SARS-CoV-2 RNA Persistence in Naso-Pharyngeal Swabs.

Maria Luisa Danzetta,Laura Amato,Daniela Morelli,Ottavio Portanti,Federica Monaco,Paolo Calistri,Claudia Casaccia,Giacomo Migliorati,Giovanni Savini,Lilia Testa,Ilaria Puglia,Francesca Cito,Nicola D’Alterio,Annapia Di Gennaro,Maria Teresa Mercante,Alessandra Di Giuseppe,Alessio Lorusso

doi:10.3390/microorganisms8081124

Abstract

Since February 2020, Italy has been seriously affected by the SARS-CoV-2 pandemic. To support the National Health Care system, naso-pharyngeal/oropharyngeal swabs collected from suspected cases of Teramo province, Abruzzo region, are tested at Istituto Zooprofilattico Sperimentale dell’Abruzzo e del Molise G. Caporale, for the presence of SARS-CoV-2 RNA. Out of 12,446 tested individuals, 605 returned positive results at least once, with prevalence significantly higher in men. A reduction of the level of viral RNA in the first swab per each positive patient collected over time was also observed. Moreover, 81 patients had at least one positive sample and two final negative tests: positivity in swabs lasted from 14 to 63 days, with a median value of 30 days. This shows the potential for the virus to coexist with patients for a long time, although we highlighted intermittent positivity in several cases. The evolution of the SARS-CoV-2 epidemiological situation and knowledge on viral shedding should be closely monitored, to interpret the findings correctly and adjust accordingly the surveillance activities.

Highlights

Eighteen years after the emergence of severe acute respiratory syndrome (SARS) in China, and eight years after the emergence of Middle East respiratory syndrome (MERS) in Saudi Arabia, a novel coronavirus (CoV) epidemic of a probable animal origin, acknowledged as a pandemic on March 11 2020 by the WHO [1], is threatening the human population worldwide [2].The disease, referred to as coronavirus disease 2019 (COVID-19) [3], is caused by a novel human CoV named SARS coronavirus 2 (SARS-CoV-2) [4,5]
This virus belongs to the species Severe acute respiratory syndrome-related coronavirus (SARS-rCoV), sub genus Sarbecovirus, genus Betacoronavirus, sub family Orthocoronavirinae, family Coronaviridae, with other known viruses mainly identified in humans, wild carnivores, and bats [5,6]
In addition to a wide overview of the results originating from SARS-CoV-2 diagnostic activities performed at IZSAM in the last 3 months, this paper mainly focuses upon SARS-CoV-2 RNA persistence in naso-pharyngeal/oropharyngeal swabs

Summary

Introduction

The disease, referred to as coronavirus disease 2019 (COVID-19) [3], is caused by a novel human CoV named SARS coronavirus 2 (SARS-CoV-2) [4,5] This virus belongs to the species Severe acute respiratory syndrome-related coronavirus (SARS-rCoV), sub genus Sarbecovirus, genus Betacoronavirus, sub family Orthocoronavirinae, family Coronaviridae, with other known viruses mainly identified in humans, wild carnivores, and bats [5,6]. Despite China and many other countries promptly placing various control measures [7], sustained human-to-human transmission of SARS-CoV-2 occurred rapidly outside Wuhan [8] and by the end of January 2020, about 20 other countries reported COVID-19 cases internationally [9]. Since the emergence of SARS-CoV-2, more than 6.2 million COVID-19 cases were reported globally [10] (up to the 3rd of June). On March 9th, in response to the growing number of cases reported, emergency measures based on the restriction of human mobility, social distancing, and closure of all non-essential services were extended to the whole country [13]

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