WHotLAMP: A simple, inexpensive, and sensitive molecular test for the detection of SARS-CoV-2 in saliva.

David Chee Eng Ng ,Barbara Noro,Felix Fiederling,Jeanine D’Armiento,Merly C Vogt,Enrico Cannavo,Tanya Tabachnik,Darcy S Peterka,Ashok Litwin-Kumar,Ines Rodrigues-Vaz,Stylianos Kosmidis,Monica Goldklang,Kyle Stearns,Ana Pinharanda,Armen Enikolopov,Peter Andolfatto,Urvashi V Thopte ,Hani J Shayya ,Andrés Bendesky

doi:10.1371/journal.pone.0257464

Abstract

Despite the development of effective vaccines against SARS-CoV-2, epidemiological control of the virus is still challenging due to slow vaccine rollouts, incomplete vaccine protection to current and emerging variants, and unwillingness to get vaccinated. Therefore, frequent testing of individuals to identify early SARS-CoV-2 infections, contact-tracing and isolation strategies remain crucial to mitigate viral spread. Here, we describe WHotLAMP, a rapid molecular test to detect SARS-CoV-2 in saliva. WHotLAMP is simple to use, highly sensitive (~4 viral particles per microliter of saliva) and specific, as well as inexpensive, making it ideal for frequent screening. Moreover, WHotLAMP does not require toxic chemicals or specialized equipment and thus can be performed in point-of-care settings, and may also be adapted for resource-limited environments or home use. While applied here to SARS-CoV-2, WHotLAMP can be modified to detect other pathogens, making it adaptable for other diagnostic assays, including for use in future outbreaks.

Highlights

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus with high transmissibility that causes the Coronavirus Disease of 2019 (COVID-19) [1, 2]
WHotLAMP is inexpensive, highly sensitive and specific, making it ideal for frequent screening and detection of infectious individuals to limit the spread of SARS-CoV-2
We initially tested saliva spiked with naked SARS-CoV-2 control RNA and found that a short exposure of Whatman No 1 filter paper to saliva, followed by brief washes, could capture sufficient SARS-CoV2 control RNA to be detected in a loop-mediated isothermal amplification (LAMP) reaction with primers directed against SARS-CoV-2 (Fig 1A)

Summary

Introduction

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus with high transmissibility that causes the Coronavirus Disease of 2019 (COVID-19) [1, 2]. Unlike SARS-CoV-1, where infectiousness is mostly restricted to the symptomatic phase [3], ~50% of SARS-CoV-2 transmissions occur 1–2 days before symptom onset or through people who never develop symptoms [4,5,6]. Screening for symptoms is not enough to stop SARS-CoV-2 transmission [7].

Methods

Results

Conclusion