Background: Social distancing measures are used to reduce the spreading of COVID-19. The aim of this study was to assess the impact of local restrictions on the transmission of respiratory virus infections. Methods: we retrospectively analyzed the nasopharyngeal samples of all patients (0–18 years old) admitted with respiratory symptoms in a large Italian tertiary hospital during the last three seasons from 2018 to 2021. Results: A strong reduction in all viral respiratory infections was observed in the last season (2020–2021) compared to the two previous seasons (−79.69% and −80.66%, respectively). In particular, we found that during the epidemic period 2018–2019 and 2019–2020, the total number of Respiratory Syncytial Virus (RSV) cases was, respectively 726 and 689, while in the last season a total of five cases was detected. In the first months of 2018–2019 and 2019–2020, the total flu infections were 240 and 354, respectively, while in the last season we did not detect any influenza virus. As other viruses, the presence of Rhinovirus declined, but to a lesser extent: a total of 488 cases were assessed compared to the 1030 and 1165 cases of the two previous respective epidemic seasons. Conclusions: Public health interventions and distancing (including continuous use of face masks) settled to counter the pandemic spread of COVID-19 had a macroscopic impact on all respiratory virus transmission and related diseases, with a partial exception of Rhinovirus. The absence of viruses’ circulation could result in a lack of immunity and increased susceptibility to serious infections in the next seasons.

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.

(1) Background: Infections in pregnancy can lead to miscarriage, premature birth, infections in newborns, and developmental disabilities in babies. Infected infants, symptomatic at birth, can have long-term sequelae, and asymptomatic babies are also at increased risk of developing long-term sensorineural outcomes. Targeted therapy of the pregnant mother can reduce fetal and neonatal harm. (2) Aim of the study: To explore the association between symptoms and time of onset of long-term sequelae in infected children born from mothers who contracted an infection during pregnancy, by a long-term multidisciplinary follow-up. (3) Methods: For up to 2–4 years, we evaluated cognitive, motor, audiological, visual, and language outcomes in infants with symptomatic and asymptomatic congenital infections and in uninfected infants. (4) Results: 186 infants born from women who acquired Cytomegalovirus infection (n = 103), Toxoplasma infection (n = 50), and Syphilis (n = 33) during pregnancy were observed. Among them, 119 infants acquired the infection in utero. Infected infants, symptomatic at birth, obtained lower scores on the Cognitive and Motor Scale on Bayley-III compared to asymptomatic and uninfected infants (p = 0.026; p = 0.049). Many severe or moderate sequelae rose up within the first year of life. At 24 months, we observed sequelae in 24.6% (14/57) of infected children classified as asymptomatic at birth, compared to 68.6% (24/35) of symptomatic ones (χ² = 15.56; p < 0.001); (5) Conclusions: Infected babies symptomatic at birth have a worse prognosis than asymptomatic ones. Long-term sequelae may occur in infected children asymptomatic at birth after the first year of life. Multidisciplinary follow-up until 4–6 years of age should be performed in all infected children, regardless of the presence of symptoms at birth.

Influenza is a major public health issue worldwide. It is characterized by episodes of infection that involve hundreds of millions of people each year. Since that in the seasons 2010–2011 and 2011–2012 the circulation of FLUB was decreasing we evaluated the clinical presentation, demographic characteristics, admitting department, and length of stay in children who contracted influenza admitted to Bambino Gesù Children’s Hospital, during the 2012–2013 influenza season, with the aim to establish if the recover of FLUB was associated to a clinical worsening, in comparison with those due to FLUA. A total of 133 respiratory specimens, collected from patients with symptoms of respiratory tract infections, positive for the Influenza A and B viruses (FLUA and B) were subtyped. Comparisons between the FLUA and FLUB groups were performed with the one-way ANOVA for continuous parametric variables, the Mann-Whitney test for non-parametric variables, or the Chi-Square test or Fisher’s exact test (if cells <5) for categorical variables. 87.09 % of the FLUA isolates were the H1N1 subtype and 12.90 % were H3N2. Among the FLUB isolates, 91.54 % were the B/Yamagata/16/88 lineage and 8.45 % were the B/Victoria/02/87 lineage. The largest number of FLUA/H1N1 cases was observed in children less than 1 years old, while the B/Yamagata/16/88 lineage was most prevalent in children 3–6 years old. Fever was a common symptom for both FLUA and B affected patients. However, respiratory symptoms were more prevalent in patients affected by FLUA. The median length of stay in the hospital was 5 days for FLUA and 3 days for FLUB. The clinical features correlated to different Influenza viruses, and relevant subtypes, were evaluated concluding that the increasing of FLUB in the season 2012–2013 was without any dramatic change in clinical manifestation. Our findings suggest, finally, that a stronger commitment to managing patients affected by FLUA is required, as the disease is more severe than FLUB.

Viral co-infections are frequently observed among children, but whether specific viral interactions enhance or diminish the severity of respiratory disease is still controversial. This study aimed to investigate the type of viral mono- and co-infections by also evaluating viral correlations in 3525 respiratory samples from 3525 pediatric in/outpatients screened by the Allplex Respiratory Panel Assays and with a Severe Acute Respiratory Syndrome-COronaVirus 2 (SARS-CoV-2) test available. Overall, viral co-infections were detected in 37.8% of patients and were more frequently observed in specimens from children with lower respiratory tract infections compared to those with upper respiratory tract infections (47.1% vs. 36.0%, p = 0.003). SARS-CoV-2 and influenza A were more commonly detected in mono-infections, whereas human bocavirus showed the highest co-infection rate (87.8% in co-infection). After analyzing viral pairings using Spearman’s correlation test, it was noted that SARS-CoV-2 was negatively associated with all other respiratory viruses, whereas a markedly significant positive correlation (p < 0.001) was observed for five viral pairings (involving adenovirus/human bocavirus/human enterovirus/metapneumoviruses/rhinovirus). The correlation between co-infection and clinical outcome may be linked to the type of virus(es) involved in the co-infection rather than simple co-presence. Further studies dedicated to this important point are needed, since it has obvious implications from a diagnostic and clinical point of view.

Background The objective of this study is to test how certain signs and symptoms related to COVID-19 in children predict the positivity or negativity of the SARS-CoV-2 nasopharyngeal swab in children. Methods We review the data of children who were tested for SARS-CoV-2 for a suspected infection. We compared the clinical characteristics of the subjects who tested positive and negative, including the sensibility, positive and negative predictive value of different combination of signs and symptoms. Results Of all the suspected infected, 2596 tested negative (96.2%) and 103 tested positive (3.8%). The median age was 7.0 and 5.3 years for the positive and negative ones, respectively. The female to male ratio was ~1:1.3. Fever and respiratory symptoms were mostly reported. Most positive children had a prior exposure to SARS-CoV-2-infected subjects (59.2%). A total of 99.3% of patients without fever nor exposure to the virus proved negative to the SARS-CoV-2 test. Conclusions Our study suggests that a child without fever or contact with infected subjects is SARS-CoV-2 negative. If this were to be confirmed, many resources would be spared, with improved care of both COVID-19 and not COVID-19-affected children. Impact Key message: lack of fever and exposure to SARS-CoV-2-infected people highly predicts a negative results of the SARS-CoV-2 nasopharyngeal swab in the paediatric population. Added value to the current literature: this is the first article to prove this point. Impact: reduction of emergency department accesses of children with suspected SARS-CoV-2 infection; increased outpatient management of children with cough or other common respiratory symptoms of infancy; sparing of many human and material health resources.