Patients with respiratory symptoms are at greater risk of COVID-19 transmission.

The situation with the ongoing epidemic of coronavirus disease 2019 (COVID-19) that started in Wuhan, China, continued to rapidly evolve. As of 10 March 2020, China had confirmed 80 754 cases of COVID-19 and there had been 3136 deaths. Except for China, 109 other nations have reported 32 555 cases and 878 deaths. The clinical and laboratory characteristics of hospitalized COVID-19 patients were described [1,2]. Cough is one of the most common symptoms at onset of illness [3]. Here, we described the differences in characteristics of nasopharyngeal swab detection between patients with and without respiratory symptoms.

The 82 COVID-19 patients were divided into respiratory symptoms group (26 cases) and non-respiratory symptoms group (56 cases). The two groups were comparable in gender (11 [42.3%] men vs 20 [35.7%] men; P = 0.567) and age (median age, 56 years [IQR, 35–65] vs 51 years [IQR, 36–64]; P = 0.398). Compared with patients who did not presented with respiratory symptoms, those patients who presented with cough were more likely to have longer duration of COVID-19 positive testing by nasopharyngeal swab (median duration, 17 days [IQR, 12–23] vs 13 days [IQR, 6–20]; P = 0.041), and have more stable results of COVID-19 testing by nasopharyngeal swab (24 [92.3%] vs 38 [67.9%], P = 0.016).

We believe that patients with respiratory symptoms are more harmful to close contacts. First, the virus can be shed explosively from the COVID-19 patients’ upper respiratory tract into the air through coughing. Second, the duration of virus shedding from nasopharynx was longer. It is an effective precaution to stop droplets spreading by hand or with towel when coughing. After coughing, the importance of frequent and proper hand hygiene should be emphasized. Moreover, strict precautions must be observed when handling the towel contaminated with spittle.

One encouraging finding is that the results of nasopharyngeal swabs are more stable in patients with cough symptoms. The incidence of nasopharyngeal swabs testing shown as negative and positive fluctuating repeatedly is less, which provides a basis for clinicians to better grasp the appropriate time to cancel quarantine based on the results of asopharyngeal swabs.

Fund program

Supported by , Grant NO. TFJC2018002.

Declaration of competing interest

We declare no competing interests.