Interpretation
Since the peak of the outbreak, methods effectively prevent COVID-19 recurrence have been the focus. Studies have shown that asymptomatic infections are contagious [3]. Asymptomatic carriers can also be a source to propagate the outbreak. The literature reports SARS-CoV-2 test that turned positive in a discharged patient with COVID-19 [4]. Hospital outpatient clinics, which are specialized for epidemic prevention, are the first barrier to prevent infection in the hospital because inpatients are diagnosed here and admitted to the hospital. Officially released information from Wuhan indicated that there were still asymptomatic infections found every day as of May 8, 2020. The fact that no NAT-positive cases were found in our study may be related to our visit procedure, which includes monitoring body temperature and seriously inquiring about past histories. Three patients with COVID-19 discovered in the recovery period had concealed a history of infection at the time of their visit. When the test results indicated abnormalities (2 patients were NAT positive, 1 patient was IgM-positive and IgG-positive), the patients confessed their medical history. Patients are required to sign a notification form confirming that they have are no COVID-19 symptoms or exposure history. It is worth mentioning that online telemedicine has played an important role in the diagnosis and treatment of obstetrics and gynecology patients. Our online clinic services cover video consultations, text-picture counseling, and medicine delivery. This approach reduced the number of people congregating in the hospital after the peak of the outbreak.
The IgG-positive individuals with no history of COVID-19 probably had recovered asymptomatic SARS-CoV-2 infections. A previous study reported that 10.26% of patients in the hospital were IgG positive but were all IgM and NAT negative [5]. In this study, the IgG positive rate of 3.140% (33/1051) was lower than that in other reports. The possible cause is that the patients were all female, and most of them had infrequent social interaction because they were unwell. Studies have reported that 13.5% of pregnant women in New York were SARS-CoV-2-positive but asymptomatic at the peak of the outbreak [6]. No NAT positivity was found, and the IgM positivity rate in the 325 patients who were pregnant in our study was 0.615% (2/325). At the same time, our study suggests that abnormal uterine bleeding and gynecological tumor patients may be more susceptible to COVID-19 and deserve our research attention. Despite the low number of cases, follow-up information suggests that IgM-positive patients are less contagious.
Current methods of screening for SARS-CoV-2 infection are the NAT, chest CT scan and serological testing. Our results suggest that CT has limited performance accuracy for SARS-CoV-2 infection screening in obstetrics and gynecology outpatients without a medical or exposure history of COVID-19 or suspected symptoms. In areas where testing resources are limited, a strict visit procedure is even more important, and a primary screening with serological testing alone or in combination with the NAT might be sufficient to triage the obstetrics and gynecology outpatients without a contact history or symptoms of SARS-CoV-2 infection.