key: cord-0960865-z6lat678 authors: Ranshing, Sujata; Lavania, Mallika; Potdar, Varsha; Patwardhan, Sampada; Prayag, Parikshit S.; Jog, Sameer; Kelkar, Dhananjay; Sawant, Pradeep; Shinde, Manohar; Chavan, Nutan title: Transmission of COVID-19 infection within a family cluster in Pune, India date: 2021 journal: Indian J Med Res DOI: 10.4103/ijmr.ijmr_3378_20 sha: 8855fb56b61598e39aa024c8dd83fb2d73065ba0 doc_id: 960865 cord_uid: z6lat678 nan There are reports from China on SARS-CoV-2 infection in a family setting with person-to-person transmission 3, 4 . There are no studies on family cluster reported from India which is the leading mode of human-to-human transmission [3] [4] [5] . In the present study, we report the clinical and laboratory findings, and a transmission pattern of four patients in a family cluster from Pune city. All four members presented with different clinical features after being infected with COVID-19. The index case contracted this infection from the hospital and subsequently infected other members in the family. The present study was a part of a hospital-based study initiated at the Indian Council of Medical Research-National Institute of Virology (ICMR-NIV), Pune, to investigate the SARS-CoV-2 shedding in excreta of COVID-19 patients during treatment and after recovery. The study was approved by the ethics committees of the institute and the hospital. The family that had four members in total was admitted for COVID-19 treatment. Written informed consent was obtained before the study. The index case was a 37 yr old male (index), a healthcare worker, who had worked in the COVID-19 ward. He was living with his wife (34 yr old) and two children (8 and 6 yr old). Being a healthcare worker, index had been exposed to multiple laboratory-confirmed COVID-19 patients. The index patient presented with fever, nasal discharge and generalized weakness on the onset of symptoms. He was admitted in the hospital and diagnosed with COVID-19 by realtime reverse transcriptase-polymerase chain reaction (rRT-PCR) using throat/nasal swabs as per the protocol published by the WHO 6 . On the fourth day of onset of symptoms, his wife (case 1) developed sore throat and rhinorrhoea. Case 1 along with two children (cases 2-3) was admitted on the sixth day of onset of symptoms in the index case, as they were confirmed positive for COVID-19 by rRT-PCR. Both the children were asymptomatic throughout the disease. An asymptomatic case was defined as a laboratory-confirmed COVID-19 infection case who was afebrile and well. None of the patients had diarrhoea as a part of their symptoms. All family members were discharged from the hospital by day 14 of the admission of the index case. Stool and urine samples were collected from all these patients on admission to check if the virus could be detected in specimens from non-respiratory sites and 14 days after collection of the first specimens (based on the incubation period of the virus). Additional stool samples were collected from the index case on 21, 32, 40, 48 and 55 days after the onset of symptoms to determine the duration of excretion of this novel virus in faeces. The viral nucleic acids were extracted from 30 per cent (w/v) suspensions in phosphate-buffered saline (pH 7.2-7.4) using spin columns (Qiagen, Hilden, Germany) as per manufacturer's instructions and determined by rRT-PCR targeting the genes, E (envelope), RdRp (RNA dependent RNA polymerase), ORF-1b-nsp14 (Open Reading Frame) and RNaseP (human RNase P) gene as internal control 7 . Viral copy numbers were quantified using E quantitative PCR standards developed at ICMR-NIV in ten-fold serial dilutions to generate a standard curve 8 . The family cluster of four (index case and cases 1-3) was infected with SARS-CoV-2. The timeline of contact and the duration of transmission of disease within the family as measured by rRT-PCR are indicated in Fig. 1 . All the cases showed positivity in stool samples on days 8, 14 and 21 where higher viral loads corresponding to lower Ct values for E and ORF-1b-nsp14 genes were observed and no significant difference in Ct values of symptomatic and asymptomatic patients was observed (Fig. 2) . However, on day 32, cases 2 and 3 became negative and case 1 was negative on the fortieth day. Furthermore, the index patient continued to excrete virus in stool until 48 days despite throat/nasal swab was found negative (Fig. 3) . The viral shedding profile (Fig. 3) showed that the shedding increased slightly on day 6, peaked on the day 14 after the onset of illness and then dropped gradually to lower levels on day 55. Urine specimens of all the patients were negative. In general, the Ct values of ORF-1b-nsp14 gene for all specimens were lower compared to that of RdRp gene confirming earlier studies 9 that ORF-1b-nsp14-based assay performed well as a confirmatory assay as compared to RdRp-based assays. The clinical features were diverse across the family; both the children were asymptomatic, the wife with mild symptoms and the index case had more severe respiratory symptoms. It was observed in this study that the transmission of SARS-CoV-2 infection occurred during the incubation period. A study done by Zou et al 10 found that the viral loads of symptomatic and asymptomatic patients were similar and asymptomatic patients could infect others. Correlation of extended viral shedding in faeces in severe cases needs to be determined. Our observations are in concordance with reports that children develop mild or even asymptomatic illness compared to adults and elderly persons, and they may fare better when they have contracted the virus 4,5,11 . Viral RNA was not detectable in urine specimens of these patients. However, improved methods of testing of urine samples are warranted. A rather surprising finding from the study was detection of viral RNA from the faecal specimens of the patients, though none of them had diarrhoea as part of their symptoms. Our study had a few limitations. SARS-CoV-2 was not isolated by the culture method from the samples that tested positive for the SARS-CoV-2 E gene by rRT-PCR. Real-time PCR detects viral RNA genome which can represent a replicating or a non-viable non-replicating virus. Angiotensinconverting enzyme 2, the receptor for spike protein COVID-19 coronavirus pandemic Coronavirus disease (COVID-2019) situation reports. WHO; 2020 A familial cluster of pneumonia associated with the 2019 novel coronavirus indicating person-to-person transmission: A study of a family cluster Clinical and epidemiological features of COVID-19 family clusters in Beijing Children infected with SARS-CoV-2 from family clusters Coronavirus disease (COVID-19) technical guidance: Laboratory testing for 2019-nCoV in humans Laboratory preparedness for SARS-CoV-2 testing in India: Harnessing a network of Virus Research & Diagnostic Laboratories Development of in vitro transcribed RNA as positive control for laboratory diagnosis of SARS-CoV-2 in India Evaluation of RdRp & ORF-1b-nsp14-based real-time RT-PCR assays for confirmation of SARS-CoV-2 infection: An observational study SARS-CoV-2 viral load in upper respiratory specimens of infected patients A COVID-19 transmission within a family cluster by presymptomatic infectors in China SARS-CoV-2 productively infects human gut enterocytes The authors thank Dr Priya Abraham, Director ICMR-NIV, Pune, for the support during the study. The authors are grateful to Dr M L Chaudhary (Influenza Group, ICMR-NIV, Pune) for coordination with hospital laboratory authority for clinical sample from known SARS-CoV-positive patient. The assistance provided by Servshri P.S. Jadhav and Santosh (Deenanath Mangeshkar Hospital, Pune) during sample collection from the hospital and technical help by Shri R. Doiphode is duly acknowledged. The authors are thankful to NIC Team for supplying reagents for testing. Smt Veena Vipat is acknowledged for providing technical support for viral load detection.