The COVID-19 pandemic has had a major impact on healthcare systems throughout the world. As the clinical and epidemiological features of COVID-19 share many similarities with other respiratory viruses in children, ensuring optimal management of different viral respiratory diseases is critical. The precautions taken to prevent COVID-19 have seemingly had an indirect effect on the seasonal variations of viral diseases and the frequency of relevant viruses. The seasonal irregularity of and uncertainty surrounding these infection peaks may affect the clinical prediction and management resources. Therefore, the aim of this study is to evaluate the impact of the COVID-19 pandemic on the frequency and seasonal variation of common respiratory viruses in children pre- and post-pandemic. This study utilizes a descriptive cross-sectional retrospective approach. A total of 726 samples collected from children below 14 years of age and admitted to King Abdulla bin Abdulaziz University Hospital between March 2017 and February 2022 were included in the present study to evaluate the impact of the COVID-19 pandemic on the frequency and seasonal variation of common respiratory viruses in children pre- and post-pandemic. The samples taken before March 15, 2020, were considered pre-COVID-19, and those taken from March 15, 2020, onward were considered post-COVID-19. The seasons were divided based on the months of the year as per the Saudi climate website (winter: December-February, spring: March-April, summer: May-August, and autumn: September-November). All nasopharyngeal swabs (NPS) for viral Polymerase chain reaction (PCR) multiplex that were done for all admitted children of age up to 14 years were included, and the total samples amounted to 726, There were 686 (94.4%) positive samples for viruses and 40 (5.5%) negative samples. The number of positive samples pre-COVID-19 pandemic was 494 (72%), and the number of positive samples post-COVID-19 pandemic was 192 (28%). The frequency of different viruses has decreased post-COVID-19 and seasonality has changed; Although Adenovirus, and influenza viruses have no big changes, but Human Rhino/enterovirus (HRE) has increased frequency post-COVID-19 (49%), while post-COVID-19 it was (29.1%). The seasonal peak for Respiratory Syncytial Virus (RSV) pre-COVID-19 showed mainly in winter (49%), while post-COVID-19 it showed no peak. The frequency of most types of viruses is noted to be lesser in the post-COVID-19 period, most likely due to precautions followed during the pandemic. This is not the case for HRE which showed increasing frequency in post-COVID-19; However, there are clinically and statistically significant differences among seasonal peaks in Respiratory RSV, HRE, and Parainfluenza viruses (PIV) pre- and post-COVID-19 pandemic. RSV showed no peak in different seasons post-COVID-19, although its peak pre-COVID-19 was in winter and autumn; Additionally typical trend of HRE peak changed to be in Autumn and spring post-COVID-19 instead of winter pre-COVID-19.

Background: The COVID-19 pandemic has imposed significant changes on daily life. It negatively impacts children’s physical activity and lifestyle behaviors, which may cause accelerated weight gain during the COVID-19 pandemic. This study aims to evaluate children’s longitudinal age- and sex-adjusted body mass index (BMI) percentile changes during and after the COVID-19 pandemic. Methods: Height and weight data were obtained from electronic medical records for children (ages 2–18) visiting outpatient clinics during three periods: pre-COVID-19 lockdown, during COVID-19 lockdown, and post-COVID-19 lockdown. According to the availability of anthropometric information, three partially overlapping cohorts were formed: Cohort 1 (N = 934, pre- and during lockdown), Cohort 2 (N = 1129, during and post-lockdown), and Cohort 3 (N = 203, data from all three periods). Results: During the lockdown, the mean changes in percentiles of age- and sex-adjusted BMI were 6% ± 0.23, while after the lockdown, there were smaller mean changes in BMI percentiles (1% ± 0.19). There were significant associations of age and the baseline BMI categories with the change in the means of the adjusted BMI percentile of children during and after the COVID-19 pandemic (p-value < 0.001). In addition, there were significant associations of gender and the baseline BMI categories with the change in the means of the adjusted BMI percentile of children over a three-time series (p-value: <0.04, <0.001, respectively). Conclusions: In conclusion, children experienced increased BMI during and after the COVID-19 lockdown. This result highlights the importance of structured interventions to mitigate the consequences during challenging times on children’s health.