# Saliva Is a Sensitive and Accessible Sample Both for SARS-CoV-2 Detection and for the Evaluation of Treatment Effectiveness in Follow-Up Studies

## TL;DR

This study shows saliva is as effective as nasal swabs for tracking SARS-CoV-2 and treatment responses, making it a practical alternative for follow-up studies.

## Contribution

The study demonstrates saliva's viability as an alternative sample for evaluating treatment effectiveness against SARS-CoV-2.

## Key findings

- Saliva and nasal swab samples showed good correlation in SARS-CoV-2 detection using real-time RT-PCR.
- Changes in cycle threshold levels were comparable in saliva and nasal swabs 7 and 30 days after treatment.
- Saliva is confirmed as a suitable matrix for in vivo follow-up studies of treatment effectiveness.

## Abstract

Despite emerging evidence indicating that molecular SARS-CoV-2 tests performed on saliva have diagnostic sensitivity and specificity comparable to those observed with nasopharyngeal swabs (NPSs), most in vivo follow-up studies on the efficacy of drugs against SARS-CoV-2 have been performed on NPSs, not considering saliva as a possible alternative matrix. For this reason, in this study, we used, in parallel, saliva and NPS samples for the detection of SARS-CoV-2 by real-time RT-PCR in patients receiving Tixagevimab/Cilgavimab, Nirmatrelvir/Ritonavir, or Sotrovimab as a treatment against SARS-CoV-2. Our results showed a good correlation between the NPS and saliva samples for each drug; moreover, comparable changes in the cycle threshold (Ct) levels in saliva and NPSs were observed both 7 days and 30 days after treatment, thus confirming that the saliva represents a good matrix for in vivo follow-up studies verifying the effectiveness of treatments against SARS-CoV-2.