Burden, Etiology, and Risk Factors of Respiratory Virus Infections Among Symptomatic Preterm Infants in the Tropics: A Retrospective Single-Center Cohort Study

The epidemiology of critical respiratory diseases in ex-premature infants in Vietnam: A prospective single-center study

INTRODUCTION

This study aimed to describe the epidemiology and etiologies of critical respiratory diseases of ex-premature infants (EPIs) admitted to the Pediatric Intensive Care unit (PICU).

METHODS

Infants ≤2 years old with acute respiratory illnesses admitted to PICU of Vietnam National Children's Hospital from November 2019 to April 2021 were enrolled and followed up to hospital discharge. We compared respiratory pathogens, outcomes, and PICU resources utilized between EPIs and term infants. Among EPIs, we described clinical characteristics and evaluated the association between associated factors and mortality.

RESULTS

Among 1183 patients, aged ≤2 years were admitted for critical respiratory illnesses, 202 (17.1%) were EPIs. Respiratory viruses were detected in 53.5% and 38.2% among EPIs and term infants, respectively. Compared to term infants, a higher proportion of EPIs required mechanical ventilation (MV) (85.6 vs. 66.5%, p < .005) and vasopressor support (37.6 vs. 10.7%%, p < .005). EPIs had a higher median PICU length of stay (11.0 [IQR: 7; 22] vs. 6.0 days [IQR: 3; 11], p = .09), hospital length of stay (21.5 [IQR: 13; 40] vs. 10.0 days [IQR: 5; 18], p < .005) and case fatality rate (31.3% vs. 22.6%) compared to term infants. Among EPIs, PIM-3 score (adjusted odds ratio [aOR]: 1.51; 95% confidence interval [CI]: 1.30-1.75) and PELOD-2 score at admission (aOR: 1.41; 95% CI: 1.08-1.85) were associated with mortality.

CONCLUSIONS

EPIs with critical respiratory illnesses constituted a significant population in the PICU, required more PICU support, and had worse clinical outcomes compared to term infants.

Perinatal bacterial colonization and neonatal early-onset sepsis: A case-control study

BACKGROUND

The utility of determining maternal-neonatal surface colonization as detected by standard microbiological cultures around the time of birth is unclear. The aim of this study is to evaluate the association between maternal and neonatal surface colonization at birth and neonatal early onset sepsis (EOS).

OBJECTIVE

To investigate the association of white matter hyperintensities (WMHs) present in the brain with AD CSF biomarker levels.

METHODS

We conducted a case-control study of newborns admitted to the neonatal department of a referral women's and children's hospital from 2009 to 2017. Cases were infants with blood-culture-confirmed EOS (<3 days of life), and controls were infants without EOS randomly chosen based on the cases' date of birth. Maternal genitourinary and neonatal ear swab cultures were used to determine bacterial surface colonization status.

RESULTS

Fifty-one infants were diagnosed with EOS during the study period, where Escherichia coli (45%), and Group B Streptococcus (23%) accounted for 68% of infecting organisms. Compared to infants without EOS, those infected were more likely to have surface colonization of the mothers (60% vs 40%, p = 0.048) and infants (90% vs 11%, p < 0.001). In univariate analysis, chorioamnionitis [7.1 (95% CI 2.9, 16.8)], small-for-gestational-age [OR 0.08 (95% CI 0.02, 0.4)], exposure to antibiotics around time of birth [2.3 (95% CI 1.0, 5.1)], maternal surface colonization [2.2 (95% CI 1.0, 4.9)] and neonatal surface colonization [23.5 (95% CI 7.3, 76.1)] were significantly associated with EOS. Adjusting for potential confounders, neonatal colonization remained significantly associated with neonatal EOS [AOR 15.0 (95% CI 3.5, 64.2), p < 0.001].

CONCLUSION

In our setting with predominant Gram-negative EOS, neonatal colonization but not maternal colonization was significantly associated with EOS in the newborn.

Influences of environmental exposures on preterm lung disease

Introduction: Environmental factors play a critical role in the progression or resolution of chronic respiratory diseases. However, studies are limited on the impact of environmental risk factors on individuals born prematurely with lung disease after they leave the neonatal intensive care unit and are discharged into the home environment.Areas covered: In this review, we cover current knowledge of environmental exposures that impact outcomes of preterm respiratory disease, including air pollution, infections, and disparities. The limited data do suggest that certain exposures should be avoided and there are potential preventative strategies for other exposures. There is a need for additional research outside the neonatal intensive care unit that focuses on individual and community-level factors that affect long-term outcomes.Expert opinion: Preterm respiratory disease can impose a significant burden on infants, children, and young adults born prematurely, but may improve for many individuals over time. In this review, we outline the exposures that may potentially hasten, delay, or prevent resolution of lung injury in preterm children.

Influenza hospitalizations during childhood in children born preterm

Objective

The objective is to determine if children born preterm were at increased risk of influenza hospitalization up to age five.

Methods

National registry data on all children born in Norway between 2008 and 2011 were used in Cox regression models to estimate adjusted hazard ratios (aHRs) for influenza hospitalizations up to age five in children born preterm (<37 pregnancy weeks). HRs were also estimated separately for very preterm (<32 weeks), early term (37–38 weeks), and post‐term (≥42 weeks) children.

Results

Among 238,628 children born in Norway from January 2008 to December 2011, 15,086 (6.3%) were born preterm. There were 754 (0.3%) children hospitalized with influenza before age five. The rate of hospitalizations in children born preterm was 13.8 per 10,000 person‐years (95% confidence interval [CI] [11.3, 16.7]), and 5.9 per 10,000 person‐years (95% CI [5.5, 6.4]) in children born at term (≥37 weeks). Children born preterm had a higher risk of influenza hospitalization before age 5: aHR 2.33 (95% CI [1.85, 2.93]). The risk increased with decreasing gestational age and was highest among those born extremely/very preterm; aHR 4.07 (95% CI [2.63, 6.31]). Compared with children born at 40–41 weeks, children born early term also had an elevated risk of influenza hospitalization; aHR (37 weeks) 1.89 (95% CI [1.43, 2.50]), aHR (38 weeks) 1.43 (95% CI [1.15, 1.78]).

Conclusion

Children born preterm had a higher risk of influenza hospitalizations before age five. An elevated risk was also present among children born at an early term. Children born preterm could benefit from influenza vaccinations.

Review: The Nose as a Route for Therapy. Part 2 Immunotherapy

The nose provides a route of access to the body for inhalants and fluids. Unsurprisingly it has a strong immune defense system, with involvement of innate (e.g., epithelial barrier, muco- ciliary clearance, nasal secretions with interferons, lysozyme, nitric oxide) and acquired (e.g., secreted immunoglobulins, lymphocytes) arms. The lattice network of dendritic cells surrounding the nostrils allows rapid uptake and sampling of molecules able to negotiate the epithelial barrier. Despite this many respiratory infections, including SARS-CoV2, are initiated through nasal mucosal contact, and the nasal mucosa is a significant "reservoir" for microbes including Streptococcus pneumoniae, Neisseria meningitidis and SARS -CoV-2. This review includes consideration of the augmentation of immune defense by the nasal application of interferons, then the reduction of unnecessary inflammation and infection by alteration of the nasal microbiome. The nasal mucosa and associated lymphoid tissue (nasopharynx-associated lymphoid tissue, NALT) provides an important site for vaccine delivery, with cold-adapted live influenza strains (LAIV), which replicate intranasally, resulting in an immune response without significant clinical symptoms, being the most successful thus far. Finally, the clever intranasal application of antibodies bispecific for allergens and Intercellular Adhesion Molecule 1 (ICAM-1) as a topical treatment for allergic and RV-induced rhinitis is explained.

Universal Face Masking Reduces Respiratory Viral Infections Among Inpatient Very-Low-Birthweight Neonatal Infants

We reviewed the impact of a universal face masking policy on respiratory viral infections (RVIs) among admitted very-low-birthweight infants in our neonatal department. There was a significant decrease in RVI incidence, specifically in our step-down level 2 unit, with respiratory syncytial virus and parainfluenza virus being the most common viruses isolated.

Respiratory viral infections in hospitalised paediatric patients in the tropics

AIM

Respiratory viruses are a huge disease burden globally. An understanding of the seasonal trends and the ability to predict peak periods of respiratory virus disease incidence is useful for clinical care.

METHODS

This is a retrospective analysis of paediatric hospitalizations of laboratory-confirmed viral respiratory tract infections in KK Women's and Children's Hospital, Singapore, from 1 January 2011 to 31 December 2016. Standard direct immunofluorescence was used to detect respiratory syncytial virus (RSV), influenza A and B viruses, parainfluenza 1, 2 and 3 viruses, metapneumovirus and adenovirus.

RESULTS

A total of 97 840 specimens were analysed with a positive detection rate of 23.8%. RSV made up the largest proportion (42% of the total positive results), predominating between May to September. Influenza A had two peaks, June to July and December to January. Type 3 was the most common parainfluenza virus and showed annually recurring peaks. In contrast, parainfluenza 1 and 2, metapneumovirus and adenovirus had a biennial pattern. The test of seasonality detected identifiable seasonality for RSV and parainfluenza 3 virus.

CONCLUSIONS

In conclusion, respiratory viruses have different and overlapping seasonality in tropical Singapore. Respiratory virus testing for patients admitted for acute respiratory infection is useful to target antiviral therapies and appropriate infection control practices.

Etiology of febrile respiratory infections in the general adult population in Singapore, 2007-2013

Pathogens that cause upper respiratory infections are numerous and specific preventive and therapeutic strategies are scarce. In order to ascertain the etiological agents resulting in upper respiratory tract infections (URTI) in adults in Singapore, nasal swab samples were collected from 2057 patients presenting with fever at primary healthcare clinics in Singapore from December 2007 to February 2013. Samples were tested using the Luminex NxTAG Respiratory Pathogen Panel that includes 22 respiratory pathogen targets. Patient-reported symptoms and vital signs were recorded and full blood and differential counts taken. Pathogens were detected in the following order of frequency: influenza viruses, rhino-/enteroviruses, coronaviruses, parainfluenza viruses, pneumoviruses, adenovirus, bocavirus and C. pneumoniae. Fifteen virus species were detected as part of coinfections, in which rhinoviruses were the most commonly observed pathogen. Our results suggest that influenza viruses are the main etiological agents, but multiple other respiratory viruses contribute to the total burden of URTI in adults in Singapore.

Effectiveness of Palivizumab Against Respiratory Syncytial Virus Hospitalization Among Preterm Infants in a Setting With Year-Round Circulation

BACKGROUND

The year-round respiratory syncytial virus (RSV) circulation in tropical regions leads to different transmission patterns and burden of disease among infants born very preterm.

METHODS

We conducted a retrospective cohort study to estimate the effectiveness of palivizumab in preventing RSV hospitalization at 6 and 12 months after discharge, among infants born at <32 weeks' gestation in our tropical setting.

RESULTS

A total of 109 infants (26.3%) received palivizumab at discharge, of 415 who were eligible. All patients received ≥4 doses, with 105 infants (96.3%) completing 5 doses. Within 1 year after discharge, there were 35 RSV-associated admissions (3 [2.8%] in the palivizumab vs 32 [10.5%] in the nonpalivizumab group; P = .02). After adjustment for confounders, the effectiveness of palivizumab against RSV hospitalization was estimated to be 90% (95% confidence interval, 10%-99%) up to 6 months after discharge. The median time to RSV hospitalization was shorter in the nonpalivizumab than in the palivizumab group (median [range], 155 [15-358] vs 287 [145-359] days, respectively; P = .11). Five infants (14.3%), all from the nonpalivizumab group, required admission to the intensive care unit.

CONCLUSIONS

In our setting with year-round RSV circulation, palivizumab prophylaxis was effective in reducing RSV hospitalization among high-risk preterm infants of <32 weeks' gestation within the initial 6 months after discharge.

Human Type I Interferon Antiviral Effects in Respiratory and Reemerging Viral Infections

Type I interferons (IFN-I) are a group of related proteins that help regulate the activity of the immune system and play a key role in host defense against viral infections. Upon infection, the IFN-I are rapidly secreted and induce a wide range of effects that not only act upon innate immune cells but also modulate the adaptive immune system. While IFN-I and many IFN stimulated genes are well-known for their protective antiviral role, recent studies have associated them with potential pathogenic functions. In this review, we summarize the current knowledge regarding the complex effects of human IFN-I responses in respiratory as well as reemerging flavivirus infections of public health significance and the molecular mechanisms by which viral proteins antagonize the establishment of an antiviral host defense. Antiviral effects and immune modulation of IFN-stimulated genes is discussed in resisting and controlling pathogens. Understanding the mechanisms of these processes will be crucial in determining how viral replication can be effectively controlled and in developing safe and effective vaccines and novel therapeutic strategies.