Severe viral respiratory infections in the pre-COVID era: A 5-year experience in two pediatric intensive care units in Italy.

BACKGROUND: Viral respiratory infections are one of the main causes of hospitalization in children. Even if mortality rate is low, 2% to 3% of the hospitalized children need mechanical ventilation. Risk factors for admission to the pediatric intensive care unit (PICU) are well known, while few studies have described risk factors for invasive ventilator support and prolonged hospitalization. METHODS: A retrospective study including all patients aged between 2 and 18 months with a confirmed viral respiratory infection, requiring admission to PICU from September to March between 2015 and 2019, was conducted at Bambino Gesù Children's Hospital in Rome, Italy. RESULTS: One hundred ninety patients were enrolled, with a median age of 2.7 months; 32.1% had at least one comorbidity, mainly prematurity. The most frequent isolated viruses were RSV-B, rhinovirus, and RSV-A; 38.4% needed mechanical ventilation. This subgroup of patients had lower median birth weight compared with patients not requiring mechanical ventilation (2800 g vs. 3180 g, p = 0.02); moreover, comorbidities were present in 43.8% of intubated patients and in 24.8% of patients treated with non-invasive ventilation (p = 0.006). Viral coinfection did not result to be a risk factor for mechanical support, while virus-bacteria coinfection was significantly associated with mechanical ventilation (p < 0.001). Similar risk factors were identified for prolonged hospitalization. CONCLUSIONS: Early identification of patients who could have a sudden respiratory deterioration and need of mechanical ventilation is crucial to reduce complications due to orotracheal intubation and prolonged hospitalization in PICU. Further studies are needed to define high-risk group of patients and to design targeted interventions.

No evidence of SARS-CoV-2 in hospitalized patients with severe acute respiratory syndrome in five Italian hospitals from 1st November 2019 to 29th February 2020.

BACKGROUND: On 9th January 2020, China CDC reported a novel coronavirus (later named SARS-CoV-2) as the causative agent of the coronavirus disease 2019 (COVID-19). Identifying the first appearance of virus is of epidemiological importance to tracking and mapping the spread of SARS-CoV-2 in a country. We therefore conducted a retrospective observational study to detect SARS-CoV-2 in oropharyngeal samples collected from hospitalized patients with a Severe Acute Respiratory Infection (SARI) enrolled in the DRIVE (Development of Robust and Innovative Vaccine Effectiveness) study in five Italian hospitals (CIRI-IT BIVE hospitals network) (1st November 2019 - 29th February 2020). OBJECTIVES: To acquire new information on the real trend in SARS-CoV-2 infection during pandemic phase I and to determine the possible early appearance of the virus in Italy. MATERIALS AND METHODS: Samples were tested for influenza [RT-PCR assay (A/H1N1, A/H3N2, B/Yam, B/Vic)] in accordance with the DRIVE study protocol. Subsequently, swabs underwent molecular testing for SARS-COV-2. [one-step real-time multiplex retro-transcription (RT) PCR]. RESULTS: In the 1683 samples collected, no evidence of SARS-CoV-2 was found. Moreover, 28.3% (477/1683) of swabs were positive for influenza viruses, the majority being type A (358 vs 119 type B). A/H3N2 was predominant among influenza A viruses (55%); among influenza B viruses, B/Victoria was prevalent. The highest influenza incidence rate was reported in patients aged 0-17 years (40.3%) followed by those aged 18-64 years (24.4%) and ≥65 years (14.8%). CONCLUSIONS: In Italy, some studies have shown the early circulation of SARS-CoV-2 in northern regions, those most severely affected during phase I of the pandemic. In central and southern regions, by contrast no early circulation of the virus was registered. These results are in line with ours. These findings highlight the need to continue to carry out retrospective studies, in order to understand the epidemiology of the novel coronavirus, to better identify the clinical characteristics of COVID-19 in comparison with other acute respiratory illnesses (ARI), and to evaluate the real burden of COVID-19 on the healthcare system.

Highly Specific Memory B Cells Generation after the 2nd Dose of BNT162b2 Vaccine Compensate for the Decline of Serum Antibodies and Absence of Mucosal IgA.

Specific memory B cells and antibodies are a reliable read-out of vaccine efficacy. We analysed these biomarkers after one and two doses of BNT162b2 vaccine. The second dose significantly increases the level of highly specific memory B cells and antibodies. Two months after the second dose, specific antibody levels decline, but highly specific memory B cells continue to increase, thus predicting a sustained protection from COVID-19. We show that although mucosal IgA is not induced by the vaccination, memory B cells migrate in response to inflammation and secrete IgA at mucosal sites. We show that the first vaccine dose may lead to an insufficient number of highly specific memory B cells and low concentration of serum antibodies, thus leaving vaccinees without the immune robustness needed to ensure viral elimination and herd immunity. We also clarify that the reduction of serum antibodies does not diminish the force and duration of the immune protection induced by vaccination. The vaccine does not induce sterilizing immunity. Infection after vaccination may be caused by the lack of local preventive immunity because of the absence of mucosal IgA.

Sars-Cov2 Not Detected in a Pediatric Population With Acute Respiratory Infection in Primary Care in Central and Southern Italy From November 2019 to Early March 2020.

Background: In December 2019, a novel coronavirus named SARS-CoV-2 started circulating in China and this led to a major epidemic in Northern Italy between February and May 2020. Young children (aged <5 years) seem to be less affected by this coronavirus disease (COVID-19) compared to adults, although there is very little information on the circulation of this new virus among children in Italy. We retrospectively tested nasopharyngeal swabs for SARS-CoV-2 in samples collected in young children between November, 2019 and March, 2020 in the context of the RSV ComNet study. Methods: Two networks of primary care pediatricians in Lazio (Central Italy) and Puglia (Southern Italy) collected nasopharyngeal swabs from children, aged <5 years, presenting with symptoms for an acute respiratory infection (ARI). The RSV ComNet study is a multicenter study implemented to estimate the burden of RSV in young children (aged <5 years) in the community. Swabs were sent to a central reference laboratory and tested for 14 respiratory viruses through RT-PCR. All collected samples were retrospectively tested for SARS-CoV-2 using RT-PCR (Istituto Superiore di Sanità protocol). Results: A total of 293 children with ARI were identified in the two participating networks. The highest number of cases were recruited in weeks 51/2019 and 3/2020. The majority of patients (57%) came from the Lazio region. All of the 293 samples tested negative for SARS-Cov2. Rhinovirus was the most frequently detected virus (44%), followed by RSV (41%) and influenza viruses (14%). Conclusions: Our study shows that in Lazio (a region of intermediate SARS-COV-2 incidence) and Puglia (a region of low incidence), the SARS-Cov2 virus did not circulate in a sample of ARI pediatric cases consulting primary care pediatricians between November 2019 and March 2020.

Impact of the COVID-19 pandemic on the Emergency Department of a tertiary children's hospital.

BACKGROUND: Italy was the first country in Europe affected by COVID-19: the emergency started on February 20, 2020, culminating with national lockdown on March 11, which terminated on May 4, 2020. We describe how the pandemic affected Emergency Department (ED) accesses in a tertiary children's hospital, composed by two different pediatric centers, one located in Rome's city center and the second, Palidoro (regional COVID-19 center), in its surrounding metropolitan area, both in the Lazio region, analyzing the profile of admitted patients during the pandemic period in terms of their general characteristics (at presentation in the ED's) and urgent hospitalizations compared to prepandemic period. METHODS: The study compare the period between the 21st of February and the 30th of April 2020, covering the three phases of the national responses (this period will be referred to as the pandemic period) with the same period of 2019 (prepandemic period). The study analyzes the number of ED visits and urgent hospitalizations and their distribution according to selected characteristics. RESULTS: The reduction of ED visits was 56 and 62%, respectively in Rome and Palidoro centers. The higher relative decline was encountered for Diseases of Respiratory System, and for Diseases of the Nervous System and Sense Organs. A doubling of the relative frequency of hospitalizations was observed, going from 14.2 to 24.4% in Rome and from 6.4 to 10.3% in Palidoro. In terms of absolute daily numbers the decrease of urgent hospitalizations was less sharp than ED visits. For pathologies such as peritonitis, tumors or other possible life-treathening conditions we did not observe a significative increase due to delayed access. CONCLUSIONS: In the pandemic period there was a general reduction in the number of children referred to ED, such reduction was greater in low-acuity levels. The reduction for respiratory tract infections and other communicable diseases during school closure and the national lockdown must make us reflect on the possible impact that these conditions may have on the health system, in particular the ED, at the reopening of schools. The major problem remains the fear for possible diagnostic delays in life-threatening or crippling diseases; our study doesn't demonstrate an increase in number or significant delay in some serious conditions such as tumors, peritonitis, diabetic ketoacidosis, ileo-colic intussusception and testis/ovary torsion. A continuous, deep re-organizational process step by step of the ED is nececessary in the present and upcoming pandemic situation.

Facing SARS-CoV-2 Pandemic at a COVID-19 Regional Children's Hospital in Italy.

BACKGROUND: In Italy, the response to coronavirus disease 2019 (COVID-19) pandemic upgraded from social distancing on February 23, 2020, to national lockdown on March 11, 2020. We described how the pandemic affected a tertiary care children hospital with a dedicated COVID-19 regional center. METHODS: We analyzed the characteristics of emergency department (ED) visits, urgent hospitalizations and severe acute respiratory syndrome (SARS)-COV-2 reverse transcription-polymerase chain reaction testing, and COVID-19 patients across 3 response phases: before the first Italian case, before national lockdown and during lockdown. RESULTS: ED visits decreased from a daily mean of 239.1 before the first COVID-19 Italian case, to 79.6 during lockdown; urgent hospitalizations decreased from 30.6 to 21.2. As of April 20, 2020, 1970 persons were tested for SARS-CoV-2 reverse transcription-polymerase chain reaction and 2.6% were positive. Positive rates were 1.2% in the ED, 21.1% in the COVID center and 0.5% in other wards. The median age of COVID-19 patients (N = 33) was 6.7 years, 27% had coexisting conditions and 79% were related to family clusters. CONCLUSIONS: The pandemic strongly impacted on the use of hospital services, with a 67% reduction in ED visits and a 31% reduction in urgent hospitalizations. Separating the flows of suspected patients from all other patients, and centralization of suspected and confirmed cases in the COVID center enabled to control the risk of nosocomial SARS-CoV-2 transmission. Delay in hospital use for urgent care must be avoided, and clear communication on infection prevention and control must be provided to families. Further studies are needed to assess how the reduction in hospital use affected children healthcare needs during the pandemic.