Validation of a Methodology for the Detection of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Saliva by Real-Time RT-PCR (preprint)

Background: In January 2021, the city of Concepción in Chile suffered a second wave of COVID-19, while in early April 2021, all of Chile was facing the same situation. This generated the need to modify and validate a methodology for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in saliva, thereby expanding the capacity and versatility of testing.Methods: People who came to the health center in Concepción city to perform a test of real-time reverse transcription polymerase chain reaction (RT-PCR) from a nasopharyngeal swab (NPS) specimen were invited to participate in this study. A total of 131 participants agreed to sign an informed consent and provide saliva and NPS specimens to validate a methodology in terms of sensitivity, specificity, and statistical analysis of the Ct values from RT-PCR.Findings: Calculations pertaining to the 127 participants who were ultimately included in the analysis were the following: sensitivity at 94·34% (95% CI: 84·34%-98·82%) and specificity at 98·65% (95% CI: 92·70%-99·97%). The saliva specimen showed a very similar performance to NPS as demonstrated with the diagnostic parameters.Interpretations: This RT-PCR methodology from the saliva specimen is a highly sensitive and specific alternative as compared to the reference methodology, which uses an NPS specimen. This modified and validated methodology is intended for use in the in vitro diagnosis of SARS-CoV-2, which provides health authorities in Chile and local laboratories with a real alternative for RT-PCR from NPS.Funding Information: Health Public Institute of Chile.Declaration of Interests: All authors declare no competing interests.Ethics Approval Statement: The study had the authorization of the Scientific Ethics Committee of the Health Service of Concepción, Chile Number 20-01-02. Parents or legal guardians for volunteers under the age of 18 signed the informed consent.

C-Reactive protein and SOFA score as early predictors of critical care requirement in patients with COVID-19 pneumonia in Spain. (preprint)

Background: Some patients infected by SARS-CoV-2 in the recent pandemic have required critical care, becoming one of the main limitations of the health systems. Our objective has been to identify potential markers at admission predicting the need for critical care in patients with COVID-19 pneumonia Methods: We retrospectively collected and analyzed data from electronic medical records of patients with laboratory-confirmed SARS-CoV-19 infection by real-time RT-PCR. A comparison was made between patients staying in the hospitalization ward with those who required critical care. Univariable and multivariable logistic regression methods were used to identify risk factors predicting critical care need Findings: Between March 15 and April 15, 2020, 150 patients under the age of 75 were selected (all with laboratory confirmed SARS-CoV-19 infection), 75 patients requiring intensive care assistance and 75 remaining the regular hospitalization ward. Most patients requiring critical care were males, 76% compared with 60% in the non-critical care group (p<0,05). Multivariable regression showed increasing odds of in-hospital critical care associated with increased C-reactive protein (CRP) (odds ratio 1,052 (1,009-1,101); p=0,0043) and higher Sequential Organ Failure Assessment (SOFA) score (1,968 (1,389-2,590) p<0,0001) both at the time of hospital admission. The AUC-ROC for the combined model was 0,83 (0,76-0,90) (vs AUC-ROC SOFA p<0,05) Interpretation: Patients COVID-19 positive presenting at admission with high SOFA score [≥]2 combined with CRP [≥] 9,1 mg/mL could help clinicians to identify them as a group that will more likely require critical care so further actions might be implemented to improve their prognosis