Discussion
COVID-19 nearly erased bronchiolitis and RSV infections within our
emergency department during the first year of the pandemic, with over
80% reduction in bronchiolitis visits from the year prior. While all ED
visits fell, the proportion of visits due to bronchiolitis also
decreased. The marked decline in respiratory illness is likely
multi-factorial and is hypothesized to be largely driven by social
distancing, hand hygiene, masking, and Stay at Home Orders [11].
This trend was also noted in other parts of the world including Belgium,
New Zealand, Brazil, France, and the US [12-15]. While other studies
have focused on ICU patients or all cause ED visits, this study adds
detailed information with a large cohort of bronchiolitis ED visits in
the Southeastern US with measures of resource utilization and changes in
virology as cases of bronchiolitis fell dramatically and then rose
sharply.
The 2014 AAP Guidelines for the management of bronchiolitis recommends
against routine chest radiographs and albuterol use [1]. Despite
this, over use still occurs in many hospitals. The pandemic brought
about many changes in how respiratory illnesses were acutely managed due
to the novelty of COVID-19 and fears that it would be more severe in
young children. However, none of the patients in 2020-2021 actually
tested positive for COVID. Increased use of high flow, albuterol, chest
radiographs and ICU admissions for bronchiolitis were seen during the
lower volume period when rhinovirus was the dominant pathogen detected.
Other studies have shown that providers are more likely to utilize
diagnostic tests and medications once high flow is initiated, and
increased use of low value care for bronchiolitis during lower census
periods has been described [18, 19]. Prior studies have not shown an
increase in bronchiolitis severity during this time [20]. In
2021-2022, 31% of patients tested had COVID, a substantial increase
likely reflecting increased lower respiratory symptoms with changing
variants, but albuterol and decreased. The resurgence of bronchiolitis
after such a dramatic decrease means this disease is likely never going
to completely disappear. Ironically, concentrating quality improvement
efforts into periods of low census for a disease may have more impact.
This hospital saw a stark change in the virology of patients seen in the
ED with bronchiolitis over the course of the study period. There was an
initial disappearance of RSV in the first year of the pandemic with only
four RSV cases identified in 2020 among our study population. An
atypical summer spike in RSV in 2021 followed, which is likely the
primary driver in the increased bronchiolitis visits. The summer ED
visits were almost as high as the winter of the last typical season in
2019. During the low volume year of 2020, rhino/enterovirus was the
predominant virus detected by percentage, though the raw number detected
was relatively similar to previous years. It is possible that more
rhinovirus was detected due to higher testing rates, which increased by
23% from the year prior. Rhinovirus is often found to be a co-infection
with a large number of asymptomatic carriers but is also known to cause
bronchiolitis, especially associated with wheezing, and may be an early
predictor of asthma [21-24]. It is possible that more albuterol was
used during this time due to more rhino/enterovirus induced wheezing
heard on exam.
The dominance of rhino/enterovirus during the emergence of the pandemic
and the disappearance of RSV raises important questions about how the
transmission of this virus was affected by efforts to slow the spread of
COVID. RSV is an enveloped, single‐stranded, negative‐sense RNA virus of
the Pneumoviridae family and is transmitted via droplet [24].
Because of its enveloped structure, RSV is more affected by hand washing
then the non-enveloped structure of rhinovirus, which has a moderate
resistance to hand sanitizer [24, 25]. RSV’s main reservoir is in
chronic obstructive pulmonary disease and immunocompromised hosts,
whereas rhinovirus is often carried and spread by asymptomatic healthy
children [1, 25]. Hand washing was heavily stressed as a
non-pharmaceutical intervention during the pandemic and could have
decreased RSV transmission but would not have the same impact on
rhinovirus. The relative resilience of rhinovirus during the pandemic
likens it to the cockroach of viruses- one that never completely
disappears and survives most extinguishing efforts.
Immunity to RSV is complex. For infants, the transfer of maternal
antibodies can help protect them in the first couple months of life
[27]. Adults also need continued antigenic exposure, as it has been
shown there is a loss of RSV-specific IgA memory B-cells, usually in the
summer months when RSV is dormant [27]. It is reasonable to
hypothesize there was decreased maternal antibody transfer to infants by
mothers who were pregnant during the early COVID pandemic and were not
being exposed to RSV antigens. Therefore it is not surprising there was
a large, atypical RSV spike in the summer of 2021 (Figure 2) when there
was likely a large population of infants and toddlers who were
immunologically naïve to RSV being exposed for the first time. As COVID
precautions relaxed in the spring of 2021, RSV was able to have a strong
resurgence. The rise in bronchiolitis visits in the summer of 2021 also
followed the end of the state mask mandate in this state, which expired
in April of 2021. In the future, we will see if this shift in RSV
seasonality persists with bronchiolitis becoming a relatively steady
year-round illness, or return to previous seasonal norms. This could
influence the timing of Synagis given to eligible infants, as it is
currently only available during the winter months. It also remains to be
seen if other Sars-CoV-2 variants will cause more respiratory illness in
this population, as is suggested by the upwards trend in 2021-2022.
This study is limited by being a single-institution, retrospective
study. The diagnosis of bronchiolitis was based on ICD-10 coding only
and testing from other sources prior to admission were not included. The
increased ICU admission rate for bronchiolitis is difficult to interpret
as ICU admission criteria changed such that all patients on high flow
nasal cannula were admitted to the ICU instead of the step-down unit
until their COVID test resulted until November 2020, though the numbers
were very small. During 2021 this hospital participated in a Value in
Inpatient Pediatrics high flow initiation reduction quality improvement
project (HIFLO), which may account for some of the decreased high flow
rate from 2020 to 2021. Internal quality improvement projects targeted
albuterol use which likely accounts for the sharp decrease from 2017 to
2018.
In summary, COVID-19 had a significant impact on bronchiolitis emergency
department visits in overall number, admission rates, an increase in low
value care, and virology, while not being the predominant driver of
respiratory disease in young children.
References
1. Diagnosis and management of bronchiolitis. Pediatrics.
2006;118(4):1774-93. doi: 10.1542/peds.2006-2223.
2. Joseph MM, Edwards A. Acute bronchiolitis: assessment and management
in the emergency department. Pediatr Emerg Med Pract. 2019;16(10):1-24.
Epub 2019/09/27.
https://www.ebmedicine.net/topics/respiratory/pediatric-bronchiolitis
3. Ralston SL, Lieberthal AS, Meissner HC, Alverson BK, Baley JE,
Gadomski AM, Johnson DW, Light MJ, Maraqa NF, Mendonca EA, Phelan KJ,
Zorc JJ, Stanko-Lopp D, Brown MA, Nathanson I, Rosenblum E, Sayles S,
3rd, Hernandez-Cancio S. Clinical practice guideline: the diagnosis,
management, and prevention of bronchiolitis. Pediatrics.
2014;134(5):e1474-502. doi: 10.1542/peds.2014-2742.
4. Curatola A, Lazzareschi I, Bersani G, Covino M, Gatto A, Chiaretti A.
Impact of COVID-19 outbreak in acute bronchiolitis: Lesson from a
tertiary Italian Emergency Department. Pediatr Pulmonol.
2021;56(8):2484-8. doi:10.1002/ppul.25442.
5. Kenmoe S, Kengne-Nde C, Ebogo-Belobo JT, Mbaga DS, Fatawou Modiyinji
A, Njouom R. Systematic review and meta-analysis of the prevalence of
common respiratory viruses in children < 2 years with
bronchiolitis in the pre-COVID-19 pandemic era. PLoS One.
2020;15(11):e0242302. doi:10.1371/journal.pone.0242302.
6. Pelletier JH, Au AK, Fuhrman D, Clark RSB, Horvat C. Trends in
Bronchiolitis ICU Admissions and Ventilation Practices: 2010-2019.
Pediatrics. 2021 Jun;147(6):e2020039115. doi: 10.1542/peds.2020-039115.
Epub 2021 May 10. PMID: 33972381; PMCID: PMC8785748
7. Franklin D, Babl FE, Schlapbach LJ, Oakley E, Craig S, Neutze J,
Furyk J, Fraser JF, Jones M, Whitty JA, Dalziel SR, Schibler A. A
Randomized Trial of High-Flow Oxygen Therapy in Infants with
Bronchiolitis. N Engl J Med. 2018 Mar 22;378(12):1121-1131. doi:
10.1056/NEJMoa1714855. PMID: 29562151
8. Kepreotes E, Whitehead B, Attia J, Oldmeadow C, Collison A, Searles
A, Goddard B, Hilton J, Lee M, Mattes J. High-flow warm humidified
oxygen versus standard low-flow nasal cannula oxygen for moderate
bronchiolitis (HFWHO RCT): an open, phase 4, randomised controlled
trial. Lancet. 2017 Mar 4;389(10072):930-939. doi:
10.1016/S0140-6736(17)30061-2. Epub 2017 Feb 2. PMID: 28161016.
9. Byrd C, Noelck M, Kerns E, Bryan M, Hamline M, Garber M, Ostrow O,
Riss V, Shadman K, Shein S, Willer R, Ralston S. Multicenter Study of
High-Flow Nasal Cannula Initiation and Duration of Use in Bronchiolitis.
Hosp Pediatr. 2023 Apr 1;13(4):e69-e75. doi: 10.1542/hpeds.2022-006965.
PMID: 36938609.
10. DeLaroche AM, Rodean J, Aronson PL, Fleegler EW, Florin TA, Goyal M,
Hirsch AW, Jain S, Kornblith AE, Sills MR, Wells JM, Neuman MI.
Pediatric Emergency Department Visits at US Children’s Hospitals During
the COVID-19 Pandemic. Pediatrics. 2020. Epub 2020/12/29.
doi:10.1542/peds.2020-039628.
11. Goldman RD, Grafstein E, Barclay N, Irvine MA, Portales-Casamar E.
Paediatric patients seen in 18 emergency departments during the COVID-19
pandemic. Emerg Med J. 2020;37(12):773-7.
doi:10.1136/emermed-2020-210273.
12. Friedrich F, Ongaratto R, Scotta MC, Veras TN, Stein R, Lumertz MS,
Jones MH, Comaru T, Pinto LA. Early Impact of social distancing in
response to COVID-19 on hospitalizations for acute bronchiolitis in
infants in Brazil. Clin Infect Dis. 2020. doi:10.1093/cid/ciaa1458.
13. Flores-Pérez P, Gerig N, Cabrera-López MI, de Unzueta-Roch JL, Del
Rosal T, Calvo C. Acute bronchiolitis during the COVID-19 pandemic.
Enferm Infecc Microbiol Clin (Engl Ed). 2021.
doi:10.1016/j.eimc.2021.06.012.
14. Trenholme A, Webb R, Lawrence S, Arrol S, Taylor S, Ameratunga S,
Byrnes CA. COVID-19 and Infant Hospitalizations for Seasonal Respiratory
Virus Infections, New Zealand, 2020. Emerg Infect Dis. 2021;27(2):641-3.
doi:10.3201/eid2702.204041.
15. Van Brusselen D, De Troeyer K, Ter Haar E, Vander Auwera A, Poschet
K, Van Nuijs S, Bael A, Stobbelaar K, Verhulst S, Van Herendael B,
Willems P, Vermeulen M, De Man J, Bossuyt N, Vanden Driessche K.
Bronchiolitis in COVID-19 times: a nearly absent disease? Eur J Pediatr.
2021;180(6):1969-73. doi:10.1007/s00431-021-03968-6
16. Yeoh DK, Foley DA, Minney-Smith CA, Martin AC, Mace AO, Sikazwe CT,
Le H, Levy A, Blyth CC, Moore HC. The impact of COVID-19 public health
measures on detections of influenza and respiratory syncytial virus in
children during the 2020 Australian winter. Clin Infect Dis. 2020. Epub
2020/09/29. doi:10.1093/cid/ciaa1475
17. Wilder JL, Parsons CR, Growdon AS, Toomey SL, Mansbach JM. Pediatric
Hospitalizations During the COVID-19 Pandemic. Pediatrics. 2020;146(6).
Epub 2020/11/05. doi: 10.1542/peds.2020-005983.
18. Biggerstaff S, Markham JL, Winer JC, Richardson T, Berg KJ. Impact
of High Flow Nasal Cannula on Resource Utilization in Bronchiolitis.
Hosp Pediatr. 2021. doi: 10.1542/hpeds.2021-005846.
19. Andrews C, L Maxwell S, Kerns E, McCulloh R, Alverson B. The
association of seasonality with resource utilization in a large national
cohort of infants with bronchiolitis. Hosp Pediatr. 2021;11(2):126-134.
doi: 10.1542/hpeds.2020-0120
20. Shanahan KH, Monuteaux MC, Bachur RG. Severity of Illness in
Bronchiolitis Amid Unusual Seasonal Pattern During the COVID-19
Pandemic. Hosp Pediatr. 2022 Apr 1;12(4):e119-e123. doi:
10.1542/hpeds.2021-006405. PMID: 35352128.
21. Esposito S, Daleno C, Tagliabue C, Scala A, Tenconi R, Borzani I,
Fossali E, Pelucchi C, Piralla A, Principi N. Impact of rhinoviruses on
pediatric community-acquired pneumonia. Eur J Clin Microbiol Infect Dis.
2012;31(7):1637-45. doi:10.1007/s10096-011-1487-4.
22. Vandini S, Biagi C, Fischer M, Lanari M. Impact of Rhinovirus
Infections in Children. Viruses. 2019;11(6). Epub 2019/06/15.
doi:10.3390/v11060521.
23. Jackson DJ, Gangnon RE, Evans MD, Roberg KA, Anderson EL, Pappas TE,
Printz MC, Lee WM, Shult PA, Reisdorf E, Carlson-Dakes KT, Salazar LP,
DaSilva DF, Tisler CJ, Gern JE, Lemanske RF, Jr. Wheezing rhinovirus
illnesses in early life predict asthma development in high-risk
children. Am J Respir Crit Care Med. 2008;178(7):667-72. doi:
10.1164/rccm.200802-309OC.
24. Kotaniemi-Syrjänen A, Vainionpää R, Reijonen TM, Waris M, Korhonen
K, Korppi M. Rhinovirus-induced wheezing in infancy–the first sign of
childhood asthma? J Allergy Clin Immunol. 2003;111(1):66-71.
doi:10.1067/mai.2003.33.
25. Di Mattia G, Nenna R, Mancino E, Rizzo V, Pierangeli A, Villani A,
Midulla F. During the COVID-19 pandemic where has respiratory syncytial
virus gone? Pediatr Pulmonol. 2021;56(10):3106-9.
doi:10.1002/ppul.25582.
26. Savolainen-Kopra C, Korpela T, Simonen-Tikka ML, Amiryousefi A,
Ziegler T, Roivainen M, Hovi T. Single treatment with ethanol hand rub
is ineffective against human rhinovirus–hand washing with soap and
water removes the virus efficiently. J Med Virol. 2012;84(3):543-7.
doi:10.1002/jmv.23222.
27. Green CA, Sande CJ, de Lara C, Thompson AJ, Silva-Reyes L,
Napolitano F, Pierantoni A, Capone S, Vitelli A, Klenerman P, Pollard
AJ. Humoral and cellular immunity to RSV in infants, children and
adults. Vaccine. 2018;36(41):6183-90. Epub 20180831.
doi:10.1016/j.vaccine.2018.08.056.