Introduction
In 2020, the world was shocked by the pandemic of coronavirus disease 2019 (COVID-19) caused by the SARS-CoV-2 virus [
1]. During the first 4 months of the year, transmission rates in Europe were of such a significant magnitude that several governments were forced to impose harsh lockdowns [
2]. In the Netherlands, the first COVID-19 case was diagnosed on the 27th of February, and the government imposed a limited lockdown on the 23rd of March due to spiraling infection numbers. This lockdown led to closure of schools, daycares, and catering industry until the 11th of May and the 1st of June, respectively [
3].
Lockdowns are serious interventions and are not expected to only have a specific effect on COVID-19 transmission but on all transmissible infectious diseases. This has been reported in similar situations in the past [
4]. This effect may be especially pronounced in the field of pediatrics, as 28% of diagnoses in pediatric emergency departments (EDs) are attributed to infectious disease [
5]. As expected, a decrease in the total numbers of pediatric admissions and visits to the emergency department (ED) has followed lockdowns worldwide [
6‐
8]. However, it is unclear whether this reduction is solely due to a decrease in transmissible infections or also by behavioral changes around healthcare utilization. For example, there have been numerous reported examples of avoidance of care due to fear of a hospital environment, which is potentially disastrous [
9‐
11].
Although the overall reduction in pediatric patients seeking care has been widely reported, stratification of specific disease groups has not been performed. If avoidance of care is a significant factor, one would expect a similar reduction in admissions and ED visits due to noninfectious disease compared to visits for transmissible infectious disease. Furthermore, lockdown as intervention allows for a unique opportunity to investigate the incidence of diagnoses that are assumed, but not definitively proven, to be related to or luxated by transmissible infections.
The aim of this study was to quantify the impact of the Dutch lockdown on pediatric clinical care in the Netherlands, to assess whether the impact can be attributed solely to a decrease in transmissible infections, and to critically review and summarize the international literature regarding the effect of lockdown on pediatric clinical care.
Discussion
Emergency department visits and hospital admissions were impressively decreased during COVID-19 lockdowns, especially for children with communicable infections. When determining the reason for the observed effects, we expect that three separate caused have played some part in the observed reduction in clinical visits.
First, the closure of school and daycares led to an immediate and dramatic decrease in contacts between children and, as a result, in transmissible infections, which are the cause of a large proportion of pediatric healthcare visits. The current study supports this hypothesis, as the largest observed reduction in ED visits and admissions was found for transmissible infections and infection-related diagnoses. If this reduction could not be attributed to this effect, a reduction of similar size would be expected in the other categories as well. This factor could be considered a positive consequence of a lockdown, which may have led to a decrease in morbidity and healthcare costs. The number of children visiting the ED because of a respiratory illness was reduced more compared to other pediatric diagnoses in other countries as well. Hartnett et al. reported that the largest declines in the number of ED visits were seen in children aged ≤10 years for respiratory symptoms (78%), viral infections (79%), influenza (97%), and otitis (85%) [
39]. A large time series analysis in France also reported a 70% reduction for the common cold, otitis media, and gastro-enteritis. In this study, visits because of urinary tract infections (UTIs) were not affected, and UTI admissions even increased by 21%, which is in line with our findings [
40]. Furthermore, several Italian hospitals saw a decline of 60–96% for presentations because of fever and respiratory or other infections [
18‐
23]. Other countries reported a decrease in respiratory infections between 52 and 98% as well, and this reduction was generally larger than for other diagnosis groups [
8,
33,
36,
37,
41,
42], except for two studies in Spain, a country with a harsh lockdown [
13]. Here, the reduction in the number of ED visits because of respiratory symptoms was identical to the overall reduction in visits [
16,
35]. In addition to reduced ED visits, our data also showed a decrease in infection-related hospitalizations, which was also observed in Denmark [
43].
A second factor of influence could have been the fact that the pandemic led to an extreme demand on the healthcare sector and that clinical care in the hospital largely revolved around COVID-19 patients. Fear of SARS-CoV-2 infection and a desire to not raise demand on the healthcare sector even further may have caused parents to refrain from going to the hospital with their children, despite worsening symptoms [
44]. In that case, a reduction in noncommunicable infections and noninfectious diagnoses would be expected. Our data indicates a significant decrease in clinical care related to noninfectious diagnoses, although the reduction was less compared nontransmissible infections. Interestingly, the ratio between admissions and ED visits remained constant in 2020 compared to 2016–2019. If avoidance of care would lead to more children with high acuity illness due to delayed presentation to the ED, this ratio would be expected to rise compared to the previous years. The fact that this was not the case gives reassurance that the avoidance of care did not lead to adverse consequences on a large scale in the Netherlands. However, we did not take disease severity or length of stay into account in our analyses, and more than 50 anecdotal reports regarding collateral harm due to delayed presentation were reported in the Netherlands [
45]. However, several countries reported a higher admission/ED visit ratio, and studies that analyzed triage codes found that overall reasons for the ED visit were associated with a higher acuity of disease [
28,
41,
46]. Furthermore, there is ample international evidence that point to adverse consequences due to care avoidance. For example, although Dayal et al. reported a 75% reduction in the number of new diabetes cases during lockdown, the authors described three patients who have been diagnosed during lockdown and suffered from severe diabetic keto-acidosis, in which parents declared they delayed seeking care due to COVID-19 circumstances [
47].
Third, it is possible that parents and other caregivers experienced less pressure than usual to seek prompt clinical care for their children in the event of illness. During lockdown, working from home was mandatory and childcare was necessarily combined with professional activities. Additionally, reduced external feedback regarding health from schoolteachers, daycare workers, or grandparents could also lead to a reduced extrinsic motivation to visit the ED [
48]. Some evidence of this effect could be derived from the current analysis, since numbers of noninfectious diagnoses were also reduced. However, it is not possible to completely isolate this effect from the avoidance of care that is assumed to be a factor as well.
The dramatic decrease in transmissible infectious diseases leads to an opportunity to study the incidence of diagnoses that are assumed but not definitely proven to be caused by infections. While the base of circumstantial evidence to this effect is broad, the current analysis further adds to this. The relative reduction in assumed infection-related diagnoses was as large as the reduction for communicable infections. Our review of the literature found that similar reductions in pediatric healthcare utilization have been reported worldwide (Table
1). Besides general effects on the total volume of pediatric care, several studies reported on the effect of lockdown for individual diagnoses. For example, ED visits because of asthma decreased by 76–84% [
30,
39], and Tacquechel et al. reported a 87% decrease in daily outpatient visits due to asthma and an 84% decrease in hospital visits (ED and inpatient) [
49]. Shifts in the incidence of diagnoses in other specialties were also reported. For example, hospital admissions to a dermatology department in Poland reduced by 85% [
50]. Finally, it is important to note that the pandemic and the accompanying lockdowns may also exhibit negative effects on mental health. For example, a 25% increase in diagnoses related to mental health and a 104% increase in admissions due to anorexia nervosa have been reported [
51,
52]. On the other hand, a 27% reduction in mental health–related diagnoses as reason for ED visits was reported in Ireland [
36]. The reduction in healthcare utilization was comparable to many other countries, despite the limited lockdown imposed in the Netherlands.
Our study has several limitations. First, since noncommunicable infections were a relatively small percentage of total diagnoses and as a result, the effect of lockdown on this category was difficult to estimate. Second, data on the level of ED acuity, length of hospital admission, and ICU admissions could have provided additional insights but were not available. Furthermore, due to different electronic management systems in each hospital, data exports were conducted individually for each study center. Although the requested data was specific, this may have led to small numbers of diagnoses that have been missed.
Strengths of this study include the multicenter approach, which makes this one of the most comprehensive analyses to date, allowed for the use of a mixed effects model and for the precise estimation of the average effects of lockdown in the Netherlands. Furthermore, the stratification of diagnoses in four categories gives a better overview of the specific effects of lockdown on the propensity of parents and children to go to the hospital during lockdowns. Future analyses may replicate the current findings but should also focus on the acuity of the clinical presentations and the proportion of delayed diagnoses or treatment.
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