Is the conclusion available? Letter to the Editor concerning the study of Prof. Jin titled “Clinical features and outcomes of pregnant women suspected of coronavirus disease 2019”
Authors: Han Xie, Hao Ying
Journal: Journal of Infection (2020)

We have read with great interest a recent study of Prof. Jin regarding the clinical features and outcomes of pregnant women suspected of 2019 novel coronavirus disease (COVID-19)1Yang H Sun G Tang F Peng M Gao Y Peng J Xie H Zhao Y Jin Z Clinical features and outcomes of pregnant women suspected of coronavirus disease 2019.J Infect. 2020 Apr 12; (pii: S0163-4453(20)30212-7)https://doi.org/10.1016/j.jinf.2020.04.003Abstract Full Text Full Text PDF Scopus (111) Google Scholar, especially the significance of pulmonary CT scan plus blood routine examination for screening COVID-19. Due to the worldwide outbreak of infection in the past few months, there were quite a number of urgent hospital admissions for delivery, many effective measures have been taken to reduce the incidence of nosocomial infection and the expansion of the epidemic. We are glad to see that the study investigators including Prof. Jin have strictly implemented the isolation protocol, and established the exact procedure for the patients to be diagnosed and referred actively, which has minimized the adverse prognosis and prevented further spreading of virus, thus protecting mothers and infants against COVID-19 infection. This is an extremely commendable achievement. However, we were a little puzzled about the conclusion from the results. The results showed that, there was no statistical difference between the confirmed COVID-19 group and the control group (p>0.05) for the imaging of pulmonary CT scan, blood routine examination, and clinical symptoms. These results may lead to the conclusion from this retrospective analysis that the clinical symptoms and laboratory indicators were not obvious for asymptomatic and mild COVID-19 pregnant women. Nevertheless, these results didn't support the conclusion that "Pulmonary CT scan plus blood routine examination are more suitable for finding pregnancy women with asymptomatic or mild COVID-19 infection and can be used screening COVID-19 pregnant women in the outbreak area of COVID-19 infection." The effectiveness of a test method should be evaluated between the outcome of the population who have been screened versus who have not been screened. Effective screening methods usually have higher sensitivity, which is a higher diagnosis rate in the screened population and a lower missed diagnosis in the non-screened population2Kowada A. Interferon-gamma release assay for tuberculosis screening of solid-organ transplant recipients is cost-effective.J Infect. Jan 2019; 78: 58-65https://doi.org/10.1016/j.jinf.2018.07.003Abstract Full Text Full Text PDF PubMed Scopus (7) Google Scholar. In this paper, however, the confirmed group has included the patients with positive sever acute respiratory syndrome coronavirus 2(SARS-CoV-2) via maternal throat swab test, while the control group included the patients already ruled out of COVID-19. Additionally, all the patients in each group have experienced pulmonary CT scan, blood routine examination and assessment of symptoms, while no patient without these screening methods have been included in this study. Therefore, the effectiveness of the screening method has not been properly evaluated. We considered, based on the results that, there was no statistical difference between the confirmed COVID-19 group and the control group in the imaging of pulmonary CT scan, blood routine examination, and clinical symptoms, the conclusion might be: The clinical symptoms and laboratory indicators were not obvious for asymptomatic and mild COVID-19 pregnant women. These screening methods cannot effectively distinguish between asymptomatic or mild confirmed cases and suspected patients. Therefore, strict isolation measures and procedures and early diagnosis for suspected pregnant women are essential in the epidemic area. This is exactly what the author has implemented and already achieved, like many other obstetricians3Peck KR Early diagnosis and rapid isolation: response to COVID-19 outbreak in Korea.Clin Microbiol Infect. 2020 Apr 25; (pii: S1198-743X (20)30233-0)https://doi.org/10.1016/j.cmi.2020.04.025Abstract Full Text Full Text PDF Scopus (75) Google Scholar, 4Yetmar ZA Issa M Munawar S Burton MC Pureza V Sohail MR Mehmood T Inpatient Care of Patients with COVID-19: A Guide for Hospitalists.Am J Med. 2020 Apr 24; (pii: S0002-9343(20)30349-1)https://doi.org/10.1016/j.amjmed.2020.03.041Abstract Full Text Full Text PDF Scopus (15) Google Scholar, 5Rasmussen SA Smulian JC Lednicky JA Wen TS Jamieson DJ Coronavirus Disease 2019 (COVID-19) and pregnancy: what obstetricians need to know.Am J Obstet Gynecol. 2020 Feb 24; (pii: S0002-9378(20)30197-6)https://doi.org/10.1016/j.ajog.2020.02.017Abstract Full Text Full Text PDF PubMed Scopus (766) Google Scholar, 6Rasmussen SA Jamieson DJ Coronavirus Disease 2019 (COVID-19) and Pregnancy: Responding to a Rapidly Evolving Situation.Obstet Gynecol. May 2020; 135: 999-1002https://doi.org/10.1097/AOG.0000000000003873Crossref PubMed Scopus (68) Google Scholar. It will also provide helpful information for other obstetricians who are currently experiencing the outbreak of COVID-19. In addition, there were two important items missing in this paper, which might lead to the discrepancy of the results. (1) What is the inclusion criteria in "Study design and patients"? (2) What is the definition of "suspected cases"? According to the original manuscript "The suspected cases of COVID-19 infection were screened based on pulmonary CT scan and routine blood test in combination with symptoms such as fever, cough, chest tightness or gastrointestinal symptoms, and admitted to an isolated suite in our hospital." It would be better for the authors to clarify were these items the inclusion criteria or the observed indicators? If pulmonary CT scan and routine blood test combination with symptoms have been the inclusion criteria, then what kind of testing results should be defined as suspected cases for the study, and what kind of patients need to do the pulmonary CT scan? Because we noticed that not all symptoms, images of pulmonary CT scan and blood indexes were positive in the study results. According to the disease situation at that time, we speculated that the inclusion criteria might be the definition of suspected cases in Diagnosis and Treatment Protocol for Novel Coronavirus Pneumonia (Trial Version 7) (Box 1) 7Guidelines for the diagnosis and treatment of coronavirus disease 2019 (trial version 7). (Released by National Health Commission & State Administration of Traditional Chinese Medicine on March 3, 2020). Available from:http://www.nhc.gov.cn/yzygj/s7653p/202003/46c9294a7dfe4cef80dc7f5912eb1989.shtml. [in Chinease].https://www.elotus.org/promo-files/COVID-19_resources/Guidance%20for%20Corona%20Virus%20Disease%202019%20(English%207th%20Edition%20Draft).pdf[in English]Google Scholar. If these definitions of suspected cases have been used as the inclusion criteria, all of the 55 suspect patients in this paper were suffering from at least two of the clinical manifestations. Was it appropriate to use these inclusion criteria as observation indicators at the same time? Furthermore, many studies have suggested the importance of pulmonary CT scan for the screening and the diagnosis of COVID-198Wu F Huang W. COVID-19 diagnostic process in mainland China: the math beyond pneumonia.J Allergy Clin Immunol. 2020 Apr 25; (pii: S0091-6749(20)30562-5)https://doi.org/10.1016/j.jaci.2020.04.015Abstract Full Text Full Text PDF Scopus (5) Google Scholar. However, the sensitivity of CT scan results has been largely affected by the disease severity, the proportion of patients with comorbidities, and the proportion of asymptomatic patients9Kim H Hong H Yoon SH Diagnostic Performance of CT and Reverse TranscriptasePolymerase Chain Reaction for Coronavirus Disease 2019: A Meta-Analysis.Radiology. 2020 Apr 17; 201343https://doi.org/10.1148/radiol.2020201343Crossref PubMed Scopus (381) Google Scholar. This may explain why there was no significant difference about the imaging of pulmonary CT scan between two groups in this paper, since the confirmed group had much less patients than the control group, and many of them were asymptomatic or mild patients. However, can we suggest the author to explore the different combinations of CT, blood test and symptom as the observation index? Probably a screening model with a higher diagnosis rate could be established to further improve the efficiency and quality of screening. Finally, we would appreciate Jin et al. for their original work, but further rigorous design and logical conclusion are still required.Tabled 1Box 1, Case DefinitionsSuspect casesConsidering both the following epidemiological history and clinical manifestations:Epidemiological history1.1.1 History of travel to or residence in Wuhan and its surrounding areas, or in other communities where cases have been reported within 14 days prior to the onset of the disease;1.1.2 In contact with novel coronavirus infected people (with positive results for the nucleic acid test) within 14 days prior to the onset of the disease;1.1.3 In contact with patients who have fever or respiratory symptoms from Wuhan and its surrounding area, or from communities where confirmed cases have been reported within 14 days before the onset of the disease; or1.1.4 Clustered cases (2 or more cases with fever and/or respiratory symptoms in a small area such families, offices, schools etc. within 2 weeks).Clinical manifestations1.2.1 Fever and/or respiratory symptoms;1.2.2 The aforementioned imaging characteristics of novel coronavirus pneumonia (NCP) (In the early stage, imaging shows multiple small patchy shadows and interstitial changes, apparent in the outer lateral zone of lungs. As the disease progresses, imaging then shows multiple ground glass opacities and infiltration in both lungs. In severe cases, pulmonary consolidation may occur while pleural effusion is rare);1.2.3 Normal or decreased WBC count, normal or decreased lymphocyte count in the early stage of onset.A suspect case has any of the epidemiological history plus any two clinical manifestations or all three clinical manifestations if there is no clear epidemiological history.Confirmed casesSuspect cases with one of the following etiological or serological evidences:2.1 Real-time fluorescent RT-PCR indicates positive for new coronavirus nucleic acid;2.2 Viral gene sequence is highly homologous to known new coronaviruses.2.3 NCP virus specific Ig M and IgG are detectable in serum; NCP virus specific IgG is detectable or reaches a titration of at least 4-fold increase during convalescence compared with the acute phase. Open table in a new tab The authors declare that there are no conflicts of interest.