Antibody levels to SARS-CoV-2 spike protein in mothers and children from delivery to six months later.

INTRODUCTION: Pregnant women are vulnerable to severe acute respiratory syndrome coronavirus (SARS-CoV-2) infection. Neutralizing antibodies against the SARS-CoV-2 spike (S) protein protect from severe disease. This study analyzes the antibody titers to SARS-CoV-2 S protein in pregnant women and their newborns at delivery, and six months later. METHODS: We conducted a prospective study on pregnant women with confirmed SARS-CoV-2 infection and newborns. Antibody (IgG, IgM, and IgA) titers were determined using immunoassays in serum and milk samples. An angiotensin-converting enzyme 2 (ACE2) receptor-binding inhibition assay to the S protein was performed on the same serum and milk samples. RESULTS: At birth, antibodies to SARS-CoV-2 spike protein were detected in 81.9% of mothers' sera, 78.9% of cord blood samples, and 63.2% of milk samples. Symptomatic women had higher antibody titers (IgG, IgM, and IgA) than the asymptomatic ones (P < 0.05). At six months postpartum, IgG levels decreased drastically in children's serum (P < 0.001) but remained high in mothers' serum. Antibody titers correlated positively with its capacity to inhibit the ACE2-spike protein interaction at baseline in maternal sera (R2  = 0.203; P < 0.001), cord sera (R2  = 0.378; P < 0.001), and milk (R2  = 0.564; P < 0.001), and at six months in maternal sera (R2  = 0.600; P < 0.001). CONCLUSIONS: High antibody levels against SARS-CoV-2 spike protein were found in most pregnant women. Due to the efficient transfer of IgG to cord blood and high IgA titers in breast milk, neonates may be passively immunized to SARS-CoV-2 infection. Our findings could guide newborn management and maternal vaccination policies.

Comparison of pneumonia features in children caused by SARS-CoV-2 and other viral respiratory pathogens. (preprint)

Pneumonia is a frequent manifestation of COVID-19 in hospitalized children. Methods The study involved 80 hospitals in the SARS-CoV-2 Spanish Pediatric National Cohort. Participants were children <18 years, hospitalized with SARS-CoV-2 community-acquired pneumonia (CAP). We compared the clinical characteristics of SARS-CoV-2-associated CAP with CAP due to other viral etiologies from 2012 to 2019. Results In total, 151 children with SARS-CoV-2-associated CAP and 138 with other viral CAP included. Main clinical features of SARS-CoV-2-associated CAP were cough 117/151(77%), fever 115/151(76%) and dyspnea 63/151(46%); 22/151(15%) patients were admitted to a pediatric intensive care unit (PICU), and 5/151(3%) patients died. Lymphopenia was found in 63/147(43%) patients. Chest X-ray revealed condensation (64/151[42%]) and other infiltrates (87/151[58%]). Compared with CAP from other viral pathogens, COVID-19 patients were older (8 vs.1 year; odds ratio [OR] 1.42 [95% confidence interval, CI 1.23;1.42]), with lower CRP levels (23 vs.48 mg/L; OR 1 [95%CI 0.99;1]), less wheezing (17 vs.53%; OR 0.18 [95%CI 0.11;0.31]) and greater need of mechanical ventilation, MV (7 vs.0.7%, OR 10.8 [95%CI 1.3;85). Patients with non-SARS-CoV-2-associated CAP had a greater need for oxygen therapy (77 vs.44%, OR 0.24 [95%CI 0.14;0.40]). There were no differences in the use of CPAP or HVF or PICU admission between groups. Conclusion SARS-CoV-2-associated CAP in children presents differently to other virus-associated CAP: children are older and rarely have wheezing or high CRP levels; they need less oxygen but more CPAP or MV. However, several features overlap, and differentiating the etiology may be difficult. The overall prognosis is good.

The Spectrum of COVID-19 in Children in Spain (preprint)

Background: We aimed to identify the spectrum of disease in children with COVID-19, and the risk factors for admission in paediatric intensive care units (PICUs). Methods: : We conducted a multicentre, prospective study of children with SARS-CoV-2 infection in 76 Spanish hospitals. We included children with COVID-19 or multi-inflammatory syndrome (MIS-C) younger than 18 years old, attended during the first year of the pandemic. Results: We enrolled 1 200 children. A total of 666 (55.5%) were hospitalized, and 123 (18.4%) required admission to PICU. Most frequent major clinical syndromes in the cohort were: mild syndrome (including upper respiratory tract infection and flu-like syndrome, skin or mucosae problems and asymptomatic), 44.8%; bronchopulmonary syndrome (including pneumonia, bronchitis and asthma flare), 18.5%; fever without a source, 16.2%; MIS-C, 10.6%; and gastrointestinal syndrome, 10%. In hospitalized children, the proportions were: 28.5%, 25.7%, 16.5%, 19.1% and 10.2%, respectively. Risk factors associated with PICU admission were MIS-C (odds ratio [OR]: 37.5,95% CI 22.7 to 57.8), moderate or severe liver disease (OR: 9,95% CI 1.6 to 47.6), chronic cardiac disease (OR: 4.8,95% CI 1.8 to 13) and asthma or recurrent wheezing (OR: 2.8,95% CI 1.3 to 5.8). However, asthmatic children were admitted into the PICU due to MIS-C or pneumonia, not due to asthma flare. Conclusion: Hospitalized children with COVID-19 usually present as one of five major clinical phenotypes of decreasing severity. Risk factors for PICU include MIS-C, elevation of inflammation biomarkers, asthma, moderate or severe liver disease and cardiac disease.