Discussion
The aim of this study was to explore an organisational mode (the “school hot spot”) for SARS-CoV-2 testing based on the spontaneous presentation of paediatric patients by analysing the results of tests for SARS-CoV-2 carried out in the HS and comparing these results with SARS-CoV-2 tests performed in other paediatric hospital settings.
We found that the age group from 6 to 10 years attended school more in presence than older children (Ordinance n. 112, 20/10/2020)24 and, therefore, may have more chances of contagion and consequently may be more likely to be tested25. In addition, we found that sex was not associated with a higher probability of being tested in paediatric population, as reported in the literature25. In our sample, the swabs tested positive more frequently among children in the age group between 11 and 13 years. This might be partially explained by the fact that, in Italy, these group of children attended face to face school more than older children24 and are more likely to be swabbed26,27.
Compared with other settings, the HS was probably frequented more by children attending face-to-face learning compared with older ones. This could be due to the fact that face-to-face learning requires more frequent testing because the probability of having contact with positive people is higher. In literature, it is known that face-to-face learning increases the risk of contagion in children27.
We found a greater likelihood of testing positive in patients who swabbed at the HS compared with other settings. Indeed, the HS was aimed at patients with COVID-19 symptoms or with a history of close contact with a positive COVID-19 case, while the other settings had a different target population. In the emergency department, the only patients who were not tested were those who had a short outpatient visit and had no history of close contact with COVID-19 patients. In DH service, only patients who had a negative history for COVID-19 symptoms or contact with COVID-19 patients were tested, while, if the medical service was deferrable, patients with a history of COVID-19 were postponed. For this reason, in emergency department and DH, the prevalence of positive swabs was lower. Last, swabs performed in the hospital wards reported a greater probability of being positive than the DH service because they also include swabs performed in the COVID-19 ward of the paediatric hospital. Thus, we can hypothesize that the HS organizational model has been used in an appropriate manner because the probability that a COVID-19 positive patient was swabbed at the HS was higher compared with other examined settings, suggesting that patients and their families are able to understand when the swab is needed without asking a doctor or they are properly addressed by their GP or paediatrician.
Moreover, the multivariable models revealed other remarkable associations. First, in agreement with the literature28, our study found that new-borns are more likely to become infected than other paediatric patients. Then, we found that adolescents in the 11 to 13 age group had higher probability to test positive than patients in the 14 to 19 age group. A possible explanation for this could be that this age group attended face-to-face school more frequently and, consequently, was more exposed to the infection and was tested more27,29,30. Surprisingly, children aged between 3 months and 2 years and children aged between 3 years and 5 years had lower probability to test positive than adolescents (14-19 years age group). Although this age group went to school for more time in presence than adolescents, COVID-19 cases are less easily identifiable because young children tend to have milder symptoms as reported in literature11.
Understandably, children who received RADT were less likely to test positive. Indeed, this test was performed to patients only in the emergency department in case of a large influx of patients or when there was no time to wait for the result of the NAAT swab for the patient’s emergency conditions.
Finally, a higher mean of pooled Rt in the 14 days preceding the swab was associated with higher probability of being positive to the swab. In line with this, as shown in Figure 1, also the proportion of swabs that tested positive and the number of total swabs performed in the HS followed the trend of the SARS-CoV-2 pandemic. As it is easy to understand, when the viral circulation is greater the probability of being symptomatic or having had contacts may also increase.
The present paper had some strengths and limitations that should be acknowledged. To the best of our knowledge, this was the first study that described a direct access testing modality for paediatric patients attending school. Furthermore, we analysed a large sample of paediatric patients spread over two waves of pandemics. However, the limitations were mainly related to the impossibility of correlating the patients’ history and symptoms with the result of the tests obtained. Moreover, we do not know how many patients contacted a doctor before presenting to the school hotspot and consequently we do not know the percentage of patients who presented spontaneously.
Nevertheless, the proposal of a new strategy of testing is urgent, especially among children and adolescents. As reported in the literature, there is limited evidence of the effectiveness of school closures in containing the pandemic and, given the important health implications of school closures on young people’s lives, it is important to implement preventive measures in order to reduce COVID-19 transmission and keep schools open11. Indeed, it is essential to test symptomatic cases and contact tracing should be initiated promptly following identification of a confirmed case in order to isolate positive patients31. This is even more important with the spread of the Delta variant (declared a Variant of Concern in May 2021).32 The Delta variant is the dominant strain, characterized by a higher transmission rate.33 Children are not vaccinated or are under-vaccinated and therefore there is an increasing number of SARS-CoV-2 cases reported.34 Moreover, with the increasing number of infections, also cases of hospitalization among children and adolescents can increase.34 Thus, increasing testing capacity appears necessary and the possibility of undergoing a swab for SARS-CoV-2 in direct access mode, as in our HS, could be implemented to carry out as many tests as possible35. Indeed, exploring this testing modality, we found a high rate of paediatric patients positive at the HS compared with other hospital testing settings (emergency department, DH and Hospital wards).
The free presentation mode can be effective in identifying a high number of positive patients but also to be able to exclude the diagnosis of COVID-19 in many paediatric patients in order to allow a quick return to school36. Particularly, this testing system should be aimed at older children because they are more likely to be infected in school settings36,37. In a context of pandemic emergency and limited medical personnel, this testing modality saves doctors who, instead of carrying out the patient history before deciding whether to carry out the nasopharyngeal swab, can devote themselves to other clinical activities. In view of the restart of face-to-face learning activities, public health authorities should implement this testing modality in order to help reduce the spread of SARS-CoV-2 in school settings.