Positive RT-PCR tests among discharged COVID-19 patients in

Acknowledgments. We thank Brian Fung, PharmD, Evan Draper, PharmD,

Aaron Tande, MD, and the Mayo Clinic Enterprise Antimicrobial Stewardship

Team. We dedicate this article to the memory of Dr James Steckelberg, a pioneer

of antimicrobial stewardship.

Financial support. No financial support was provided relevant to this article.

Conflicts of interest. All authors report no conflicts of interest relevant to this

article.

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Travel Med Infect Dis 2020 [Epub ahead of print]. doi: 10.1016/j.tmaid.

2020.101663.

Positive RT-PCR tests among discharged COVID-19 patients in

Shenzhen, China

Xiujuan Tang MMed

, Shi Zhao MPhil

, Daihai He PhD

, Lin Yang PhD

, Maggie H. Wang PhD

, Yuan Li MMed

Shujiang Mei BS

and Xuan Zou MMed

Shenzhen Center for Disease Control and Prevention, Shenzhen, China,

JC School of Public Health and Primary Care, Chinese University of Hong Kong,

Hong Kong, China,

Department of Applied Mathematics, Hong Kong Polytechnic University, Hong Kong, China and

School of Nursing, Hong Kong Polytechnic

University, Hong Kong, China

To the Editor—According to the current guideline of the National

Health Commission of China, discharge of inpatients with the

coronavirus 2019 (COVID-19) infection in China have to fulfill

2 recovery criteria: (1) symptoms disappear and computed tomog-

raphy (CT) images become normal and (2) test negative for 2 con-

secutive times in reverse transcriptase-polymerase chain reaction

(RT-PCR) tests for SARS-CoV-2.

However, Lan et al

recently

reported 4 cases who were tested positive for SARS-CoV-2 at 5

days after discharge, suggesting positive status among discharged

patients.

To date, the prevalence and associated risk factors

remain unclear.

We investigated all 209 patients with laborator y-confirmed

SARS-CoV-2 infection who were discharged from the designated

hospital in Shenzhen, China, between January 23 and February 21,

2020. Demo graphic data, laboratory profile, clinical data, and CT

images were collected from these patients’ electronic medical

records. Throat swabs and anal swabs were collected from all

patients for RT-PCR tests according to the following scenarios:

(1) on February 18, 2020, for those discharged before February

12, 2019; (2) on February 19, 2020 for those discharged between

February 13 and 19, 2019; (3) on days 7 and 14 after discharge

thereafter. This study was approved by the Shenzhen Center for

Disease Control and Prevention review board and the need for

informed consent was waived. All data used in this work are avail-

able upon request and approval of Shenzhen Center for Disease

Control and Prevention.

We compared the settings in the study by Lan et al

with those

in this study (Appendix Table S1 online). Logistic regression mod-

els were adopted to explore the factors associ ated with the RT-PCR

test results. Odds ratios (ORs) were calculated for the probability of

positive test in throat swabs, or anal swabs, or either, and the rest

were considered negative in each of the 3 scenarios. The results are

as follows:

• Scenario 1: 9 positive RT-PCR test results from throat swabs

• Scenario 2: 13 positive RT-PCR test results from anal swabs

• Scenario 3: 22 positive RT-PCR for test results from either throat

or anal swabs

Normally, only scenario 3 should be considered, but we included

scenario 1 to be consistent with Lan et al.

Among all 209 discharged patients, 9 (4.3%) tested positiv e in

throat swabs only, 13 patients (6.2%) tested positive in anal swabs

only, and 22 (10.5%) tested positive in either. Together, 10.5% of

discharged patients showed virus shredding around an average of

4.7 days after discharge (range, 2–13 days). Under scenario 3, the

logistic regression models revealed that a high risk of positive test

Author for correspo ndence: Shi Zhao, E-mail: zhaoshi.cms[email protected]. Or Daihai

He, E-mail: daihai.h[email protected]. Or Shujiang Mei, E-mail: sjmei6[email protected].Or

Xuan Zou, E-mail: [email protected]om.

Authors of equal contribution.

Cite this article: Tang X, et al. (2020). Positive RT-PCR tests among discharged

COVID-19 patients in Shenzhen, China. Infection Control & Hospital Epidemiology, 41:

1110–1112, https://doi.org/10.1017/ice.2020.134

(http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.

1110 Xiujuan Tang et al

https://doi.org/10.1017/ice.2020.134 Published online by Cambridge University Press

was significantly associated with older age (OR, 0.95; 95% confi-

dence interval [CI], 0.93−0.98), diarrhea during hospital stage

(OR, 10.44; 95% CI, 1.60−68.16). The “during disease” stage

was the other significant factor, with an adjusted and 9.59 (95%

CI, 2.02−45.62) under scenarios 2 and 3, respectively.

Expectoration during the disease stage is also a significant factor,

with an adjusted OR of 4.00 (95% CI, 1.24−12.88) but only under

scenario 3 (Table 1).

Although the prevalence of virus was substantial (10.5%), no

infection was discovered among close contacts. Discharged

COVID-19 patients in Shenzhen are required to be self-isolated

for an additional 14 days after discharge to prevent the possible

transmission due to the positive test post discharge.

Although live SARS-CoV-2 virus has been found in stool sam-

ples in some cases,

the role of fecal–oral transmission remains

unclear. Among 209 patients, 10 (4.8%) had diarrhea, and this ratio

is slightly higher than the 3.8% rate based on 1,099 patients nation-

wide,

and 2 of 10 patients (20%) with diarrhea showed positive

tests post discharge with positive anal swabs. We report that

15.7% of patients <50 years old showed positive tests, while

2.4% of patients >50 years old showed positive tests from anal

swabs. The delay between discharge and RT-PCR result date

was negatively associated among positive cases of throat swabs,

with an adjusted OR of 0.36 (95% C I, 0.18−0.72). This finding

implies that the risk of positive tests gradually vanishes over time.

Our study was limited by the lack of treatment information.

Further and large-scale study on this phenomenon is warranted.

Nevertheless, this study sheds lights on the viral dynamics of

COVID-19.

Supplementary material. To view supplementary material for this article,

please visit https://doi.org/10.1017/ice.2020.134

Table 1. Summary of the Characteristics of Study Patients and the Estimated Association Between the Individual Features and RT-PCR Testing Outcomes

Throat Swabs

Scenario 1

Positive

(N = 9)

Negative

(N = 200) Crude OR Adjusted OR

Sex Male 3 88 0.64 (0.15–2.71) 0.99 (0.27–3.62)

Age, y Median (IQR) 32 (28–36) 45 (32–57) 0.97 (0.93–1.00) 0.95 (0.92–0.99)

Sampling delay, d Median (IQR) 2 (2–2) 6 (3–7) 0.41 (0.21–0.81) 0.36 (0.18–0.72)

Symptoms

Dry cough 4 72 1.42 (0.36–5.65) 1.38 (0.44–4.32)

Expectoration 2 27 1.83 (0.35–9.67) 3.03 (0.61–15.1 4)

Cough 5 89 1.56 (0.39–6.19) 1.56 (0.52–4.70)

Diarrhea 1 9 2.65 (0.28–24.89) 7.01 (0.52–95.40)

Anal Swabs

Scenario 2

Positive

(N = 13)

Negative

(N = 196) Crude OR Adjusted OR

Sex Male 5 86 0.80 (0.25–2.61) 0.83 (0.28–2.46)

Age, y Median (IQR) 25 (6–39) 45 (32–58) 0.95 (0.91–0.98) 0.95 (0.92–0.98)

Sampling delay, d Median (IQR) 7 (5–7) 5 (2–7) 1.04 (0.91–1.19) 1.11 (0.97–1.26)

Symptoms

Dry cough 6 70 1.54 (0.48–4.91) 1.92 (0.65–5.63)

Expectoration 3 26 1.96 (0.49–7.87) 3.00 (0.67–13.3 7)

Cough 8 86 2.05 (0.63–6.67) 3.12 (0.97–10.07)

Diarrhea 2 8 4.27 (0.78–23.55) 10.44 (1.60–68.16)

Either Throat or Anal Swabs

Scenario 3

Positive

(N=22)

Negative

(N=187) Crude OR Adjusted OR

Sex Male 8 83 0.72 (0.28–1.83) 0.70 (0.29–1.66)

Age, y Median (IQR) 28 (20–38) 46 (32–59) 0.95 (0.93–0.98) 0.95 (0.93–0.98)

Sampling delay, d Median (IQR) 4 (2–7) 5 (3–7) 0.90 (0.77–1.05) 0.95 (0.81–1.10)

Symptoms

Dry cough 10 66 1.53 (0.61–3.81) 1.89 (0.81–4.39)

Expectoration 5 24 2.00 (0.66–6.08) 4.00 (1.24–12.8 8)

Cough 13 81 1.89 (0.75–4.75) 2.70 (1.12–6.51)

Diarrhea 3 7 4.06 (0.93–17.64) 9.59 (2.02–45.62)

Note. RT-PCR, reverse transcriptase-polymerase chain reaction; OR, odds ratio; IQR, interquartile range.

The OR is adjusted by the age, sex, sampling delay, disease severity and the backgrounds of the healthcare staff who delivered the treatment.

Infection Control & Hospital Epidemiology 1111

https://doi.org/10.1017/ice.2020.134 Published online by Cambridge University Press

Acknowledgments. We thank the Luohu Center for Disease Control (CDC),

Futian CDC, Baoan CDC, Nanshan CDC, Longgang CDC, Yantian CDC,

Longhua CDC, Guangming CDC, Pingshan CDC, Dapeng CDC, Shenzhen

Samii Medical Center and Shenzhen Hezheng Hospital, all in Shenzhen,

China, for offering 14-day isolation services for the discharged patients. We

thank the Third People’s Hospital of Shenzhen for the admission and treatment

for the relapse patients.

Financial support. D.H. was suppor ted by General Research Fund (grant

no. 1520511 9) of Re search Grants Council of H ong Kong and an Alibaba

(China)-Hong Kong Polytechnic University Collaborative R esearch project .

The funding agencies had no role in the design and conduct of the s tudy;

collection, management, analysis, and interpretation of the data; prepara-

tion, review, or approval of the ma nuscript; or decision to submit the manu-

script for publication.

Conflicts of interest. D.H. was supported by an Alibaba (China)-Hong Kong

Polytechnic University Collaborative Research project. All other authors

declared no competing interests related to this article.

References

1. China National Health Commission. Diagnosis and treatment of the novel

coronavirus (2019-nCoV) pneumonia in China [in Chinese]. China National

Health Commission website. http://www.nhc.gov.cn/yzygj/s7653p/202002/

d4b895337e1944 5f8d728fca f1e3e13a.s html. Published 2020. Accessed

April 16, 2020.

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from COVID-19. JAMA 2020. doi: 10.1001/jama.2020.2783.

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2019 in China. N Engl J Med 2020. doi: 10.1056/NEJMoa2002032.

Pasteurized blood samples for transfusion compatibility testing

during the coronavirus disease 2019 outbreak

Run Yao MS

, Yamei Shen BS

, Ying Tan MD

, Pengcheng Zhou MD

, Bijuan Li PhD

, Xuegong Fan PhD

and Ning Li PhD

Department of Blood Transfusion, Xiangya Hospital, Central South University, Changsha, 410007, Hunan, China,

Department of Infectious Diseases, Xiangya

Hospital, Central South University, Changsha, China and

Key Laboratory of Viral Hepatitis, Hunan Province, Changsha, China

To the Editor—In December 2019, a novel coronavirus pneumonia

(COVID-19) was reported in Wuhan, China. As of April 2, 2020,

82,774 confirmed cases had been reported in China and 874,995

confirmed cases had been reported in other countries. No vaccine

or antiviral therapeutics are yet available to prevent or treat

COVID-19.

Preventing infection is the current priority for disease

control.

The SARS-CoV-2 virus is transmitted from person to person

through droplets or direct contact.

However, non-respiratory

samples are also potential sources of C OVID-19 infection.

Virus-laden aerosols generated from blood-s ample centrifugation

pose risks for laboratory staff and broader nosocomial transmis-

sion.

3,4

Traditional precautionary measures for infectious-sample

processing include tertiary protection and operating in the biologi-

cal safety cabinet. Preventive resourc es have been limited during

this multiregional outbreak, posing huge risks to laboratory staff.

Therefore, effective methods to ensure the safety of laboratory staff

in low-resource settings are needed.

Pasteurization at 56°C for 30 minutes has been recommended

to inacti vate coronavirus, which might decrease the infectivity of

samples and aerosols. To reduce infections and ensure safe and

effective transfusion, we investigated the effects of pasteurization

on transfusion compatibility testing.

Methods

Blood samples were collected from Xiangya Hospital, Central

South University. Each sample was divided into 2 groups, an exper-

imental group and a control group. Experimental samples were

treated by pasteurization. The results of blood-group typing,

irregular antibody screening, and cross-matching were compared

between these 2 groups. Finally, samples of suspected SARS-CoV-2

were treated with pasteu rization. Treated samples were used to test

transfusion compatibility. Patients with suspected COVID-19 then

received red blood cell (RBC) transfusion, and the effectiveness and

safety of these transfusion were evaluated.

Results

The agglutination intensities of A, B antigens and anti-A, anti-B

antibodies of the samples in the 2 groups were 4þ. The forward

and reverse types were consistent in the ABO blood group. In

the Rh blood group, the agglutination intensity of D antigen

was reduced from 4þ to between 2þ and 3þ after heat treatment

(Fig. 1). Regarding the effect of heat treatment on irregular anti-

body screening, our result s showed that the response pattern of

panel cells remained unchanged after heat treatment when the

agglutination intensity was negative(-), uncertain(

) or zero,

and 1þ,2þ,or3þ, respectively. However, the agglutination inten-

sities of samples rating 4þ were reduced to 3þ after heat treatment

(Fig. 2). Finally, no effect of heat treatment on the primary cross-

matching was observed.

Our results indicated that heat treatment did not affect the

results of transfusion compatibility testing. The RBC transfusion

Author for correspondence: Li Ning, E-mail: [email protected]n

Cite this article: Yao R, et al. (2020). Pasteurized blood samples for transfusion

compatibility testing during the coronavirus disease 2019 outbreak. Infection Control &

Hospital Epidemiology, 41: 1112 –1114, https://doi.org/10.1017/ice.2020.138

(http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.

1112 Yao Run et al

https://doi.org/10.1017/ice.2020.134 Published online by Cambridge University Press