Several studies have examined post-bronchiolitis psychological outcomes in school-aged children. Martimbianco et al. (11) investigated the pulmonary and neurocognitive impact of severe bronchiolitis on children requiring mechanical ventilation. Their findings showed that survivors face intellectual and neurodevelopmental challenges later in life, including memory and attention deficits. Similarly, Freeman et al. (12) linked severe bronchiolitis to a higher risk of developing asthma and subsequent psychosocial stress. Contrarily, the findings of Wrotek et al. (13) showed no significant long-term psychological impact, such as depression and disruptive behavior, in most children hospitalized for bronchiolitis. This disparity between results could indicate variations in the severity of bronchiolitis, coping mechanisms, or socioeconomic and environmental factors across study populations.

Influenza may also lead to various long-term psychological effects among children. Research conducted on adolescents with physical health issues, such as those who were discharged from medical facilities following influenza infection, demonstrated the occurrence of psychological distress and reduced cognitive performance (2). Endo et al. (14) studied classroom transmission of influenza in Japanese primary schools, observing disruptions in learning and social interactions due to school absenteeism. Moreover, a prospective observational study by Hoy et al. (15) demonstrated that annual influenza vaccination effectively minimized the severity of flu-related symptoms without showing any significant positive effects on long-term cognitive or psychological outcomes in school-aged children. Collectively, the findings of these studies suggest that although physical health might be acutely affected by influenza, residual psychological impacts can be subtle and may depend on vaccination coverage, timely treatment, and baseline health status.

Literature underscores the importance of psychological interventions in children with respiratory conditions including bronchiolitis and influenza. Szakács et al. (9) described psychiatric comorbidities in children with post-H1N1 narcolepsy, emphasizing that early psychological support can forestall or mitigate further psychopathological developments. Similarly, Stevens and Kelsall-Knight (16) noted that children with asthma benefit from counseling, demonstrating reduced anxiety levels and improved quality of life. Not all studies, however, document robust integration of mental health services. Freeman et al. (12) highlighted that psychological symptoms are often neglected in children with severe respiratory infections, especially in developing countries. This underscores the importance of comprehensive care that acknowledges both physical and mental health components for pediatric patients.

A systematic review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The literature search was conducted using PubMed, EMBASE, and the Cochrane Library. Reference lists of relevant articles were also examined. The review included randomized controlled trials (RCTs) and cohort and longitudinal studies on school-aged children (5–12 years) with a documented history of bronchiolitis or influenza infection in early childhood. Only studies evaluating long-term psychological outcomes—including anxiety, depression, cognitive function, or behavioral changes—at least 6 months post-infection were included. The search covered articles published between 2014 and 2022, without language restriction. Case reports, editorials, opinion pieces, or studies lacking explicit psychological or mental health outcomes, studies with follow-up periods of <6 months, and non-randomized trials were excluded. The keywords and search strings are presented in Table 1; study inclusion and exclusion criteria are listed in Table 2.

All references were imported into EndNote (Clarivate Analytics) for deduplication. Two independent reviewers (PS and JC) screened the titles and abstracts using Rayyan, a web-based screening tool. Full texts of potentially relevant studies were retrieved and reviewed thoroughly. Discrepancies were resolved through discussion until a consensus was reached. The final set of included studies was confirmed by both authors.

For data extraction, all identified abstracts and article citations were first reviewed for inclusion in this systematic review. A standardized MS Excel spreadsheet was created to capture relevant data from each included article, such as study characteristics (author, year of publication, design, and location), population details (participant age, sample size, and inclusion/exclusion criteria), exposure details (severity and timing of bronchiolitis or influenza infection), psychological outcomes (anxiety, depression, cognitive function, and behavioral impacts), follow-up duration, and key findings related to long-term mental health. All extracted data were checked for consistency and accuracy by both authors. This was supplemented with a careful analysis of the full text of each article to optimize the identification of all necessary data. PS performed the initial data extraction, which was independently validated by JC for accuracy. Any disagreements were reconciled through discussion. A PRISMA flowchart was developed to depict the selection process of studies included or excluded and the number of articles screened and included, along with the reasons for exclusions at each stage.

We employed the Cochrane risk of bias tool for RCTs and the Newcastle–Ottawa scale for observational studies, evaluating domains such as selection, performance, detection, and attrition bias. Studies were categorized as having a low, moderate, or high risk of bias.

A total of 464 articles were retrieved from the initial database search. After removing duplicates and articles that did not meet the initial screening criteria, 310 articles remained. Of these, 160 were excluded for being published outside the 2014–2022 timeframe or for lacking relevance to the study objectives. The full texts of the remaining 150 articles were reviewed against the inclusion and exclusion criteria, yielding 40 articles selected for detailed evaluation. Finally, 10 articles met all the eligibility criteria and were included in the qualitative synthesis (Figure 1).

The Cochrane risk of bias tool was used to assess the risk of bias and the quality of studies (11). The analysis revealed considerable variation in bias risk, necessitating careful interpretation of results. Most studies demonstrated low to moderate selection bias due to the use of matched cohorts and rigorous recruitment methods aimed at reducing confounding variables (14, 17). However, some studies relied on hospital-based samples, introducing a higher risk of selection bias and limiting the generalizability of findings (4). The risk of performance and detection biases was low for most studies, reflecting standardized treatment protocols and objective assessments (Table 3). However, some studies (18) were categorized as having higher risks due to non-blinded machine learning evaluations. Furthermore, attrition bias remained a concern in several studies where dropout rates and participant retention strategies were inadequately described (2, 19). Overall, although most studies provide valuable information, the presence of potential biases raises questions about the general and specific implications of the findings, emphasizing the need for further research to replicate conclusions in diverse samples.

Anxiety is the main psychological outcome in children experiencing respiratory infections and those receiving care in the ICU (22). Sahoo and Ghosh (4) conducted a cross-sectional study on children with severe lower respiratory tract infections (LRTIs) in a tertiary care hospital in Eastern India. They found that 78.5% of children experienced delays in receiving medical attention. The delay was more pronounced in children of illiterate mothers compared to those of literate mothers. This delay acts as a stressor for both children and their caregivers due to the unpredictability of the child's condition or worsening of symptoms. Additionally, 67% of families belonged to the lowest socioeconomic strata, a factor that likely heightened anxiety due to financial constraints and inadequate access to healthcare (Table 4).

Furthermore, children with a history of respiratory infections, particularly those requiring intensive care may experience long-term effects that further contribute to anxiety. In a single-center cohort study, de Sonnaville et al. (20) examined children aged 6–12 years who had undergone invasive mechanical ventilation for bronchiolitis. Of the 74 children treated, 26% had adverse long-term pulmonary outcomes, including asthma in 19% of patients (Table 4). A family history of atopic diseases increased the risk of asthma by approximately 6.4-fold, while prolonged mechanical ventilation was associated with worsened pulmonary outcomes. These long-term health concerns heighten parental stress, particularly regarding their child’s future health, physical activity limitations, and academic performance (23).

Another factor that explains the anxiety of affected families is the interaction between respiratory disorders and neurocognitive outcomes. de Sonnaville et al. (18) found that children with bronchiolitis requiring admission to the pediatric intensive care unit showed lower intelligence quotient (IQ) and poorer neurodevelopment than their healthy peers. These children also demonstrated deficits in attention and processing speed (MA = 54, p = 0.03). Additionally, lower birth weight and socioeconomic disadvantage were associated with reduced cognitive function, intensifying parental concerns about their child's educational and social prospects. Further research is necessary to explore the correlation between respiratory health, the emotional state of children and caregivers, and long-term psychological effects on children.

Bronchiolitis, as a respiratory infection, has been associated with psychological consequences, including depression and anxiety (24). A study conducted by Uchida et al. (21) examined the impact of influenza vaccination on symptom severity in children diagnosed with influenza and explored the broader mental health effects of respiratory diseases. This study included data from 13,217 children from elementary schools, of whom, 2,548 had influenza, 1,122 were vaccinated, and 1,426 were not (Table 4). Although both groups exhibited similar symptom frequency and fever duration, vaccinated children had significantly lower hospitalization rates, suggesting that vaccination may mitigate the severity of influenza-related symptoms. The study also calls for addressing both the physical and psychological health implications of respiratory infections.

Moreover, Benjamin-Chung et al. (17) discussed the effectiveness of a school-based influenza vaccination program in Oakland, California, assessing vaccination uptake, school absenteeism, and laboratory-confirmed influenza cases. Approximately, 7,502–10,006 (22%–28%) students were vaccinated annually. During the two subsequent influenza seasons 2016–2017 and 2017–2018, the intervention school group demonstrated increased vaccination coverage compared to the control group, which translated to a reduced hospitalization rate among vaccinated students. The intervention group demonstrated increased vaccination coverage compared to control schools, which translated to a reduced hospitalization rate among vaccinated students (Table 4).

Ferro (2) conducted a cross-sectional comparative study on psychological distress among adolescents and young adults with physical illnesses, such as asthma or epilepsy. This study compared data from 7,342 healthy adults with data from 1,798 with asthma and 117 with epilepsy. Both patient categories had a higher risk of psychological distress. People with asthma experienced 1.94 times higher odds of psychological distress than those without asthma (p < 0.0001) (Table 4).

These studies show that respiratory infections impact physical and mental health, with high rates of clinically diagnosed depression and anxiety observed in affected populations. Implementing preventive measures such as vaccination and early intervention could significantly mitigate the psychological impact associated with these respiratory diseases (25).

Medical interventions, including vaccines, may be associated with psychiatric conditions such as attention deficit hyperactivity disorder (ADHD) (26). A study conducted by Szakács et al. (9) enrolled patients with narcolepsy, which developed in a few people after H1N1 vaccination. Of the 38 patients evaluated, 43% in the vaccinated group had psychiatric comorbidities, including 29% with ADHD (inattentive type); 20% with mood disorders, particularly major depressive disorder; and 10% with general anxiety disorder. Furthermore, temper tantrums were noted at a high frequency (94%) in the vaccinated group (Table 4).

Although mean full-scale IQ scores remained within the normal range for both vaccinated and unvaccinated groups, individuals with psychiatric comorbidities demonstrated lower IQ scores than those without such conditions (9). This indicates that despite the absence of apparent cognitive decline in some patients, active psychiatric disorders can negatively impact cognitive functioning, including verbal comprehension and working memory. This impairment may be influenced by specific medical interventions, including vaccinations.

McLean et al. (8) compared the severity of confirmed laboratory cases of influenza infection among school-aged children with and without asthma. Among 1,764 children with medically attended influenza, 287 (16%) had confirmed asthma (Table 4). The study also concluded that the incidence rate of severe complications from influenza was the same for children with and without asthma. Children with asthma were 1.35 times more likely to be hospitalized or suffer from pneumonia than children without asthma (AOR 1.35). However, children with respiratory disorders should not be automatically assumed to be at greater risk of severe influenza and its complications. Additionally, their mental health should be monitored as they cope with chronic diseases.

Tunde-Ayinmode (19) conducted a study involving 75 children aged 7–14 years diagnosed with bronchial asthma attending clinics at the University of Ilorin Teaching Hospital in Nigeria. The assessment included the Child Behavior Questionnaire and a semi-structured questionnaire to determine psychological and social factors associated with asthma. The findings showed that 25% of children presented with probable psychological morbidity. The study also established that asthma had the following social impact: limitation in play (60% of respondents), disruption of domestic work (49%), fear of dying (29%), and feeling like a burden to the family (25%). Moreover, psychological morbidity was associated with maternal education (p = 0.020), maternal occupation (p = 0.038), polygamy (p = 0.012), and spousal support (p = 0.012). Logistic regression analysis revealed that perceived inadequate spousal support and low maternal occupational levels were additional predisposing factors for psychological morbidity in these children (Table 4).