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1.
Front Immunol ; 13: 751705, 2022.
Article in English | MEDLINE | ID: covidwho-1686480

ABSTRACT

COVID-19 affects children to a lesser extent than adults but they can still get infected and transmit SARS-CoV-2 to their contacts. Field deployable non-invasive sensitive diagnostic techniques are needed to evaluate the infectivity dynamics of SARS-CoV-2 in pediatric populations and guide public health interventions, particularly if this population is not fully vaccinated. We evaluated the utility of high-throughput Luminex assays to quantify saliva IgM, IgA and IgG antibodies against five SARS-CoV-2 spike (S) and nucleocapsid (N) antigens in a contacts and infectivity longitudinal study in 122 individuals (52 children and 70 adults). We compared saliva versus serum/plasma samples in infected children and adults diagnosed by weekly RT-PCR over 35 days (n=62), and those who consistently tested negative over the same follow up period (n=60), in the Summer of 2020 in Barcelona, Spain. Saliva antibody levels in SARS-CoV-2 RT-PCR positive individuals were significantly higher than in negative individuals and correlated with those measured in sera/plasmas. Asymptomatic infected individuals had higher levels of anti-S IgG than symptomatic individuals, suggesting a protective anti-disease role for antibodies. Higher anti-S IgG and IgM levels in serum/plasma and saliva, respectively, in infected children compared to infected adults could also be related to stronger clinical immunity in them. Among infected children, males had higher levels of saliva IgG to N and RBD than females. Despite overall correlation, individual clustering analysis suggested that responses that may not be detected in blood could be patent in saliva, and vice versa. In conclusion, measurement of SARS-CoV-2-specific saliva antibodies should be considered as a complementary non-invasive assay to serum/plasma to determine COVID-19 prevalence and transmission in pediatric populations before and after vaccination campaigns.


Subject(s)
Antibodies, Viral/analysis , COVID-19 Serological Testing/methods , COVID-19/diagnosis , Immunoassay/methods , Saliva , Adult , Child , Female , Humans , Immunoglobulin A/analysis , Immunoglobulin G/analysis , Immunoglobulin M/analysis , Male , SARS-CoV-2 , Spain
2.
Clin Infect Dis ; 74(1): 66-73, 2022 01 07.
Article in English | MEDLINE | ID: covidwho-1633721

ABSTRACT

BACKGROUND: Understanding the role of children in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission is critical to guide decision-making for schools in the pandemic. We aimed to describe the transmission of SARS-CoV-2 among children and adult staff in summer schools. METHODS: During July 2020, we prospectively recruited children and adult staff attending summer schools in Barcelona who had SARS-CoV-2 infection. Primary SARS-CoV-2 infections were identified through (1) a surveillance program in 22 summer schools of 1905 participants, involving weekly saliva sampling for SARS-CoV-2 reverse-transcription polymerase chain reaction (RT-PCR) during 2-5 weeks; and (2) cases identified through the Catalonian Health Surveillance System of children diagnosed with SARS-CoV-2 infection by nasopharyngeal RT-PCR. All centers followed prevention protocols: bubble groups, handwashing, face masks, and conducting activities mostly outdoors. Contacts of a primary case within the same bubble were evaluated by nasopharyngeal RT-PCR. Secondary attack rates and the effective reproduction number in summer schools (Re*) were calculated. RESULTS: Among the >2000 repeatedly screened participants, 30 children and 9 adults were identified as primary cases. A total of 253 close contacts of these primary cases were studied (median, 9 [interquartile range, 5-10] for each primary case), among which 12 new cases (4.7%) were positive for SARS-CoV-2. The Re* was 0.3, whereas the contemporary rate in the general population from the same areas in Barcelona was 1.9. CONCLUSIONS: The transmission rate of SARS-CoV-2 infection among children attending school-like facilities under strict prevention measures was lower than that reported for the general population. This suggests that under preventive measures schools are unlikely amplifiers of SARS-CoV-2 transmission, supporting current recommendations for school opening.


Subject(s)
COVID-19 , Adult , Child , Humans , Pandemics , SARS-CoV-2 , Schools , Spain/epidemiology
3.
BMC Med ; 19(1): 309, 2021 11 23.
Article in English | MEDLINE | ID: covidwho-1528684

ABSTRACT

BACKGROUND: Surveillance tools to estimate viral transmission dynamics in young populations are essential to guide recommendations for school opening and management during viral epidemics. Ideally, sensitive techniques are required to detect low viral load exposures among asymptomatic children. We aimed to estimate SARS-CoV-2 infection rates in children and adult populations in a school-like environment during the initial COVID-19 pandemic waves using an antibody-based field-deployable and non-invasive approach. METHODS: Saliva antibody conversion defined as ≥ 4-fold increase in IgM, IgA, and/or IgG levels to five SARS-CoV-2 antigens including spike and nucleocapsid constructs was evaluated in 1509 children and 396 adults by high-throughput Luminex assays in samples collected weekly in 22 summer schools and 2 pre-schools in 27 venues in Barcelona, Spain, from June 29th to July 31st, 2020. RESULTS: Saliva antibody conversion between two visits over a 5-week period was 3.22% (49/1518) or 2.36% if accounting for potentially cross-reactive antibodies, six times higher than the cumulative infection rate (0.53%) assessed by weekly saliva RT-PCR screening. IgG conversion was higher in adults (2.94%, 11/374) than children (1.31%, 15/1144) (p=0.035), IgG and IgA levels moderately increased with age, and antibodies were higher in females. Most antibody converters increased both IgG and IgA antibodies but some augmented either IgG or IgA, with a faster decay over time for IgA than IgG. Nucleocapsid rather than spike was the main antigen target. Anti-spike antibodies were significantly higher in individuals not reporting symptoms than symptomatic individuals, suggesting a protective role against COVID-19. CONCLUSION: Saliva antibody profiling including three isotypes and multiplexing antigens is a useful and user-friendlier tool for screening pediatric populations to detect low viral load exposures among children, particularly while they are not vaccinated and vulnerable to highly contagious variants, and to recommend public health policies during pandemics.


Subject(s)
COVID-19 , SARS-CoV-2 , Adult , Antibodies, Viral , Child , Child, Preschool , Female , Humans , Immunoglobulin G , Pandemics , Saliva , Schools , Spain/epidemiology , Spike Glycoprotein, Coronavirus
4.
J Infect ; 82(3): 414-451, 2021 03.
Article in English | MEDLINE | ID: covidwho-1386002

ABSTRACT

OBJECTIVE: This study describes the characteristics of children requiring admission with an acute lower-respiratory disease (ALRD) during the SARS-CoV-2 pandemics. METHODS: Epidemiological, clinical, and microbiological data from patients with ALRD (pneumonia, bronchiolitis, bronchospasm) admitted to a reference paediatric hospital in Spain during the pandemic peak (week 11-20/2020) were prospectively analysed. RESULTS: 110 patients were included. 7 were SARS-CoV-2(+) and they were older in comparison to SARS-CoV-2(-). Among SARS-CoV-2(+) patients, pneumonia was the main clinical diagnosis (6/7) and bronchospasm was absent. Only 1 of 29 infants diagnosed with bronchiolitis was SARS-CoV-2(+). Lower values of leucocytes, lymphocytes, neutrophils, and platelets and higher values of creatinine were found in SARS-CoV-2(+). Human-rhinovirus/enterovirus was the main detection (11/32). There were not differences in PICU admission rates between SARS-CoV-2(+) and (-). CONCLUSIONS: Most of the ALRD episodes identified during the pandemics were not related to SARS-CoV-2 infection. SARS-CoV-2 was mainly found causing pneumonia in older children.


Subject(s)
COVID-19 , SARS-CoV-2 , Child , Hospitalization , Humans , Infant , Pandemics , Spain/epidemiology
5.
J Clin Invest ; 131(6)2021 03 15.
Article in English | MEDLINE | ID: covidwho-1133407

ABSTRACT

Multisystem inflammatory syndrome associated with the SARS-CoV-2 pandemic has recently been described in children (MIS-C), partially overlapping with Kawasaki disease (KD). We hypothesized that (a) MIS-C and prepandemic KD cytokine profiles may be unique and justify the clinical differences observed, and (b) SARS-CoV-2-specific immune complexes (ICs) may explain the immunopathology of MIS-C. Seventy-four children were included: 14 with MIS-C, 9 patients positive for SARS-CoV-2 by PCR without MIS-C (COVID), 14 with prepandemic KD, and 37 healthy controls (HCs). Thirty-four circulating cytokines were quantified in pretreatment serum or plasma samples and the presence of circulating SARS-CoV-2 ICs was evaluated in MIS-C patients. Compared with HCs, the MIS-C and KD groups showed most cytokines to be significantly elevated, with IFN-γ-induced response markers (including IFN-γ, IL-18, and IP-10) and inflammatory monocyte activation markers (including MCP-1, IL-1α, and IL-1RA) being the main triggers of inflammation. In linear discriminant analysis, MIS-C and KD profiles overlapped; however, a subgroup of MIS-C patients (MIS-Cplus) differentiated from the remaining MIS-C patients in IFN-γ, IL-18, GM-CSF, RANTES, IP-10, IL-1α, and SDF-1 and incipient signs of macrophage activation syndrome. Circulating SARS-CoV-2 ICs were not detected in MIS-C patients. Our findings suggest a major role for IFN-γ in the pathogenesis of MIS-C, which may be relevant for therapeutic management.


Subject(s)
COVID-19/etiology , Cytokines/blood , Mucocutaneous Lymph Node Syndrome/etiology , Systemic Inflammatory Response Syndrome/etiology , Adolescent , Antibodies, Viral/blood , Antigen-Antibody Complex/blood , Antigens, Viral/blood , COVID-19/immunology , COVID-19/virology , Case-Control Studies , Child , Child, Preschool , Cohort Studies , Cross-Sectional Studies , Female , Humans , Infant , Interferon-gamma/blood , Male , Models, Immunological , Mucocutaneous Lymph Node Syndrome/immunology , Pandemics , SARS-CoV-2/genetics , SARS-CoV-2/immunology , Systemic Inflammatory Response Syndrome/immunology , Systemic Inflammatory Response Syndrome/virology
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