Saliva molecular testing bypassing RNA extraction is suitable for monitoring and diagnosing SARS-CoV-2 infection in children

• DOI: 10.1371/journal.pone.0268388
• Publication Date: 2022-06-15T17:52:41Z
• Authors: Marta Alenquer; Tiago Milheiro Silva; Onome Akpogheneta; Filipe Ferreira; Sílvia Vale-Costa; Mónica Medina-Lopes; Frederico Batista; Ana Margarida Garcia; Vasco M. Barreto; Cathy Paulino; João Costa; João Sobral; Maria Diniz-da-Costa; Susana Ladeiro; Rita Corte-Real; José Delgado Alves; Ricardo B. Leite; Jocelyne Demengeot; Maria João Rocha ...; Maria João Amorim
• Keywords: Infectivity

Background Adults are being vaccinated against SARS-CoV-2 worldwide, but the longitudinal protection of these vaccines is uncertain, given ongoing appearance variants. Children remain largely unvaccinated and susceptible to infection, with studies reporting that they actively transmit virus even when asymptomatic, thus affecting community. Methods We investigated if saliva an effective sample for detecting RNA antibodies in children, associated viral levels infectivity. For that, we used a saliva-based RT-qPCR test, preceded or not by extraction, 85 children aged 10 years under, admitted hospital regardless COVID-19 symptomatology. Amongst these, 29 (63.0%) presented at least one symptom, 46 (54.1%) were positive 28 (32.9%) under age 1, mean (SD) was 3.8 (3.4) years. Saliva samples collected up 48 h after nasopharyngeal swab-RT-qPCR test. Results In sensitivity, specificity, accuracy saliva-RT-qPCR tests compared NP were, respectively, 84.8% (71.8%–92.4%), 100% (91.0%–100%), 91.8% (84.0%–96.6%) 81.8% (68.0%–90.5%), 90.4% (82.1%–95.0%) without extraction. Rescue infectious particles from limited CT values below 26. addition, found significant IgM responses swab negative other groups, indicating late infection onset (>7–10 days). Conclusions suitable type diagnosing including infants <1 year, bypassing extraction methods. Importantly, detected significantly above infectivity threshold several samples. Further investigation required correlate transmission.