Postmortem nasopharyngeal swabs performed during the COVID-19 infection: Analysis of preliminary clinical records by the genoa institute of legal medicine (North-West Italy)

COVID-19, the disease caused by the SARS-CoV-2 virus, is highly contagious. The persistence of the virus after infected individuals die remains unclear. This article reports the findings taken from postmortem nasopharyngeal swabs performed to investigate the presence of SARS-CoV-2 in the corpses transferred to the Genoa District Mortuary from the outset of the Italian lockdown (March 9) to the end of the first emergency phase (July 13). One hundred and eighty swabs were carried out: 13 corpses resulted positive for the virus, with the diagnosis being reached only after death. Seven were male and 6 female with an average age of 73.5 years old. The most frequent comorbidities recorded were arterial hypertension, diabetes, Alzheimer's, and pulmonary disease. In two cases, the swab tested positive at a distance of 125 h and 165 h from actual death. The nasopharyngeal swab results a useful way to screen corpses for COVID-19 and to handle bodies in Legal Medicine Centers where safe autoptic rooms are not available. Swabs are also a means of safeguarding forensic pathologists, identifying the presence of breeding grounds in the community and providing information for the Public Prosecutor's Office in legal cases. They are able to produce reliable results up to at least 7 days following death, provided that the corpse is correctly preserved.

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

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.

Epidemiological Significance of SARS-CoV-2 RNA Dynamic in Naso-Pharyngeal Swabs.

From 16 March to 15 December 2020, 132,357 naso-pharyngeal/oropharyngeal swabs were collected in the province of Teramo, Abruzzo Region, Italy, and tested for the presence of SARS-CoV-2 genomic RNA by a commercially available molecular assay. A total of 12,880 swabs resulted positive. For 8212 positive patients (4.150 women and 4.062 men) the median age was statistically different between women (median: 49.55 ± 23.9 of SD) and men (median: 48.35 ± 23.5 of SD) while no differences were found in the comparison between the cycle threshold for the N protein-encoding gene (CT N) median values and gender. Differences were observed in the CT N gene median values of swabs collected from March to September as well as in the pairwise comparison between September and October and between November and December. The CT N gene median values observed in specific periods characterizing the SARS-CoV-2 epidemic in 2020 were also compared with the incidence of COVID-19 cases; a strong inverse correlation was highlighted (Pearson correlation coefficient = -0.978). Our findings confirm the usefulness of the CT N values as an indirect detection parameter to monitor viral loads in the population.

Salivary SARS-CoV-2 antigen rapid detection: A prospective cohort study.

BACKGROUND AND AIM: SARS-CoV-2 quick testing is relevant for the containment of new pandemic waves. Antigen testing in self-collected saliva might be useful. We compared salivary and naso-pharyngeal swab (NPS) SARS-CoV-2 antigen detection by a rapid chemiluminescent assay (CLEIA) and two different point-of-care (POC) immunochromatographic assays, with results of molecular testing. METHODS: 234 patients were prospectively enrolled. Paired self-collected saliva (Salivette) and NPS were obtained to perform rRT-PCR, chemiluminescent (Lumipulse G) and POC (NPS: Fujirebio and Abbott; saliva: Fujirebio) for SARS-CoV-2 antigen detection. RESULTS: The overall agreement between NPS and saliva rRT-PCR was 78.7%, reaching 91.7% at the first week from symptoms. SARS-CoV-2 CLEIA antigen was highly accurate in distinguishing positive and negative NPS (ROC-AUC = 0.939, 95%CI:0.903-0.977), with 81.6% sensitivity and 93.8% specificity. This assay on saliva reached the optimal value within 7 days from symptoms onset (Sensitivity: 72%; Specificity: 97%). Saliva POC antigen was limited in sensitivity (13%), performing better in NPS (Sensitivity: 48% and 66%; Specificity: 100% and 99% for Espline and Abbott respectively), depending on viral loads. CONCLUSIONS: Self-collected saliva is a valid alternative to NPS for SARS-CoV-2 detection by molecular, but also by CLEIA antigen testing, which is therefore potentially useful for large scale screening.

Is naso-pharyngeal swab always safe for SARS-CoV-2 testing? An unusual, accidental foreign body swallowing.

Long and sharp objects can be foreign body intentionally or accidentally ingested. Timing of endoscopy relies on foreign body shape and size, localization in gastrointestinal tract, patient's clinical conditions, occurrence of symptoms, or onset of complications. We present a case of a 47-year-old male with no known comorbidity, who accidentally swallowed a portion of a naso-pharyngeal swab half-broken during the second diagnostic test for SARS-CoV-2. The intact swab had a total length of 15 cm and was made of wood. The patient was asymptomatic, laboratory tests were normal, and neck-chest-abdominal X-ray and CT scan were negative for major complications. Upper gastrointestinal endoscopy was promptly performed to prevent the long sharp swab from crossing the pylorus leading to serious complications and, therefore, risk surgical intervention. The patient was intubated and the procedure was carried out under general anesthesia. In the gastric body, broken naso-pharyngeal swab was detected among the food debris, and using a latex rubber hood, the 7.5 cm foreign body was removed with a retrieval alligator-tooth forceps. Our hospital is located in a high-risk area of COVID-19 outbreak where many naso-pharyngeal swabs are performed, and to our knowledge, this is the first report of swab ingestion during SARS-CoV-2 test.

SARS-CoV-2 identification and IgA antibodies in saliva: One sample two tests approach for diagnosis.

AIM: This study aims to verify whether standardized saliva collection is suitable for SARS-CoV-2 molecular detection and IgA measurement. METHODS: 43 COVID-19 inpatients and 326 screening subjects underwent naso-pharyngeal (NP)-swab and saliva collection (Salivette). Inpatients also underwent repeated blood collections to evaluate inflammation and organs involvement. In all patients and subjects, SARS-CoV-2 (gene E) rRT-PCR was undertaken in saliva and NP-swabs. Salivary IgA and serum IgA, IgG, IgM were measured on inpatients' samples. RESULTS: NP-swabs and saliva were both SARS-CoV-2 positive in 7 (16%) or both negative in 35 (82%) out of 43 patients successfully included in the study. NP-swabs and saliva results did not perfectly match in one patient (saliva positive, NP-swab negative). Positive molecular results were significantly associated with disease duration (p = 0.0049). 326/326 screening subjects were SARS-CoV-2 negative on both NP-swabs and saliva. Among the 27 saliva samples tested for IgA, 18 were IgA positive. Salivary IgA positivity was associated with pneumonia (p = 0.002) and CRP values (p = 0.0183), not with other clinical and molecular data, or with serum immunoglubulins. CONCLUSIONS: A standardized saliva collection can be adopted to detect SARS-CoV-2 infection in alternative to NP-swabs. Preliminary data on salivary IgA support the use of saliva also for patient monitoring.