Israel Medical Association Journal

Background: During coronavirus disease 2019 (COVID-19) pandemic, less isolation of common winter viruses was reported in the southern hemisphere.

Objectives: To evaluate annual trends in respiratory disease-related admissions in a large Israeli hospital during and before the pandemic.

Methods: A retrospective analysis of medical records from November 2020 to January 2021 (winter season) was conducted and compared to the same period in two previous years. Data included number of admissions, epidemiological and clinical presentation, and isolation of respiratory pathogens.

Results: There were 1488 respiratory hospitalizations (58% males): 632 in 2018–2019, 701 in 2019–2020, and 155 in 2020–2021. Daily admissions decreased significantly from a median value of 6 (interquartile range [IQR] 4–9) and 7 per day (IQR 6–10) for 2018–2019 and 2019–2020, respectively, to only 1 per day (IQR 1–3) in 2020–2021 (P-value < 0.001). The incidence of all respiratory viruses decreased significantly during the COVID-19 pandemic, with no hospitalizations due to influenza and only one with respiratory syncytial virus. There was also a significant decline in respiratory viral and bacterial co-infections during the pandemic (P-value < 0.001).

Conclusions: There was a significant decline in pediatric respiratory admission rates during the COVID-19 pandemic. Possible etiologies include epidemiological factors such as mask wearing and social distancing, in addition to biological factors such as viral interference. A herd protection effect of adults and older children wearing masks may also have had an impact.

Background: Respiratory syncytial virus (RSV)-related bronchiolitis is a common cause of morbidity in young infants. The recommendations for its passive prevention by palivizumab are currently under intensive debate.

Objectives: To elucidate the optimal prevention strategy by studying the morbidity of RSV disease under the current recommendations for palivizumab prophylaxis in Israel.

Methods: We collected demographic and clinical data of all children hospitalized with microbiologically confirmed RSV bronchiolitis during 2015–2016 at Schneider Children's Medical Center. The seasonality of RSV disease was also studied for the period 2010–2017 in sentinel clinics scattered throughout Israel.

Results: Of the 426 hospitalized children, 106 (25%) had underlying diseases but were not eligible for palivizumab prophylaxis according to the current criteria in Israel. Their course was severe, with a mean hospital stay of 6.7 days and a 12% admission rate to the pediatric intensive care unit (PICU). Palivizumab-eligible children who did not receive the prophylaxis before hospitalization had the most severe course, with 22% admitted to the PICU. More children were diagnosed with RSV disease in October than in March among both hospitalized and ambulatory children; 44% of the palivizumab-eligible hospitalized children were admitted in the last 2 weeks of October, before 1 November which is the recommended date for starting palivizumab administration in Israel.

Conclusions: According to the results of the present study we suggest advancing RSV prophylaxis in Israel from 1 November to mid-October. The precise palivizumab-eligible categories should be reconsidered.

Objective: To assess the impact of multiple births on the severity of RSV infection and define risk factors for acquiring RSV infection in infants of multiple birth.

Methods: Clinical data on infants hospitalized with RSV infection between 2008 and 2010 were retrospectively collected.

Results: Twins comprised 7.6% (66/875) of hospitalized infants with RSV bronchiolitis during the study period. Infants in the twin group were younger (122.4 ± 131.7 vs. 204.5 ± 278.8 days, P = 0.014), had a lower mean gestational age (35.3 ± 2.6 vs. 38.6 ± 2.5 weeks, P < 0.001), and were more likely to have been born prematurely compared with singleton infants (65.6% vs. 13%, P < 0.001). On a multivariable logistic regression analysis, young age, early gestational age and male gender were the only variables identified as risk factors for pediatric intensive care unit admission (P < 0.001, P < 0.001 and P = 0.03, respectively). In contrast, the mere fact of a child being a twin was not found to be a significant risk factor for disease severity. In addition, if one twin is hospitalized due to RSV infection, the other has a 34% chance of also being hospitalized with bronchiolitis. Young age was a significant risk factor for hospitalization of the second twin (P < 0.001).

Conclusions: Our findings suggest that twins hospitalized with RSV bronchiolitis do not have an increased risk for severe infection as compared to singletons. However, a twin of an infant hospitalized with RSV infection has a considerable risk of also being hospitalized with bronchiolitis, thus close monitoring is recommended.