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We thank Goyal et al for their interest in our study reporting on the course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease 2019 (COVID-19) in a case series of patients with systemic lupus erythematosus (SLE) under long-term treatment with hydroxychloroquine.1 2 Goyal et al, on a series of 845 patients with SLE, reported symptoms compatible with COVID-19 in 17 (2.0%) and confirmed COVID-19 in only 1 (0.1%) of the patients. The very low frequency of COVID-19 in these patients reflects the low incidence of SARS-Cov-2 infection in the Indian population at the completion of their study. However, since then, the epidemic has unfortunately progressed and the number of deaths from COVID-19 in India has multiplied nearly 10-fold. Thus, the number of patients with SLE affected by COVID-19 is probably much higher now than that reported by Goyal et al at the beginning of the epidemic. The network of rheumatology centres that was created during this multicentric survey will make it possible to collect new information concerning the occurrence of SARS-CoV-2 infection in patients with SLE in India. However, we would like to insist on the necessity to use reliable markers to establish the diagnosis of COVID-19 such as viral detection by real-time reverse transcription-PCR analysis and/or the detection of anti-SARS-CoV-2 serum antibodies. In addition, a chest CT scan suggestive of SARS-CoV-2 pneumonia will also allow, in the context of a COVID-19 outbreak, to confirm the diagnosis of SARS-CoV-2 infection. Unfortunately, Goyal et al reported that only 2 out of 17 patients who reported fever, cough or shortness of breath were tested for infection with SARS-CoV-2. In the context of the low attack rate, observed at the beginning of the pandemic in India, the occurrence of this symptomatology is not synonymous with COVID-19 because infection with virus strains other than SARS-CoV-2 may cause similar, indistinguishable symptoms. We therefore insist on the use of the aforementioned diagnostic methods to improve the reliability of this type of study.
To conclude, if the attack rate in the general population remains low in the foreseeable future, it will be useful to regroup the different observational cohorts from various countries and continents permitting to better identify, and with a gain of statistical power, the potential risk factors for severe COVID-19 in patients with lupus, provided that the diagnosis of COVID-19 is certain.3–6
Handling editor Josef S Smolen
Contributors AM and ZA wrote the manuscript.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Provenance and peer review Commissioned; internally peer reviewed.
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