|Ahead of print
|Incidence and seasonal variation of hospital admissions for acute bronchiolitis among children less than 2 years in a Northern Emirates hospital
Balsam Qubais Saeed1, Hanan Abdulgader Sharif2, Rula Al-Shahrabi3, Ahmed Omar Adrees3, Zainab Mansour Alkokhardi3
1 Clinical Sciences Department, College of Medicine, University of Sharjah, Sharjah, UAE; Research Institute of Medical & Health Sciences (RIMHS), University of Sharjah, Sharjah, UAE
2 Pediatrics and Neonatology Department, University Hospital Sharjah, Sharjah, UAE
3 College of Medicine, University of Sharjah, Sharjah, UAE
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|Date of Submission||08-Mar-2022|
|Date of Decision||30-May-2022|
|Date of Acceptance||03-Jun-2022|
|Date of Web Publication||08-Jul-2022|
Background: There is limited information about acute bronchiolitis (AB) in the United Arab Emirates. The study aims to describe incidents, hospitalizations, and seasonal variation of AB among children less than 2 years. Methods: The retrospective data were collected for children ≤24 months who were admitted in the University Hospital Sharjah with AB from January 1, 2018 to December 31, 2019. Demographic characteristics, vital signs, management, admission data, cases seasonality, maternity history, and co-infections related to the cases were analyzed. Results: A total of 2496 AB cases were reported. Males and children more than 6 months were more infected than females and infants ≤ 6 month. Most of the cases were from emergency room, discharged within the same day and delivered by normal vaginal delivery. Respiratory syncytial virus (RSV) was the commonest cause of AB. Other etiological agents included influenza viruses, adenoviruses, Streptococcus spp., and Mycoplasma pneumoniae. The seasonal variation peak of AB for the 2 years was found in the Autumn months, with a small peak reported in the beginning of Spring months. The number of AB cases in 2019 was greater than that in 2018. Conclusion: AB is a common reason for hospitalization among males and children more than 6 months during the Autumn season. RSV is the common responsible virus for hospital admissions and morbidity. Our results may guide effort toward healthcare provision and implementation of AB prevention.
Keywords: Acute bronchiolitis, infants, respiratory tract infection, seasonality, University Hospital Sharjah UAE
|How to cite this URL:|
Saeed BQ, Sharif HA, Al-Shahrabi R, Adrees AO, Alkokhardi ZM. Incidence and seasonal variation of hospital admissions for acute bronchiolitis among children less than 2 years in a Northern Emirates hospital. Adv Biomed Health Sci [Epub ahead of print] [cited 2022 Aug 8]. Available from: http://www.abhsjournal.net/preprintarticle.asp?id=350312
| Background|| |
Acute bronchiolitis (AB) is a viral infection targeting bronchioles in the lung and causes narrowing of air ways; at first, the virus causes an infection in the upper respiratory tract. This includes the nose, mouth, and throat. It then spreads downward into the trachea and lungs. The virus causes inflammation and even death of the cells inside the respiratory tract. This blocks airflow in and out of the child’s lungs. AB is considered one of the most common causes of hospital admission in infants and young children on a global basis . It has been associated with increasing morbidity and health costs during recent decades . Symptoms can be a productive cough, reduced oral intake, severe wheezing, and sometimes difficulty breathing. However, chronic conditions of the patients such as immunodeficiency, congenital heart disease, and lung disease can aggravate symptoms severity . Premature neonates and age-related factors according to Nenna et al.  can identify symptoms severity as infants below the age of 6 months are more susceptible for co-infection while recurrent wheezing can develop in colder months.
AB can be combined with viral or bacterial infections. About 30% of the cases are co-infected with more than one kind of viruses; respiratory syncytial virus (RSV) considers the main virus in all AB cases, and other viruses that can be associated with AB disease are influenza virus, rhinovirus, and adenovirus . In contrast, Streptococcus pneumoniae, Mycoplasma pneumonia, Staphylococcus aureus, Haemophilus influenza, and Moraxella More Details catarrhalis are common bacterial co-infections which in severe cases can increase infants’ need for mechanical ventilation and lead to prolonged hospitalization stay .
As AB known as seasonal infection, the peak onset can be seen in Winter until the end of the Spring. The seasonal peak of AB may vary from country to country, and temperate countries with high relative humidity and temperature have reported more year-round viral and/or bacterial transmission [3,7]. Among Saudi Arabian infants, up to 88% of the AB cases are due to RSV with peak admission from December to February .
In UAE, limited data on the infection, incidence, and etiology are available. Our study aimed to describe the features of AB: incidents, hospitalizations, and seasonal variation among children less than 2 years.
| Materials and methods|| |
We performed an observational retrospective study by reviewing medical reports of children less than 48 months of age who were admitted with AB to the University Hospital Sharjah (UHS) from January 1, 2018 to December 31, 2019.
A total of 2496 AB cases were reviewed using the hospital track care system. Each infant had only one hospital number which was initially entered to find out child’s clinical presentation and admission to the pediatric emergency department, outpatient clinics (OPCs), pediatric wards (PWs), or neonate’s intensive care unit. Demographic characteristics, vital signs, management, admission data, cases seasonality, maternity history, and co-infections related to cases were also recorded.
Inclusion criteria of participants were hospital admission, respiratory tract symptoms, less than 24 months of age, and positive diagnosis with AB. Exclusion criteria were underlying chronic conditions (cardiac, neurologic, and lung diseases, prematurity, and immunodeficiency) and children’s patients more than 2 years.
Statistical Package for the Social Sciences (SPSS) version 22.0 (SPSS Inc., Chicago, IL, USA, 2013) was used to carry out descriptive statistics of 2637 AB cases for demographics and clinical variables such as gender, age, cases per year, nationality, management, days of hospitalization, method of delivery, and co-infection status. Data have been represented by frequencies and percentages. Consequently, a χ2 test was performed to assess the association between AB incidence per year and demographic characteristics, co-infection, and seasonality. A P-value of less than 0.05 was considered statistically significant.
| Results|| |
A total of 2637 cases were admitted in UHS from January 1, 2018 to December 31, 2019. [Table 1] shows the demographic data and clinical characteristics of all the children who took part in this study. Males made up more than half of the verified AB cases (1557, 59%), and females made up the remaining (1080, 41%). The number of children older than 6 months (1624, 61.6%) was higher than the number of infants less than 6 months (1013, 38.4%). Most of the cases were reported in 2019 (1727, 65.5%), and the rest were reported in 2018 (910, 34.5%). Moreover, the majority of the children (2353, 89.2%) were Emiratis, whereas 284 (10.8%) were non-Emiratis. However, around two-thirds of the cases (1762, 66.8%) were admitted to the emergency department (ED), whereas 630 cases (23.9%) were taken to the OPC. The PW received 236 children (8.9%), and 9 children (0.3%) were admitted to the neonatal intensive care unit (NICU). The majority of the cases (2451, 92.9%) were discharged within the same day, whereas 186 children (7.1%) had to be hospitalized. More than three-quarters of the children (2211, 83.9%) were delivered by normal vaginal delivery (NVD), whereas 426 (16.1%) were delivered by the cesarean section.
|Table 1: Demographic data and clinical features of bronchiolitis patients (N = 2637).|
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[Table 2] lists the bacterial and viral co-infections that were found in 574 of the 2637 patients (21.8%). Around 15 patients (0.6%) were infected with bacterial agents. The most common bacterial co-infection pathogen was Streptococcus group A (8, 0.3%), followed by Diphtheroid species (2, 0.1%), methicillin-resistant S. aureus (MRSA) (2, 0.1%), Staphylococcus species (2, 0.1%), and a single M. pneumoniae case (0.03%). The table also illustrates the viral co-infection pathogens which make up most of the co-infection cases (559, 21.1%) out of all AB cases. The majority of the co-infected cases (497, 18.8%) were infected with RSV, whereas 36 (1.3%) of the cases got infected with Influenza A virus and 18 (0.7%) got Influenza B virus. Moreover, around 7 (0.3%) were infected with Influenza A and Influenza B viruses, whereas a single case (0.03%) was co-infected with rotavirus/adenovirus.
|Table 2: Co-infection among hospitalized children with suspected acute bronchiolitis (N = 2637).|
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Association between AB cases with demographic characteristics, viral co-infections, and seasonality
[Table 3] shows that the patients who were admitted with AB in 2019 (1727, 65.5%) were more than those in 2018 (910, 34.5%). Males occupied more than half of the cases, with 58.7% and 59.2% in both 2018 and 2019, respectively.
|Table 3: Association between acute bronchiolitis admissions and demographic characteristics, co-infection, and seasonality.|
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Significantly, the patients aged >6 months (1624, 61.6%) were more than the infants who were aged <6 months (1013, 38.4%). However, in 2018, the admissions of patients <6 months (45.2%, P<0.00) were more than those who were admitted in 2019 (34.9%, P<0.00), whereas those aged >6 months were more in 2019 than 2018, with the percentages of 65.1% (P<0.00) and 54.8% (P<0.00), respectively.
Patients in emergency department admissions were significantly more frequent in 2019 (1240, 71.8%, P<0.00) than in (522, 57.4%, P<0.00) 2018, whereas the patients in OPC admissions were more in 2018 (33.5%, P<0.00) than in 2019 (18.8%, P<0.00). Hospitalization and ward admission showed no significant difference, with 8.6% (P<0.00) and 9.1% (P<0.00) staying in the PW in 2018 and 2019, respectively. Moreover, in 2018, 5 (0.6%, P<0.00) patients stayed in the NICU, whereas in 2019, they were 4 (0.2%, P<0.00) patients.
Regarding the delivery method, there were no significant variations between the admission years, but with a minor difference. NVD cases were slightly more during 2018 (86.5%, P<0.008) when compared with 2019 (82.5%, P<0.008). Moreover, admissions due to cesarean delivery cases were a little higher during 2019 (17.5%, P<0.008) than during 2018 (13.5%, P<0.008).
The most predominant cause of co-infections was RSV for both the years. However, the numbers were higher in 2019 with 21.9% (P<0.00) of the cases, compared with 12.96% (P<0.00) of the cases in 2018. Influenza A virus affected 16 cases in 2019 (0.9%, P < 0.00), and only a single case in 2018 (0.1%, P<0.00). Furthermore, Influenza B virus was found in 15 cases in 2019 (0.9%, P<0.00) and in 3 cases in 2018 (0.3, P<0.00). Nevertheless, Influenza A + B affected five cases in 2018 (0.55%, P<0.00) and only two cases in 2019 (0.1%, P<0.00).
Seasonality of AB in the UAE
As demonstrated in [Figure 1], the seasonal peak of AB during the 2 years was in the Autumn season. However, the line graph revealed that the rate in 2019 began to grow in September and lasted until November, with the largest peak occurring in November. As shown in [Table 3], the total cases for Autumn 2018 were 351 (38.6%, P<0.00), and for Autumn 2019 the cases were more (889, 51.5%, P<0.00). Winter had the second place with 303 (33.3%, P<0.00) during 2018 and 356 (20.6%, P<0.00) during 2019. As [Figure 1] shows, a small peak presented in the beginning of Spring for both the years and caused a slight rise in the number of cases, with 1741 (9.1%, P<0.00) cases in 2018 and 2951 (7.1%, P<0.00) cases in 2019, respectively. Summer had the least number of admitted cases, with 82 (9.01%, P<0.00) and 187 (10.8%, P<0.00) in 2018 and 2019, respectively. According to the same figure, the number of cases in 2019 was greater than that in 2018.
|Figure 1: Distribution of acute bronchiolitis cases among children who visited University Hospital Sharjah between 2018 and 2019.|
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| Discussion|| |
AB is the most leading cause of pediatric admissions to the hospitals; cases are seen year-round with seasonal patterns. The burden of AB has differed when it comes to geographic locations. However, UAE is located in subtropics, southern regions in the tropics. It has a desert climate with hot summers (April to September) and mild winters (October to March). Although such illness in temperate countries is common and clearer in the Winter season, trends among tropical and sub-tropical countries are changing from region to region .
In our study, AB showed almost a double rise in the number of cases between the two years of this study (34.5% in 2018 and 65.5% in 2019); the incidence of AB among children in UAE was in the range of previous publications in Puerto Rico, Malaysia, and Singapore ,,. Factors behind this increment could be related to low birth weight, lack of breastfeeding, and vitamin deficiency such as vitamin D, calcium and zinc, immunosuppression, and lack of immunization .
Our findings showed that the male gender is more susceptible to be infected than females; in this line, Ahmed et al.  also reported that 51–69% of male infants with acute respiratory tract infection are commonly more affected than females. Many studies have reported that the male gender is associated with high incidence daycare visits and severe symptoms such as wheezing ,,. Hormonal and genetic effects on the immune system in an early stage can be an explanation for infections between males and females . However, there is no significant difference in gender with increased AB cases in this study.
Incidence of AB is predominantly seen in children below 24 months of age . Our findings report that the hospitalization rate is higher in infants over 6 months of age. Other studies reported that younger ages (≤6 months) had the highest incidence rate of severe infectious diseases with also high burden among older ages [4, 19, 20].
The current study found that in both years, most of the children’s hospitalization was in an emergency room and they have discharged within the same day which indicates short hospitalization length; most of the cases came with mild symptoms and self-limiting conditions. Other outcomes from Rodríguez-Martínez et al.  and Alharbi et al.  showed longer duration of stay (3–5) and (1–8) days, respectively. In 2019, numbers of infant’s hospitalization to the emergency room were higher and there were fewer NICU admissions compared with the year before. The same findings have been found with Najioullah et al. .
Our results showed a statistical significance between cesarean and vaginal born babies who were infected by AB, in line with our findings Alterman et al.  reported an increased risk of severe bronchiolitis in infants born by cesarean when compared with vaginal delivery. Some researchers attributed this to gut microbiota, which might leave them more susceptible to respiratory infections in the first 5 years of life .
The co-infection rate in our findings was 21.76%; other studies reported a higher rate of co-infection with a longer hospital stay, and severity due to bacterial co-infection is associated with RSV infections ,,. In this study, RSV was found to be the main cause of AB (12.96% and 21.9% in 2018 and 2019, respectively). A study by Ahmed et al.  showed that up to 54% of acute respiratory infections seen in Saudi Arabia were due to RSV during the years 1991–2015. In the same line, Al Shibli et al.  reported that in AB cases, RSV is the primary pathogen responsible for hospital admissions.
An initial objective of this study was to identify the seasonality pattern of AB in UAE; however, our study was conducted on northern parts of the UAE which consider a subtropical zone characterized with warm-to-hot weather all year round, rare rainy season, and 61.3% average annual relative humidity rate . The warmest month of the year is August, with an average temperature of 35.7°C. In January, the lowest average temperature of the whole year is 19.4°C . Our findings reported a high incidence of AB during Autumn and Winter with a noticeable peak during Autumn months (September–November) and a second peak in Winter (December–mid of March). Findings in a reviewed article by Suryadevara and Domachowske  showed the epidemiology and seasonality of childhood respiratory viruses in the tropics. Different peaks around the year reported, for instance, in Malaysia can be seen from September to November; another study mentioned was in Qatar with two peaks: November–December and May–September. In this line, another study in Saudi Arabia has a remarkable Winter peak starting from December to early March . The common hypothesis that relates respiratory viruses and climate in young children, especially in the Winter season, might be referred to immature immunity.
| Conclusion|| |
In the 2 consecutive years studied, a higher number of hospital admissions for AB among infants or children aged less than 2 years was noted during the Autumn season (September to November) with a small peak presented in the beginning of Spring for both years 2018 and 2019. The most common infections among infants seeking care in unscheduled medical visits for AB were RSV and Influenza. Our results may guide effort toward healthcare provision and implementation of AB prevention.
Our study was subject to some limitations. First, this study was in a single hospital; it may not be generalizable to the entire population of the UAE because most of the patients were taken from children less than 2 years in the Emirate of Sharjah only. In addition, this study only covered 13 months. More studies need to confirm the policies regarding prophylaxis against the causes of AB; these studies need to be based on much wider data regarding populations, children under risk, seasonality, and relative cost–benefit relationships.
We thank all staff in the Department of Pediatrics, University Hospital Sharjah (UHS).
BQS was responsible for conceptualization; methodology; and writing—original draft preparation, reviewing, and editing. HAS was responsible for study design; methodology; and reviewing and editing. RA-S was responsible for statistical analysis and writing. AOA was responsible for methodology, reviewing, and proofreading. ZMA was responsible for writing, reviewing, and editing.
This study was conducted as a collaboration between the Sharjah Institute for Medical Research and the University Hospital Sharjah and it was approved by the Ethics and Research Committee in the University Hospital Sharjah with a reference number (UHS-HERC-030-29022020).
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
Data availability statement
All data are available in this article.
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Balsam Qubais Saeed,
Clinical Sciences Department, College of Medicine, University of Sharjah, Sharjah
Source of Support: None, Conflict of Interest: None
[Table 1], [Table 2], [Table 3]
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