TY - JOUR
T1 - Saliva molecular testing bypassing RNA extraction is suitable for monitoring and diagnosing SARS-CoV-2 infection in children
AU - Alenquer, Marta
AU - Silva, Tiago Milheiro
AU - Akpogheneta, Onome
AU - Ferreira, Filipe
AU - Vale-Costa, Sílvia
AU - Medina-Lopes, Mónica
AU - Batista, Frederico
AU - Garcia, Ana Margarida
AU - Barreto, Vasco M.
AU - Paulino, Cathy
AU - Costa, João
AU - Sobral, João
AU - Diniz-Da-Costa, Maria
AU - Ladeiro, Susana
AU - Corte-Real, Rita
AU - Alves, José Delgado
AU - Leite, Ricardo B.
AU - Demengeot, Jocelyne
AU - Brito, Maria João Rocha
AU - Amorim, Maria João
N1 - Funding Information:
This work was funded by the Fundação para a Ciência and Tecnologia (FCT, Portugal) under RESEARCH4COVID 19 call with reference 283_596885654 and co-funded by ANI under INOV4COVID (Funding to V.M.B.). M.J.A. is funded by the FCT (CEECIND/02373/2020). M.A. is funded by a Junior Researcher working contract from FCT and Instituto Gulbenkian de Ciência (IGC, Portugal). This work benefited from COVID19 emergency funds 2020 from Calouste Gulbenkian Foundation and from Oeiras city council. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. We would like to thank the technical support of IGC’s Advanced Imaging Facility (AIF-UIC).
Publisher Copyright:
© 2022 Alenquer et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
PY - 2022/6
Y1 - 2022/6
N2 - Background Adults are being vaccinated against SARS-CoV-2 worldwide, but the longitudinal protection of these vaccines is uncertain, given the ongoing appearance of SARS-CoV-2 variants. Children remain largely unvaccinated and are susceptible to infection, with studies reporting that they actively transmit the virus even when asymptomatic, thus affecting the community. Methods We investigated if saliva is an effective sample for detecting SARS-CoV-2 RNA and antibodies in children, and associated viral RNA levels to infectivity. For that, we used a saliva-based SARS-CoV-2 RT-qPCR test, preceded or not by RNA extraction, in 85 children aged 10 years and under, admitted to the hospital regardless of COVID-19 symptomatology. Amongst these, 29 (63.0%) presented at least one COVID-19 symptom, 46 (54.1%) were positive for SARS-CoV-2 infection, 28 (32.9%) were under the age of 1, and the mean (SD) age was 3.8 (3.4) years. Saliva samples were collected up to 48 h after a nasopharyngeal swab-RT-qPCR test. Results In children aged 10 years and under, the sensitivity, specificity, and accuracy of saliva-RT-qPCR tests compared to NP swab-RT-qPCR were, respectively, 84.8% (71.8%–92.4%), 100% (91.0%–100%), and 91.8% (84.0%–96.6%) with RNA extraction, and 81.8% (68.0%–90.5%), 100% (91.0%–100%), and 90.4% (82.1%–95.0%) without RNA extraction. Rescue of infectious particles from saliva was limited to CT values below 26. In addition, we found significant IgM positive responses to SARS-CoV-2 in children positive for SARS-CoV-2 by NP swab and negative by saliva compared to other groups, indicating late infection onset (>7–10 days). Conclusions Saliva is a suitable sample type for diagnosing children aged 10 years and under, including infants aged <1 year, even bypassing RNA extraction methods. Importantly, the detected viral RNA levels were significantly above the infectivity threshold in several samples. Further investigation is required to correlate SARS-CoV-2 RNA levels to viral transmission.
AB - Background Adults are being vaccinated against SARS-CoV-2 worldwide, but the longitudinal protection of these vaccines is uncertain, given the ongoing appearance of SARS-CoV-2 variants. Children remain largely unvaccinated and are susceptible to infection, with studies reporting that they actively transmit the virus even when asymptomatic, thus affecting the community. Methods We investigated if saliva is an effective sample for detecting SARS-CoV-2 RNA and antibodies in children, and associated viral RNA levels to infectivity. For that, we used a saliva-based SARS-CoV-2 RT-qPCR test, preceded or not by RNA extraction, in 85 children aged 10 years and under, admitted to the hospital regardless of COVID-19 symptomatology. Amongst these, 29 (63.0%) presented at least one COVID-19 symptom, 46 (54.1%) were positive for SARS-CoV-2 infection, 28 (32.9%) were under the age of 1, and the mean (SD) age was 3.8 (3.4) years. Saliva samples were collected up to 48 h after a nasopharyngeal swab-RT-qPCR test. Results In children aged 10 years and under, the sensitivity, specificity, and accuracy of saliva-RT-qPCR tests compared to NP swab-RT-qPCR were, respectively, 84.8% (71.8%–92.4%), 100% (91.0%–100%), and 91.8% (84.0%–96.6%) with RNA extraction, and 81.8% (68.0%–90.5%), 100% (91.0%–100%), and 90.4% (82.1%–95.0%) without RNA extraction. Rescue of infectious particles from saliva was limited to CT values below 26. In addition, we found significant IgM positive responses to SARS-CoV-2 in children positive for SARS-CoV-2 by NP swab and negative by saliva compared to other groups, indicating late infection onset (>7–10 days). Conclusions Saliva is a suitable sample type for diagnosing children aged 10 years and under, including infants aged <1 year, even bypassing RNA extraction methods. Importantly, the detected viral RNA levels were significantly above the infectivity threshold in several samples. Further investigation is required to correlate SARS-CoV-2 RNA levels to viral transmission.
UR - http://www.scopus.com/inward/record.url?scp=85132082722&partnerID=8YFLogxK
U2 - 10.1371/journal.pone.0268388
DO - 10.1371/journal.pone.0268388
M3 - Article
C2 - 35704567
AN - SCOPUS:85132082722
SN - 1932-6203
VL - 17
JO - PLoS one
JF - PLoS one
IS - 6 June
M1 - e0268388
ER -