Determinants of lung function development from birth to age 5 years: an interrupted time series analysis of a South African birth cohort.

BACKGROUND: Early life is a key period that determines long-term health. Lung development in childhood predicts lung function attained in adulthood and morbidity and mortality across the life course. We aimed to assess the effect of early-life lower respiratory tract infection (LRTI) and associated risk factors on lung development from birth to school age in a South African birth cohort. METHODS: We prospectively followed children enrolled in a population-based cohort from birth (between March 5, 2012 and March 31, 2015) to age 5 years with annual lung function assessment. Data on multiple early-life exposures, including LRTI, were collected. The effect of early-life risk factors on lung function development from birth to age 5 years was assessed using the Generalised Additive Models for Location, Scale and Shape and Interrupted Time Series approach. FINDINGS: 966 children (475 [49·2%] female, 491 [50·8%] male) had lung function measured with oscillometry, tidal flow volume loops, and multiple breath washout. LRTI occurred in 484 (50·1%) children, with a median of 2·0 LRTI episodes (IQR 1·0-3·0) per child. LRTI was independently associated with altered lung function, as evidenced by lower compliance (0·959 [95% CI 0·941-0·978]), higher resistance (1·028 [1·016-1·041]), and higher respiratory rate (1·018 [1·063-1·029]) over 5 years. Additional impact on lung function parameters occurred with each subsequent LRTI. Respiratory syncytial virus (RSV) LRTI was associated with lower expiratory flow ratio (0·97 [0·95-0·99]) compared with non-RSV LRTI. Maternal factors including allergy, smoking, and HIV infection were also associated with altered lung development, as was preterm birth, low birthweight, female sex, and coming from a less wealthy household. INTERPRETATION: Public health interventions targeting LRTI prevention, with RSV a priority, are vital, particularly in low-income and middle-income settings. FUNDING: UK Medical Research Council Grant, The Wellcome Trust, The Bill & Melinda Gates Foundation, US National Institutes of Health Human Heredity and Health in Africa, South African Medical Research Council, Hungarian Scientific Research Fund, and European Respiratory Society.

Succession and determinants of the early life nasopharyngeal microbiota in a South African birth cohort.

BACKGROUND: Bacteria colonizing the nasopharynx play a key role as gatekeepers of respiratory health. Yet, dynamics of early life nasopharyngeal (NP) bacterial profiles remain understudied in low- and middle-income countries (LMICs), where children have a high prevalence of risk factors for lower respiratory tract infection. We investigated longitudinal changes in NP bacterial profiles, and associated exposures, among healthy infants from low-income households in South Africa. METHODS: We used short fragment (V4 region) 16S rRNA gene amplicon sequencing to characterize NP bacterial profiles from 103 infants in a South African birth cohort, at monthly intervals from birth through the first 12 months of life and six monthly thereafter until 30 months. RESULTS: Corynebacterium and Staphylococcus were dominant colonizers at 1 month of life; however, these were rapidly replaced by Moraxella- or Haemophilus-dominated profiles by 4 months. This succession was almost universal and largely independent of a broad range of exposures. Warm weather (summer), lower gestational age, maternal smoking, no day-care attendance, antibiotic exposure, or low height-for-age z score at 12 months were associated with higher alpha and beta diversity. Summer was also associated with higher relative abundances of Staphylococcus, Streptococcus, Neisseria, or anaerobic gram-negative bacteria, whilst spring and winter were associated with higher relative abundances of Haemophilus or Corynebacterium, respectively. Maternal smoking was associated with higher relative abundances of Porphyromonas. Antibiotic therapy (or isoniazid prophylaxis for tuberculosis) was associated with higher relative abundance of anerobic taxa (Porphyromonas, Fusobacterium, and Prevotella) and with lower relative abundances of health associated-taxa Corynebacterium and Dolosigranulum. HIV-exposure was associated with higher relative abundances of Klebsiella or Veillonella and lower relative abundances of an unclassified genus within the family Lachnospiraceae. CONCLUSIONS: In this intensively sampled cohort, there was rapid and predictable replacement of early profiles dominated by health-associated Corynebacterium and Dolosigranulum with those dominated by Moraxella and Haemophilus, independent of exposures. Season and antibiotic exposure were key determinants of NP bacterial profiles. Understudied but highly prevalent exposures prevalent in LMICs, including maternal smoking and HIV-exposure, were associated with NP bacterial profiles. Video Abstract.

Early childhood wheezing phenotypes and determinants in a South African birth cohort: longitudinal analysis of the Drakenstein Child Health Study.

BACKGROUND: Developmental trajectories of childhood wheezing in low-income and middle-income countries (LMICs) have not been well described. We aimed to derive longitudinal wheeze phenotypes from birth to 5 years in a South African birth cohort and compare those with phenotypes derived from a UK cohort. METHODS: We used data from the Drakenstein Child Health Study (DCHS), a longitudinal birth cohort study in a peri-urban area outside Cape Town, South Africa. Pregnant women (aged ≥18 years) were enrolled during their second trimester at two public health clinics. We followed up children from birth to 5 years to derive six multidimensional indicators of wheezing (including duration, temporal sequencing, persistence, and recurrence) and applied Partition Around Medoids clustering to derive wheeze phenotypes. We compared phenotypes with a UK cohort (the Avon Longitudinal Study of Parents and Children [ALSPAC]). We investigated associations of phenotypes with early-life exposures, including all-cause lower respiratory tract infection (LRTI) and virus-specific LRTI (respiratory syncytial virus, rhinovirus, adenovirus, influenza, and parainfluenza virus) up to age 5 years. We investigated the association of phenotypes with lung function at 6 weeks and 5 years. FINDINGS: Between March 5, 2012, and March 31, 2015, we enrolled 1137 mothers and there were 1143 livebirths. Four wheeze phenotypes were identified among 950 children with complete data: never (480 children [50%]), early transient (215 children [23%]), late onset (104 children [11%]), and recurrent (151 children [16%]). Multivariate adjusted analysis indicated that LRTI and respiratory syncytial virus-LRTI, but not other respiratory viruses, were associated with increased risk of recurrent wheeze (odds ratio [OR] 2·79 [95% CI 2·05-3·81] for all LTRIs; OR 2·59 [1·30-5·15] for respiratory syncytial virus-LRTIs). Maternal smoking (1·88 [1·12-3·02]), higher socioeconomic status (2·46 [1·23-4·91]), intimate partner violence (2·01 [1·23-3·29]), and male sex (2·47 [1·50-4·04]) were also associated with recurrent wheeze. LRTI and respiratory syncytial virus-LRTI were also associated with early transient and late onset clusters. Wheezing illness architecture differed between DCHS and ALSPAC; children included in ALSPAC in the early transient cluster wheezed for a longer period before remission and late-onset wheezing started at an older age, and no persistent phenotype was identified in DCHS. At 5 years, airway resistance was higher in children with early or recurrent wheeze compared with children who had never wheezed. Airway resistance increased from 6 weeks to 5 years among children with recurrent wheeze. INTERPRETATION: Effective strategies to reduce maternal smoking and psychosocial stressors and new preventive interventions for respiratory syncytial virus are urgently needed to optimise child health in LMICs. FUNDING: UK Medical Research Council; The Bill & Melinda Gates Foundation; National Institutes of Health Human Heredity and Health in Africa; South African Medical Research Council; Wellcome Trust.

Cystic fibrosis in South Africa: spectrum of disease and determinants of outcome.

INTRODUCTION: Little is known about cystic fibrosis (CF) in low- to middle-income settings. This study aimed to describe the spectrum and outcomes of CF in South Africa (SA) from the recently established SA CF registry (SACFR). METHODS: Demographic, diagnosis and clinical data were extracted from the SACFR. Cross-sectional univariable and multivariable regression analysis of best forced expiratory volume in 1 s (FEV1; age≥6 years) and nutrition (all ages) in 2018 was conducted to investigate factors associated with severe lung disease (SLD; FEV1 ≤3.0 z-score) and undernutrition. RESULTS: By December 2018, ancestry of 447 individuals included in the SACFR was Caucasian (315; 70%), mixed (87; 19%) and black African (41; 9%). Median diagnosis age was 7.6 months (IQR 2.7-37.1). Genotype was p.Phe508del homozygous (220; 49%); p.Phe508del heterozygous (144; 32%) and neither p.Phe508del or unknown Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) variant in 83 (19%); the second most frequent CFTR variant was 3120+1G>A, common in black Africans. Median age of patients in 2018 was 14.7 years (IQR 7.4-24.4). SLD was independently associated with chronic methicillin-resistant Staphylococcus aureus (MRSA) (adjusted odds ratio( aOR) 16.75; 95% CI 1.74-161.50), undernutrition (aOR 5.20; 95% CI 2.23-12.13) and age (aOR 2.23 per 10 years; 95% CI 1.50-3.31). Undernutrition was associated in univariable analysis with low weight at diagnosis, non-Caucasian ancestry, chronic P. aeruginosa infection and lower socioeconomic status. CONCLUSION: Interventions targeting MRSA infection and nutrition are needed to improve CF outcomes in SA. Most people with CF in SA are eligible for highly effective CFTR modulator therapy.

Asthma in South African adolescents: a time trend and risk factor analysis over two decades.

BACKGROUND: South Africa has undergone major economic and health system changes, impacting the epidemiology of childhood asthma. This study aimed to investigate prevalence time trends of asthma in South African adolescents over two decades and to identify associated risk factors. METHODS: A cross-sectional survey was conducted in 2017, in a randomised sample of 13-14-year-old Cape Town adolescents, using the standardised Global Asthma Network written, video and environmental questionnaires. Using time-trend analysis, the prevalence and severity of asthma were compared with data from the 2002 ISAAC phase III study. Environmental and social risk factors were analysed. RESULTS: A total of 3979 adolescents were included. The prevalence of lifetime and current asthma were 34.5% and 21.3%, respectively, on the self-report written questionnaire, similar to 2002 results. The prevalence of severe asthma in the previous 12 months increased, measured by wheeze limiting speech (7.8% to 11.8%), four or more attacks of wheezing (5.0% to 5.8%) or woken by wheeze on one or more nights per week (5.0% to 6.9%). The video questionnaire revealed increases in lifetime (16.9% to 22.5%), current (11.2% to 18.7%) and severe asthma (12.1% to 14.8%). Multivariate analysis showed associations between current asthma and smoking, female sex, pet exposure and higher socioeconomic status. Severe asthma was associated with smoking, pet exposure, outdoor pollution exposure and informal housing; 33% of those with severe or current asthma had been diagnosed. CONCLUSION: The prevalence of asthma is high, with increasing rates of severe asthma in adolescents. Underdiagnosis is a major concern and reduction in exposure to environmental factors, particularly smoking, and improved socioeconomic development are needed.

The child ecosystem and childhood pulmonary tuberculosis: A South African perspective.

INTRODUCTION: This study investigates drivers of childhood pulmonary tuberculosis (PTB) using a childhood ecosystem approach in South Africa. An ecosystem approach toward identifying risk factors for PTB may identify targeted interventions. METHODS: Data were collected as part of a prospective cohort study of children presenting at a primary care facility or tertiary hospital with possible TB. Characterization of the childhood ecosystem included proximal, medial, and distal determinants. Proximal determinants included child characteristics that could impact PTB outcomes. Medial determinants included relational factors, such as caregiver health, which might impact interactions with the child. Distal determinants included macro-level determinants of disease, such as socioeconomic status and food insecurity. Children who started on TB treatment were followed for up to 6 months. Multivariate regression models tested independent associations between factors associated with PTB in children. RESULTS: Of 1202 children enrolled, 242 (20%) of children had confirmed PTB, 756 (63%) were started on TB treatment, and 444 (37%) had respiratory conditions other than TB. In univariate analyses, childhood malnutrition and caregiver smoking were associated with treated or confirmed PTB. In multivariate analyses, proximal factors, such as male gender and hospitalization, as well as low socioeconomic status as a distal factor, were associated with PTB. CONCLUSIONS: Interventions may need to target subgroups of children and families with elevated proximal, medial, and distal risk factors for PTB. Screening for risk factors, such as caregiver's health, may guide targeting. The provision of social protection programs to bolster economic security may be an important intervention for attenuating childhood exposure to risk factors.

Population Pharmacokinetic Properties of Sulfadoxine and Pyrimethamine: a Pooled Analysis To Inform Optimal Dosing in African Children with Uncomplicated Malaria.

Sulfadoxine-pyrimethamine with amodiaquine is recommended by the World Health Organization as seasonal malaria chemoprevention for children aged 3 to 59 months in the sub-Sahel regions of Africa. Suboptimal dosing in children may lead to treatment failure and increased resistance. Pooled individual patient data from four previously published trials on the pharmacokinetics of sulfadoxine and pyrimethamine in 415 pediatric and 386 adult patients were analyzed using nonlinear mixed-effects modeling to evaluate the current dosing regimen and, if needed, to propose an optimized dosing regimen for children under 5 years of age. The population pharmacokinetics of sulfadoxine and pyrimethamine were both best described by a one-compartment disposition model with first-order absorption and elimination. Body weight, age, and nutritional status (measured as the weight-for-age Z-score) were found to be significant covariates. Allometric scaling with total body weight and the maturation of clearance in children by postgestational age improved the model fit. Underweight-for-age children were found to have 15.3% and 26.7% lower bioavailabilities of sulfadoxine and pyrimethamine, respectively, for each Z-score unit below -2. Under current dosing recommendations, simulation predicted that the median day 7 concentration was below the 25th percentile for a typical adult patient (50 kg) for sulfadoxine for patients in the weight bands of 8 to 9, 19 to 24, 46 to 49, and 74 to 79 kg and for pyrimethamine for patients in the weight bands of 8 to 9, 14 to 24, and 42 to 49 kg. An evidence-based dosing regimen was constructed that would achieve sulfadoxine and pyrimethamine exposures in young children and underweight-for-age young children that were similar to those currently seen in a typical adult.

Effect of Hazardous Alcohol Use During Pregnancy on Growth Outcomes at Birth: Findings from a South African Cohort Study.

BACKGROUND: Cohort studies have noted associations between hazardous alcohol use during pregnancy and infant growth outcomes, but many have not controlled for potential psychosocial confounders. To assess the unique contribution of hazardous alcohol use, we examined its effect on infant growth outcomes while controlling for maternal psychosocial stressors and hazardous tobacco and drug use in a cohort of 986 pregnant South African women enrolled into the Drakenstein Child Health Study between 2012 and 2015. METHODS: Data on psychosocial stressors and maternal risk behaviors were collected between 28 and 32 weeks of gestation. Participants were categorized as hazardous alcohol users if they obtained moderate or high scores (>10) on the Alcohol, Smoking and Substance Involvement Screening Test at this assessment or retrospectively reported drinking at least 2 drinks weekly during any trimester of pregnancy. Infant growth outcomes were recorded at delivery. Multivariable regression models examined correlates of hazardous alcohol use and associations between hazardous alcohol use and birth outcomes. RESULTS: Overall, 13% of mothers reported hazardous alcohol use. Recent exposure to intimate partner violence (adjusted odds ratio (aOR) = 2.08; 95% confidence interval (CI): 1.37, 3.18) and hazardous tobacco use (aOR = 5.03; 95% CI: 2.97, 8.52) were significant correlates of hazardous alcohol use. After controlling for potential psychosocial confounders, hazardous alcohol use remained associated with lower infant weight-for-age (B = -0.35, 95% CI: -0.56, -0.14), height-for-age (B = -0.46, 95% CI: -0.76, -0.17), and head-circumference-for-age z-scores (B = -0.43, 95% CI: -0.69, -0.17). CONCLUSIONS: Interventions to reduce hazardous alcohol use among pregnant women in South Africa are needed to prevent alcohol-related infant growth restrictions. As these growth deficits may lead to neurodevelopmental consequences, it is critical to identify alcohol-related growth restrictions at birth and link exposed infants to early interventions for neurodevelopment.

Early-life exposure to indoor air pollution or tobacco smoke and lower respiratory tract illness and wheezing in African infants: a longitudinal birth cohort study.

BACKGROUND: Indoor air pollution (IAP) and environmental tobacco smoke (ETS) are associated with lower respiratory tract illness (LRTI) or wheezing in children. However, the effect of the timing of these exposures, specifically antenatal versus postnatal, and of alternate fuel sources such as the increasingly used volatile organic compounds have not been well studied. We longitudinally investigated the effect of antenatal or postnatal IAP and ETS on LRTI or wheezing prevalence and severity in African infants. METHODS: Mother and infant pairs enrolled over a 3-year period in a birth cohort study in two centres in Paarl, South Africa, were followed for the first year of life for LRTI or wheezing illness. We measured exposure to IAP (particulate matter, nitrogen dioxide, sulphur dioxide, carbon monoxide, and volatile organic compounds benzene and toluene) using devices placed in homes, antenatally and postnatally. We measured ETS longitudinally by maternal self-report and by urine cotinine measures. Study staff trained in recognition of LRTI or wheeze documented all episodes, which were categorised according to WHO case definition criteria. We used multivariate logistic and Poisson regressions to explore associations. FINDINGS: Between March 1, 2012, and March 31, 2015, we enrolled 1137 mothers with 1143 livebirths. Of 1065 infants who attended at least one study visit, 524 episodes of LRTI occurred after discharge with a wheezing prevalence of 0·23 (95% CI 0·21-0·26) episodes per child year. Exposures associated with LRTI were antenatal maternal smoking (incidence rate ratio 1·62, 95% CI 1·14-2·30; p=0·004) or particulate matter (1·43, 1·06-1·95; p=0·008). Subanalyses of LRTI requiring hospitalisation (n=137) and supplemental oxygen (n=69) found antenatal toluene significantly increased the risk of LRTI-associated hospitalisation (odds ratio 5·13, 95% CI 1·43-18·36; p=0·012) and need for supplemental oxygen (13·21, 1·96-89·16; p=0·008). Wheezing illness was associated with both antenatal (incidence rate ratio 2·09, 95% CI 1·54-2·84; p<0·0001) and postnatal (1·27, 95% CI 1·03-1·56; p=0·024) maternal smoking. Antenatally, wheezing was associated with maternal passive smoke exposure (1·70, 1·25-2·31; p=0·001) and, postnatally, with any household member smoking (1·55, 1·17 -2·06; p=0·002). INTERPRETATION: Antenatal exposures were the predominant risk factors associated with LRTI or wheezing illness. Toluene was a novel exposure associated with severe LRTI. Urgent and effective interventions focusing on antenatal environmental factors are required, including smoking cessation programmes targeting women of childbearing age pre-conception and pregnant women. FUNDING: Bill & Melinda Gates Foundation, Discovery Foundation, South African Thoracic Society AstraZeneca Respiratory Fellowship, Medical Research Council South Africa, National Research Foundation South Africa, and CIDRI Clinical Fellowship.

Diagnostic Accuracy of the Xpert MTB/RIF Assay for Extrapulmonary Tuberculosis in Children With Musculoskeletal Infections.

BACKGROUND: Xpert MTB/RIF (Xpert) is useful for the diagnosis of extrapulmonary tuberculosis (TB) in adults, but there is limited evidence on its usefulness in children. We aimed to investigate the accuracy of Xpert for the diagnosis of extrapulmonary TB in children with musculoskeletal infections. METHODS: The diagnostic accuracy of Xpert was compared with a reference standard of culture or histopathology in children hospitalized with suspected osteoarticular TB in Cape Town, South Africa from June 2013 to May 2015. RESULTS: One hundred and nine samples of 102 patients (60 male; 58.8%) with a median age of 5.6 years (interquartile range: 2.2-8.7) were included. There were 23 samples with confirmed TB by culture or histology (21.1%); histology was positive in all of these, while culture was positive in 14 samples (12.8%). Xpert was positive in 17 samples (15.6%), providing a sensitivity of 73.9% (95% confidence interval: 51.6-89.8) and specificity of 100% (95% confidence interval: 95.7-100). Xpert was positive at a mean of 0.8 days (0.46-1.4) compared with 21 days (19-30) for culture, P < 0.001. Multidrug-resistant TB was detected on culture in a single sample that was negative on Xpert testing. CONCLUSIONS: Xpert confirmed extrapulmonary TB of bone and joints more accurately and faster than culture and should be used as a first-line test. Histology remains a useful test for musculoskeletal TB in children.

Structured approaches for the screening and diagnosis of childhood tuberculosis in a high prevalence region of South Africa.

OBJECTIVE: To measure agreement between nine structured approaches for diagnosing childhood tuberculosis; to quantify differences in the number of tuberculosis cases diagnosed with the different approaches, and to determine the distribution of cases in different categories of diagnostic certainty. METHODS: We investigated 1445 children aged < 2 years during a vaccine trial (2001-2006) in a rural South African community. Clinical, radiological and microbiological data were collected prospectively. Tuberculosis case status was determined using each of the nine diagnostic approaches. We calculated differences in case frequency and categorical agreement for binary (tuberculosis/not tuberculosis) outcomes using McNemar's test (with 95% confidence intervals, CIs) and Cohen's kappa coefficient (Kappa). FINDINGS: Tuberculosis case frequency ranged from 6.9% to 89.2% (median: 41.7). Significant differences in case frequency (P < 0.05) occurred in 34 of the 36 pair-wise comparisons between structured diagnostic approaches (range of absolute differences: 1.5-82.3%). Kappa ranged from 0.02 to 0.71 (median: 0.18). The two systems that yielded the highest case frequencies (89.2% and 70.0%) showed fair agreement (Kappa: 0.33); the two that yielded the lowest case frequencies (6.9% and 10.0%) showed slight agreement (Kappa: 0.18). CONCLUSION: There is only slight agreement between structured approaches for the screening and diagnosis of childhood tuberculosis and high variability between them in terms of case yield. Diagnostic systems that yield similarly low case frequencies may be identifying different subpopulations of children. The study findings do not support the routine clinical use of structured approaches for the definitive diagnosis of childhood tuberculosis, although high-yielding systems may be useful screening tools.

Comparison of T-SPOT.TB assay and tuberculin skin test for the evaluation of young children at high risk for tuberculosis in a community setting.

OBJECTIVE: We wished to compare the sensitivity of an enzyme-linked immunospot assay (T-SPOT.TB; Oxford Immunotec, Oxford, United Kingdom) and the tuberculin skin test for the detection of tuberculosis infection in very young children being evaluated for active tuberculosis in a rural community setting. METHODS: Children with a history of exposure to tuberculosis and children presenting to a local clinic or hospital with symptoms suggesting tuberculosis were admitted to a dedicated case verification ward. T-SPOT.TB testing was performed, and children were evaluated with a clinical examination, a tuberculin skin test, chest radiographs, and cultures of induced sputum and gastric lavage specimens. The diagnosis was determined by using a clinical algorithm. RESULTS: A total of 243 children (median age: 18 months) were recruited, of whom 214 (88%) had interpretable T-SPOT.TB results. Children > or =12 months of age were more likely than younger children to have positive T-SPOT.TB results, whereas tuberculin skin test results were unaffected by age. The sensitivity of the T-SPOT.TB was no better than that of the tuberculin skin test for culture-confirmed tuberculosis (50% and 80%, respectively) and was poorer for the combined group of culture-confirmed and clinically probable tuberculosis (40% and 52%, respectively). For the 50 children clinically categorized as not having tuberculosis, the specificity of both the T-SPOT.TB and the tuberculin skin test was 84%. CONCLUSIONS: For young children presenting in a community setting after exposure to tuberculosis or with symptoms suggesting tuberculosis, T-SPOT.TB cannot be used to exclude active disease. The sensitivity of this assay may be impaired for very young children.

Role of human metapneumovirus, human coronavirus NL63 and human bocavirus in infants and young children with acute wheezing.

The role of the novel respiratory viruses, human metapneumovirus (hMPV), human coronavirus NL63 (HCoV NL63) and human bocavirus (HBoV), in wheezing illness in children has not been well studied, especially in Africa. The aim of this study was to investigate the prevalence of hMPV, HCoV NL63 and HBoV in South African children with acute wheezing. A prospective study of consecutive children presenting with acute wheezing to a pediatric hospital from May 2004 to November 2005 was undertaken. A nasal swab was taken for reverse transcription-polymerase chain reaction (RT-PCR) and PCR for hMPV, HCoV NL63 and HBoV; when positive, the genes were sequenced. Shell vial culture for RSV, influenza A and B viruses, adenovirus and parainfluenza viruses 1, 2, 3 was performed on every 5th sample. Two hundred and forty two nasal swabs were collected from 238 children (median age 12.4 months). A novel respiratory virus was found in 44/242 (18.2%). hMPV, HBoV, and HCoV NL63 was found in 20 (8.3%), 18 (7.4%), and 6 (2.4%) of samples, respectively. Fifteen of 59 (25%) samples were positive for other respiratory viruses. Viral co-infections, occurred in 6/242 (2.5%). Phylogenetic analysis showed co-circulation of hMPV and HCoV NL63 A and B lineages, although only HBoV genotype st2 was found. Viruses are an important cause of wheezing in preschool children; hMPV, HCoV NL63, and HBoV are less common than the usual respiratory pathogens.