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

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.

Extraction Procedures for Hair Forensic Toxicological Analysis: A Mini-Review.

In forensic toxicology, drugs of abuse are routinely analyzed due to legal statute in medical or legal investigation, such as death cases, poisoning cases, and drug misuse, determining potential exposure to controlled substances. Despite the widespread use of blood and urine as matrices for forensic toxicological analysis, the use of hair samples has grown as the limitations associated with this matrix are overcome and new areas of application emerge. Hair provides several advantages over urine and blood, such as the easiness of sample collection and the ability to provide a retrospective analysis of drug consumption. Drug analysis in hair is following a path where less amount of sample has been needed to detect drugs of abuse. Improvement in sample preparation methods and lowering detection limits in instrumental analysis is providing forensic scientists with the tools to use drug analysis with hair as a routine approach in the forensic laboratory. Actually, besides the chronological exposition to a drug, hair may provide information about the day a chemical was used. This should become part of the standard information sent by forensic scientists to criminal investigators and courts. The aim of this review is to summon the extraction procedures used to perform forensic toxicological analysis in hair as well as the major advances in this field once a sample preparation step is critical and takes up most of the total analysis time.