaccination, we established a rapid and efficient method to purify human T and B cells, natural killer (NK) cells, myeloid dendritic cells (mDC), monocytes, and neutrophils from fresh venous blood. Purified cells were fractionated and processed in a single day. RNA-Seq and quantitative shotgun proteomics were performed to determine expression profiles for each cell type prior to and after inactivated seasonal influenza vaccination. Our results show that transcriptomic and proteomic profiles generated from purified immune cells differ significantly from PBMC. Differential expression analysis for each immune cell type also shows unique transcriptomic and proteomic expression profiles as well as changing biological networks at early time points after vaccination. This cell type-specific information provides a more comprehensive approach to monitor vaccine responses.

BackgroundVaccine development for influenza A/H5N1 is an important public health priority, but H5N1 vaccines are less immunogenic than seasonal influenza vaccines. Adjuvant System 03 (AS03) markedly enhances immune responses to H5N1 vaccine antigens, but the underlying molecular mechanisms are incompletely understood.Objective and MethodsWe compared the safety (primary endpoint), immunogenicity (secondary), gene expression (tertiary) and cytokine responses (exploratory) between AS03-adjuvanted and unadjuvanted inactivated split-virus H5N1 influenza vaccines. In a double-blinded clinical trial, we randomized twenty adults aged 18–49 to receive two doses of either AS03-adjuvanted (n = 10) or unadjuvanted (n = 10) H5N1 vaccine 28 days apart. We used a systems biology approach to characterize and correlate changes in serum cytokines, antibody titers, and gene expression levels in six immune cell types at 1, 3, 7, and 28 days after the first vaccination.ResultsBoth vaccines were well-tolerated. Nine of 10 subjects in the adjuvanted group and 0/10 in the unadjuvanted group exhibited seroprotection (hemagglutination inhibition antibody titer > 1:40) at day 56. Within 24 hours of AS03-adjuvanted vaccination, increased serum levels of IL-6 and IP-10 were noted. Interferon signaling and antigen processing and presentation-related gene responses were induced in dendritic cells, monocytes, and neutrophils. Upregulation of MHC class II antigen presentation-related genes was seen in neutrophils. Three days after AS03-adjuvanted vaccine, upregulation of genes involved in cell cycle and division was detected in NK cells and correlated with serum levels of IP-10. Early upregulation of interferon signaling-related genes was also found to predict seroprotection 56 days after first vaccination.ConclusionsUsing this cell-based systems approach, novel mechanisms of action for AS03-adjuvanted pandemic influenza vaccination were observed.Trial RegistrationClinicalTrials.gov NCT01573312

Diarrheal disease, still a major cause of childhood illness, is caused by numerous, diverse infectious microorganisms, which are differentially sensitive to environmental conditions. Enteropathogen‐specific impacts of climate remain underexplored. Results from 15 studies that diagnosed enteropathogens in 64,788 stool samples from 20,760 children in 19 countries were combined. Infection status for 10 common enteropathogens—adenovirus, astrovirus, norovirus, rotavirus, sapovirus, Campylobacter , ETEC, Shigella , Cryptosporidium and Giardia —was matched by date with hydrometeorological variables from a global Earth observation dataset—precipitation and runoff volume, humidity, soil moisture, solar radiation, air pressure, temperature, and wind speed. Models were fitted for each pathogen, accounting for lags, nonlinearity, confounders, and threshold effects. Different variables showed complex, non‐linear associations with infection risk varying in magnitude and direction depending on pathogen species. Rotavirus infection decreased markedly following increasing 7‐day average temperatures—a relative risk of 0.76 (95% confidence interval: 0.69–0.85) above 28°C—while ETEC risk increased by almost half, 1.43 (1.36–1.50), in the 20–35°C range. Risk for all pathogens was highest following soil moistures in the upper range. Humidity was associated with increases in bacterial infections and decreases in most viral infections. Several virus species' risk increased following lower‐than‐average rainfall, while rotavirus and ETEC increased with heavier runoff. Temperature, soil moisture, and humidity are particularly influential parameters across all enteropathogens, likely impacting pathogen survival outside the host. Precipitation and runoff have divergent associations with different enteric viruses. These effects may engender shifts in the relative burden of diarrhea‐causing agents as the global climate changes.

We examined nasopharyngeal pneumococcal colonization density patterns surrounding acute respiratory illnesses (ARI) in young children in Peru. Pneumococcal densities were dynamic, gradually increasing leading up to an ARI, peaking during the ARI, and decreasing after the ARI. Rhinovirus co-infection was associated with higher pneumococcal densities.

Background Viruses are commonly detected in children with acute respiratory illnesses (ARI) and in asymptomatic children. Longitudinal studies of viral detections during asymptomatic periods surrounding ARI could facilitate interpretation of viral detections but are currently scant. Methods We used reverse transcription-polymerase chain reaction (RT-PCR) to analyze respiratory samples from young Andean children for viruses during asymptomatic periods within 8-120 days of index ARI (cough or fever). We compared viral detections over time within children and explored RT-PCR cycle thresholds (CT) as surrogates for viral loads. Results At least one respiratory virus was detected in 367 (43%) of 859 samples collected during asymptomatic periods, with more frequent detections in periods with rhinorrhea (49%) than those without (34%, p<0.001). Relative to index ARI with human rhinovirus (HRV), adenovirus (AdV), respiratory syncytial virus (RSV), and parainfluenza virus (PIV) detected, the same virus was also detected during 32%, 22%, 10%, and 3% of asymptomatic periods, respectively. RSV was only detected 8-30 days after index RSV ARI, whereas HRV and AdV were detected throughout asymptomatic periods. Human metapneumovirus (MPV) and influenza were rarely detected during asymptomatic periods (<3%). No significant differences were observed in the CT for HRV or AdV during asymptomatic periods relative to ARI. For RSV, CT were significantly lower during ARI relative to the asymptomatic period (p=0.03). Conclusions These findings indicate that influenza, MPV, PIV, and RSV detections in children with ARI usually indicate a causal relationship. When HRV or AdV is detected during ARI, the causal relationship is less certain.

Increased nasopharyngeal pneumococcal (Streptococcus pneumoniae) colonization density has been associated with invasive pneumococcal disease, but factors that increase pneumococcal density are poorly understood. We evaluated pneumococcal densities in nasopharyngeal samples from asymptomatic young children from Peru and their association with subsequent acute respiratory illness (ARI). Total pneumococcal densities (encompassing all present serotypes) during asymptomatic periods were significantly higher when a respiratory virus was detected versus when no virus was detected (p<0.001). In adjusted analyses, increased pneumococcal density was significantly associated with the risk for a subsequent ARI (p<0.001), whereas asymptomatic viral detection alone was associated with lower risk for subsequent ARI. These findings suggest that interactions between viruses and pneumococci in the nasopharynx during asymptomatic periods might have a role in onset of subsequent ARI. The mechanisms for these interactions, along with other potentially associated host and environmental factors, and their role in ARI pathogenesis and pneumococcal transmission require further elucidation.

The role of health literacy on HIV outcomes has not been evaluated widely in Africa, in part because few appropriate literacy measures exist. We developed a 16-item scale, the HIV Literacy Test (HIV-LT) to assess literacy-related tasks needed to participate in HIV care. Items were scored as correct or incorrect; higher scores indicated higher literacy skill (range 0–100 %). We tested internal reliability (Kuder–Richardson coefficient) of the HIV-LT in a convenience sample of 319 Portuguese-speaking, HIV infected adults on antiretroviral treatment in Maputo, Mozambique. Construct validity was assessed by a hypothetical model developed a priori. The HIV-LT was reliable and valid to measure participants’ literacy skills. The mean HIV-LT score was 42 %; literacy skills applicable to HIV care were challenging for many participants. The HIV-LT could be used to assess the relationship of literacy and HIV-related outcomes in diverse settings, and evaluate interventions to improve health communication for those in HIV care.Electronic supplementary materialThe online version of this article (doi:10.1007/s10461-016-1348-3) contains supplementary material, which is available to authorized users.

BACKGROUND Little is known about the epidemiology and outcomes of neurologic complications associated with COVID-19 in children. METHODS We performed a cross-sectional study of children 2 months to &lt;18 years with COVID-19 discharged from 52 children's hospitals from March 2020-March 2022. Neurologic complications were defined as encephalopathy, encephalitis, aseptic meningitis, febrile seizure, non-febrile seizure, brain abscess and bacterial meningitis, Reye’s syndrome, and cerebral infarction. We assessed length of stay (LOS), intensive care unit (ICU) admission, 30-day readmissions, deaths, and hospital costs. We used multivariable logistic regression to identify factors associated with neurologic complications. RESULTS Of 15,137 children hospitalized with COVID-19, 1060 (7.0%) had a concurrent diagnosis of a neurologic complication. The most frequent neurologic complications were febrile seizures (3.9%), non-febrile seizures (2.3%) and encephalopathy (2.2%). Hospital LOS, ICU admission, ICU LOS, 30-day readmissions, deaths, and hospital costs were higher in children with neurologic complications compared to those without complications. Factors associated with lower odds of neurologic complications included: younger age (aOR 0.97, 95% CI 0.96, 0.98), occurrence during Delta variant predominant time period (aOR 0.71, 95% CI 0.57, 0.87), presence of a non-neurologic complex chronic condition (CCC) (aOR 0.80, 95% CI 0.69, 0.94). Presence of a neurologic CCC was associated with a higher odds of neurologic complication (aOR 4.14, 95% CI 3.48, 4.92). CONCLUSIONS Neurologic complications are common in children hospitalized with COVID-19 and are associated with worse hospital outcomes. Our findings emphasize the importance of COVID-19 immunization in children, especially in high-risk populations, such as those with neurologic co-morbidity.