Out-of-hospital urgent care (OHUC) services, like in-hospital emergency services, require up-to-date knowledge and skills. Specifically, training on the management of critically ill children is particularly important in OHUC delivery. In particular, acute bronchiolitis (AB) becomes a significant challenge during the seasonal peak, overwhelming human and material resources. In addition to an increase in home visits due to this condition, the frequency of interhospital transport grows exponentially. Such transports involve the transfer of patients from sending hospitals without a paediatric intensive care unit (PICU) to hospitals offering higher levels of care. The OHUC teams of the Community of Madrid provide the following services: (1) primary care: management of the patient at home or in the community, and (2) interhospital transport. Primary care can be delivered through a mobile medical unit (MMU), in the case of non-emergency conditions, or by a mobile intensive care unit (MICU) if the patient requires emergency care. Interhospital transports, depending on the condition and age of the patient, can be carried out in a basic life support ambulance, MICU or by a specialised neonatal transport team (NTT) that, in turn, comprises 2 units: (1) an advanced life support (ALS) team composed of two emergency medical technicians (EMTs) and an OHUC nurse and (2) a unit composed by a neonatologist (routinely involved in the delivery of level III neonatal care and trained in neonatal transport) and one OHUC EMT with specific training in neonatal care.

Thus, primary care is provided by OHUC teams not specialised in neonatology (non-neonatal OHUC) and interhospital transport carried out non-neonatal OHUC teams (patients aged ≥ 29 days) or the NTT (patients aged ≤ 28 days and/or < 44 weeks of postmenstrual age).

Out-of-hospital urgent care settings exclude outpatient urgent health care facilities (hospitals and primary care centres), and only include mobile care teams/ambulances.

During the COVID-19 pandemic, there was a shift in the epidemiology of bronchiolitis, with a sharp drop in the frequency of paediatric hospital admissions for this cause,1–4 with no evidence of increased severity in children with coinfection.4 Most hospital-based studies4–6 compared the characteristics of the patients and their respiratory infections before and during the COVID-19 pandemic. However, despite the abundance of evidence on the impact of the pandemic on the hospital setting, little is known about its impact on OHUC. It would also be interesting to know the impact of the COVID-19 pandemic on the epidemiology of AB, the patient characteristics and neonatal and paediatric transport at the OHUC level. All this information could help organise and manage resources more efficiently during epidemics, in addition to the establishment of effective preventive strategies to control outbreaks.

Thus, the aim of our study was to establish the incidence of bronchiolitis in the different periods between 2016 and 2023 and the main characteristics of neonatal and paediatric patients transported by the OHUC teams of the Community of Madrid, in addition to assessing whether the COVID-19 pandemic has changed epidemiological trends and the characteristics of patients with bronchiolitis.

Multiple studies conducted in the hospital setting have evinced changes in the epidemiology of AB,1–3,11–14 with a nearly negligible incidence in the 2020/2021 season followed by a progressive increase. Although the settings differed, these trends are consistent with the data analysed in our study, which showed a drastic decrease in the incidence of AB during the COVID-19 pandemic, followed by a recovery after the 6th wave, when it increased beyond the incidence of all other seasons under study.

Another interesting phenomenon observed after the pandemic in other countries, like Italy4 or France,14 was the delay in the peak of hospital admissions due to bronchiolitis, also reported in Spain in regions like Andalusia,15 where, in the post-pandemic period, hospital admissions peaked in the summer months, whereas before the COVID-19 pandemic this peak took place in January-February. Our findings were similar, with an unusual surge of cases in June 2021 following the 4th wave of the COVID-19 pandemic.

As for age, after the COVID-19 pandemic, the median age was 18 days in the NTT group and 3.2 months in the non-neonatal OHUC group. Comparing this with other studies, and despite the differences in care setting, the median age observed in the non-neonatal OHUC group was similar to the one reported by Loconsole et al.4 (4 months) and Guitart et al.6 (2 months).

In the non-neonatal OHUC group, the median age increased in the 2020/2021 season, which could be explained by the home confinement measures implemented at the beginning of the pandemic. Since children had not developed immunity against respiratory viruses due to the lockdown, those who would have already had bronchiolitis presented this type of infection once they were exposed to the viruses again, which was later than usual.

Although the percentage of severe cases was greater in the NTT group, our study did not find an association between age or preterm birth and severity, which has been described in previous studies, for instance, by Guitart et al.,6 who found an association between disease severity and preterm birth.

The severity score was higher in the group of neonatal patients transported by the NTT, however, there was a smaller proportion of patients managed with IMV compared to the non-neonatal OHUC group. This can be explained by the fact that OHUC teams chiefly provide primary care, and that, if the patient becomes unstable at home or during transport, these teams do not have the capacity to deliver NIMV to children with weights of less than 5 kg, and thus need to step up to IMV directly. On the other hand, interhospital transports carried out by the NTT sometimes involve tertiary care hospitals with limitations for the delivery of NIMV, leading to the maintenance of HFOT in severe patients. Stabilization with NIMV upon arrival of the NTT would allow improving the clinical condition of the patient without requiring IMV. To this, we must add the experience in the delivery of this modalities of respiratory support and in managing this type of patient of neonatal and paediatric transport teams. This highlights the importance of allocating the necessary material resources to OHUC teams and especially of the training in the management of this type of patients and of diseases.

As regards the use of salbutamol in the non-neonatal OHUC group, it decreased significantly in the last few seasons, but still was used in a percentage that needs to be taken into account. Improved training on the diagnosis of bronchiolitis after the pandemic, including DO NOT DO recommendations, and the frequent use of salbutamol for the bronchial challenge test in out-of-hospital settings in children aged more than 6 months would explain the pattern of use in the last few seasons.

At present, there is no effective pharmacological treatment for AB. The meta-analyses that have analysed the currently used treatment options, like salbutamol, budesonide, adrenaline, hypertonic saline solution, corticosteroids or antibiotics have not found evidence supporting their use.16 As a result, clinical practice guidelines11,17 discourage these treatments. This evinces the importance of developing management protocols for these patients and providing regular training to avoid the use of unnecessary drugs, as has been done in other care settings.16 Such protocols would also help optimise the use of resources during seasonal outbreaks.

In conclusion, based on the reported findings, the following would be important measures to implement in the future: (1) epidemiological surveillance to anticipate surges in health care demand by this type of patients and to improve resource management in each seasonal campaign, optimization of health care and use of preventive measures, such as hand hygiene, face masks and social distancing, and (2) development of training and management protocols for OHUC teams, training professionals to optimise and streamline care delivery in both interhospital transport and primary care interventions. Efforts in these areas would not only have an economic impact through a significant reduction in costs, but could also improve long-term respiratory outcomes in paediatric patients.

The median age of paediatric patients with AB managed by OHUC teams in the Community of Madrid increased temporarily following the end of the lockdown imposed due to the COVID-19 pandemic, which was probably associated with the lack of exposure to the viruses that cause it. This also may explain why the incidence of bronchiolitis was highest in the season following the sixth wave of the pandemic.

The severity score was higher in neonatal patients. Epidemiological surveillance, the introduction of protocols and the implementation of an ongoing training programme for non-specialized health care staff involved in the transport of these patients could improve their management.

Fundación para la Investigación e Innovación Biomédica de Atención Primaria (FIIBAP, Foundation for Primary Care Research and Biomedical Innovation).

The authors have no conflicts of interest to disclose in relation to the study, of which there are no redundant or duplicated publications.