Journal of Clinical and Diagnostic Research, ISSN - 0973 - 709X

Users Online : 83042

AbstractMaterial and MethodsResultsDiscussionConclusionAcknowledgementReferencesDOI and Others
Article in PDF How to Cite Citation Manager Readers' Comments (0) Audio Visual Article Statistics Link to PUBMED Print this Article Send to a Friend
Advertisers Access Statistics Resources

Dr Mohan Z Mani

"Thank you very much for having published my article in record time.I would like to compliment you and your entire staff for your promptness, courtesy, and willingness to be customer friendly, which is quite unusual.I was given your reference by a colleague in pathology,and was able to directly phone your editorial office for clarifications.I would particularly like to thank the publication managers and the Assistant Editor who were following up my article. I would also like to thank you for adjusting the money I paid initially into payment for my modified article,and refunding the balance.
I wish all success to your journal and look forward to sending you any suitable similar article in future"

Dr Mohan Z Mani,
Professor & Head,
Department of Dermatolgy,
Believers Church Medical College,
Thiruvalla, Kerala
On Sep 2018

Prof. Somashekhar Nimbalkar

"Over the last few years, we have published our research regularly in Journal of Clinical and Diagnostic Research. Having published in more than 20 high impact journals over the last five years including several high impact ones and reviewing articles for even more journals across my fields of interest, we value our published work in JCDR for their high standards in publishing scientific articles. The ease of submission, the rapid reviews in under a month, the high quality of their reviewers and keen attention to the final process of proofs and publication, ensure that there are no mistakes in the final article. We have been asked clarifications on several occasions and have been happy to provide them and it exemplifies the commitment to quality of the team at JCDR."

Prof. Somashekhar Nimbalkar
Head, Department of Pediatrics, Pramukhswami Medical College, Karamsad
Chairman, Research Group, Charutar Arogya Mandal, Karamsad
National Joint Coordinator - Advanced IAP NNF NRP Program
Ex-Member, Governing Body, National Neonatology Forum, New Delhi
Ex-President - National Neonatology Forum Gujarat State Chapter
Department of Pediatrics, Pramukhswami Medical College, Karamsad, Anand, Gujarat.
On Sep 2018

Dr. Kalyani R

"Journal of Clinical and Diagnostic Research is at present a well-known Indian originated scientific journal which started with a humble beginning. I have been associated with this journal since many years. I appreciate the Editor, Dr. Hemant Jain, for his constant effort in bringing up this journal to the present status right from the scratch. The journal is multidisciplinary. It encourages in publishing the scientific articles from postgraduates and also the beginners who start their career. At the same time the journal also caters for the high quality articles from specialty and super-specialty researchers. Hence it provides a platform for the scientist and researchers to publish. The other aspect of it is, the readers get the information regarding the most recent developments in science which can be used for teaching, research, treating patients and to some extent take preventive measures against certain diseases. The journal is contributing immensely to the society at national and international level."

Dr Kalyani R
Professor and Head
Department of Pathology
Sri Devaraj Urs Medical College
Sri Devaraj Urs Academy of Higher Education and Research , Kolar, Karnataka
On Sep 2018

Dr. Saumya Navit

"As a peer-reviewed journal, the Journal of Clinical and Diagnostic Research provides an opportunity to researchers, scientists and budding professionals to explore the developments in the field of medicine and dentistry and their varied specialities, thus extending our view on biological diversities of living species in relation to medicine.
‘Knowledge is treasure of a wise man.’ The free access of this journal provides an immense scope of learning for the both the old and the young in field of medicine and dentistry as well. The multidisciplinary nature of the journal makes it a better platform to absorb all that is being researched and developed. The publication process is systematic and professional. Online submission, publication and peer reviewing makes it a user-friendly journal.
As an experienced dentist and an academician, I proudly recommend this journal to the dental fraternity as a good quality open access platform for rapid communication of their cutting-edge research progress and discovery.
I wish JCDR a great success and I hope that journal will soar higher with the passing time."

Dr Saumya Navit
Professor and Head
Department of Pediatric Dentistry
Saraswati Dental College
On Sep 2018

Dr. Arunava Biswas

"My sincere attachment with JCDR as an author as well as reviewer is a learning experience . Their systematic approach in publication of article in various categories is really praiseworthy.
Their prompt and timely response to review's query and the manner in which they have set the reviewing process helps in extracting the best possible scientific writings for publication.
It's a honour and pride to be a part of the JCDR team. My very best wishes to JCDR and hope it will sparkle up above the sky as a high indexed journal in near future."

Dr. Arunava Biswas
MD, DM (Clinical Pharmacology)
Assistant Professor
Department of Pharmacology
Calcutta National Medical College & Hospital , Kolkata

Dr. C.S. Ramesh Babu
" Journal of Clinical and Diagnostic Research (JCDR) is a multi-specialty medical and dental journal publishing high quality research articles in almost all branches of medicine. The quality of printing of figures and tables is excellent and comparable to any International journal. An added advantage is nominal publication charges and monthly issue of the journal and more chances of an article being accepted for publication. Moreover being a multi-specialty journal an article concerning a particular specialty has a wider reach of readers of other related specialties also. As an author and reviewer for several years I find this Journal most suitable and highly recommend this Journal."
Best regards,
C.S. Ramesh Babu,
Associate Professor of Anatomy,
Muzaffarnagar Medical College,
On Aug 2018

Dr. Arundhathi. S
"Journal of Clinical and Diagnostic Research (JCDR) is a reputed peer reviewed journal and is constantly involved in publishing high quality research articles related to medicine. Its been a great pleasure to be associated with this esteemed journal as a reviewer and as an author for a couple of years. The editorial board consists of many dedicated and reputed experts as its members and they are doing an appreciable work in guiding budding researchers. JCDR is doing a commendable job in scientific research by promoting excellent quality research & review articles and case reports & series. The reviewers provide appropriate suggestions that improve the quality of articles. I strongly recommend my fraternity to encourage JCDR by contributing their valuable research work in this widely accepted, user friendly journal. I hope my collaboration with JCDR will continue for a long time".

Dr. Arundhathi. S
MBBS, MD (Pathology),
Sanjay Gandhi institute of trauma and orthopedics,
On Aug 2018

Dr. Mamta Gupta,
"It gives me great pleasure to be associated with JCDR, since last 2-3 years. Since then I have authored, co-authored and reviewed about 25 articles in JCDR. I thank JCDR for giving me an opportunity to improve my own skills as an author and a reviewer.
It 's a multispecialty journal, publishing high quality articles. It gives a platform to the authors to publish their research work which can be available for everyone across the globe to read. The best thing about JCDR is that the full articles of all medical specialties are available as pdf/html for reading free of cost or without institutional subscription, which is not there for other journals. For those who have problem in writing manuscript or do statistical work, JCDR comes for their rescue.
The journal has a monthly publication and the articles are published quite fast. In time compared to other journals. The on-line first publication is also a great advantage and facility to review one's own articles before going to print. The response to any query and permission if required, is quite fast; this is quite commendable. I have a very good experience about seeking quick permission for quoting a photograph (Fig.) from a JCDR article for my chapter authored in an E book. I never thought it would be so easy. No hassles.
Reviewing articles is no less a pain staking process and requires in depth perception, knowledge about the topic for review. It requires time and concentration, yet I enjoy doing it. The JCDR website especially for the reviewers is quite user friendly. My suggestions for improving the journal is, more strict review process, so that only high quality articles are published. I find a a good number of articles in Obst. Gynae, hence, a new journal for this specialty titled JCDR-OG can be started. May be a bimonthly or quarterly publication to begin with. Only selected articles should find a place in it.
An yearly reward for the best article authored can also incentivize the authors. Though the process of finding the best article will be not be very easy. I do not know how reviewing process can be improved. If an article is being reviewed by two reviewers, then opinion of one can be communicated to the other or the final opinion of the editor can be communicated to the reviewer if requested for. This will help one’s reviewing skills.
My best wishes to Dr. Hemant Jain and all the editorial staff of JCDR for their untiring efforts to bring out this journal. I strongly recommend medical fraternity to publish their valuable research work in this esteemed journal, JCDR".

Dr. Mamta Gupta
(Ex HOD Obs &Gynae, Hindu Rao Hospital and associated NDMC Medical College, Delhi)
Aug 2018

Dr. Rajendra Kumar Ghritlaharey

"I wish to thank Dr. Hemant Jain, Editor-in-Chief Journal of Clinical and Diagnostic Research (JCDR), for asking me to write up few words.
Writing is the representation of language in a textual medium i e; into the words and sentences on paper. Quality medical manuscript writing in particular, demands not only a high-quality research, but also requires accurate and concise communication of findings and conclusions, with adherence to particular journal guidelines. In medical field whether working in teaching, private, or in corporate institution, everyone wants to excel in his / her own field and get recognised by making manuscripts publication.

Authors are the souls of any journal, and deserve much respect. To publish a journal manuscripts are needed from authors. Authors have a great responsibility for producing facts of their work in terms of number and results truthfully and an individual honesty is expected from authors in this regards. Both ways its true "No authors-No manuscripts-No journals" and "No journals–No manuscripts–No authors". Reviewing a manuscript is also a very responsible and important task of any peer-reviewed journal and to be taken seriously. It needs knowledge on the subject, sincerity, honesty and determination. Although the process of reviewing a manuscript is a time consuming task butit is expected to give one's best remarks within the time frame of the journal.
Salient features of the JCDR: It is a biomedical, multidisciplinary (including all medical and dental specialities), e-journal, with wide scope and extensive author support. At the same time, a free text of manuscript is available in HTML and PDF format. There is fast growing authorship and readership with JCDR as this can be judged by the number of articles published in it i e; in Feb 2007 of its first issue, it contained 5 articles only, and now in its recent volume published in April 2011, it contained 67 manuscripts. This e-journal is fulfilling the commitments and objectives sincerely, (as stated by Editor-in-chief in his preface to first edition) i e; to encourage physicians through the internet, especially from the developing countries who witness a spectrum of disease and acquire a wealth of knowledge to publish their experiences to benefit the medical community in patients care. I also feel that many of us have work of substance, newer ideas, adequate clinical materials but poor in medical writing and hesitation to submit the work and need help. JCDR provides authors help in this regards.
Timely publication of journal: Publication of manuscripts and bringing out the issue in time is one of the positive aspects of JCDR and is possible with strong support team in terms of peer reviewers, proof reading, language check, computer operators, etc. This is one of the great reasons for authors to submit their work with JCDR. Another best part of JCDR is "Online first Publications" facilities available for the authors. This facility not only provides the prompt publications of the manuscripts but at the same time also early availability of the manuscripts for the readers.
Indexation and online availability: Indexation transforms the journal in some sense from its local ownership to the worldwide professional community and to the public.JCDR is indexed with Embase & EMbiology, Google Scholar, Index Copernicus, Chemical Abstracts Service, Journal seek Database, Indian Science Abstracts, to name few of them. Manuscriptspublished in JCDR are available on major search engines ie; google, yahoo, msn.
In the era of fast growing newer technologies, and in computer and internet friendly environment the manuscripts preparation, submission, review, revision, etc and all can be done and checked with a click from all corer of the world, at any time. Of course there is always a scope for improvement in every field and none is perfect. To progress, one needs to identify the areas of one's weakness and to strengthen them.
It is well said that "happy beginning is half done" and it fits perfectly with JCDR. It has grown considerably and I feel it has already grown up from its infancy to adolescence, achieving the status of standard online e-journal form Indian continent since its inception in Feb 2007. This had been made possible due to the efforts and the hard work put in it. The way the JCDR is improving with every new volume, with good quality original manuscripts, makes it a quality journal for readers. I must thank and congratulate Dr Hemant Jain, Editor-in-Chief JCDR and his team for their sincere efforts, dedication, and determination for making JCDR a fast growing journal.
Every one of us: authors, reviewers, editors, and publisher are responsible for enhancing the stature of the journal. I wish for a great success for JCDR."

Thanking you
With sincere regards
Dr. Rajendra Kumar Ghritlaharey, M.S., M. Ch., FAIS
Associate Professor,
Department of Paediatric Surgery, Gandhi Medical College & Associated
Kamla Nehru & Hamidia Hospitals Bhopal, Madhya Pradesh 462 001 (India)
On May 11,2011

Dr. Shankar P.R.

"On looking back through my Gmail archives after being requested by the journal to write a short editorial about my experiences of publishing with the Journal of Clinical and Diagnostic Research (JCDR), I came across an e-mail from Dr. Hemant Jain, Editor, in March 2007, which introduced the new electronic journal. The main features of the journal which were outlined in the e-mail were extensive author support, cash rewards, the peer review process, and other salient features of the journal.
Over a span of over four years, we (I and my colleagues) have published around 25 articles in the journal. In this editorial, I plan to briefly discuss my experiences of publishing with JCDR and the strengths of the journal and to finally address the areas for improvement.
My experiences of publishing with JCDR: Overall, my experiences of publishing withJCDR have been positive. The best point about the journal is that it responds to queries from the author. This may seem to be simple and not too much to ask for, but unfortunately, many journals in the subcontinent and from many developing countries do not respond or they respond with a long delay to the queries from the authors 1. The reasons could be many, including lack of optimal secretarial and other support. Another problem with many journals is the slowness of the review process. Editorial processing and peer review can take anywhere between a year to two years with some journals. Also, some journals do not keep the contributors informed about the progress of the review process. Due to the long review process, the articles can lose their relevance and topicality. A major benefit with JCDR is the timeliness and promptness of its response. In Dr Jain's e-mail which was sent to me in 2007, before the introduction of the Pre-publishing system, he had stated that he had received my submission and that he would get back to me within seven days and he did!
Most of the manuscripts are published within 3 to 4 months of their submission if they are found to be suitable after the review process. JCDR is published bimonthly and the accepted articles were usually published in the next issue. Recently, due to the increased volume of the submissions, the review process has become slower and it ?? Section can take from 4 to 6 months for the articles to be reviewed. The journal has an extensive author support system and it has recently introduced a paid expedited review process. The journal also mentions the average time for processing the manuscript under different submission systems - regular submission and expedited review.
Strengths of the journal: The journal has an online first facility in which the accepted manuscripts may be published on the website before being included in a regular issue of the journal. This cuts down the time between their acceptance and the publication. The journal is indexed in many databases, though not in PubMed. The editorial board should now take steps to index the journal in PubMed. The journal has a system of notifying readers through e-mail when a new issue is released. Also, the articles are available in both the HTML and the PDF formats. I especially like the new and colorful page format of the journal. Also, the access statistics of the articles are available. The prepublication and the manuscript tracking system are also helpful for the authors.
Areas for improvement: In certain cases, I felt that the peer review process of the manuscripts was not up to international standards and that it should be strengthened. Also, the number of manuscripts in an issue is high and it may be difficult for readers to go through all of them. The journal can consider tightening of the peer review process and increasing the quality standards for the acceptance of the manuscripts. I faced occasional problems with the online manuscript submission (Pre-publishing) system, which have to be addressed.
Overall, the publishing process with JCDR has been smooth, quick and relatively hassle free and I can recommend other authors to consider the journal as an outlet for their work."

Dr. P. Ravi Shankar
KIST Medical College, P.O. Box 14142, Kathmandu, Nepal.
On April 2011

Dear team JCDR, I would like to thank you for the very professional and polite service provided by everyone at JCDR. While i have been in the field of writing and editing for sometime, this has been my first attempt in publishing a scientific paper.Thank you for hand-holding me through the process.

Dr. Anuradha
On Jan 2020

Important Notice

Original article / research
Year : 2022 | Month : April | Volume : 16 | Issue : 4 | Page : OC28 - OC31 Full Version

Asymptomatic COVID-19 Infection among Healthcare Workers in Dedicated Tertiary Care Facility of Kolkata, India

Published: April 1, 2022 | DOI:
Debarup Das, Kaushik Basu, Lekha Biswas, Sidhartha Bhattacharya, Punnag Sarkar, Niharika Pant, Rishav Sanghai, Amarnath Thakur

1. Senior Resident, Department of General Medicine, Medical College and Hospital, Kolkata, West Bengal, India. 2. Assistant Professor, Department of General Medicine, Medical College and Hospital, Kolkata, West Bengal, India. 3. Assistant Professor, Department of Biochemistry, Medical College and Hospital, Kolkata, West Bengal, India. 4. Junior Resident, Department of Biochemistry, Medical College and Hospital, Kolkata, West Bengal, India. 5. Senior Resident, Department of General Medicine, Medical College and Hospital, Kolkata, West Bengal, India. 6. Medical Officer, Department of Oncology, Om Hospital and Research Centre, Kathmandu, Nepal. 7. Junior Resident, Department of Neurosurgery, Medical College and Hospital, Kolkata, West Bengal, India. 8. Senior Resident, Department of General Medicine, Medical College and Hospital, Kolkata, West Bengal, India.

Correspondence Address :
Dr. Debarup Das,
Senior Resident, Department of General Medicine, Medical College and Hospital, Kolkata, West Bengal, India.


Introduction: In view of the present Coronavirus Disease 2019 (COVID-19) pandemic it is of utmost importance to look out for the ‘trojan horse’ that is the asymptomatic population who are potential for spreading the disease. Healthcare Workers (HCWs) are the most vulnerable group. The possibility of having the infection does not always correlate well with the symptoms. It urges the need for development of certain special plans beyond continuous surveillance and symptom monitoring.

Aim: To explore asymptomatic COVID-19 infection among HCWs as a potential source of transmission.Materials and Methods: This hospital-based cross-sectional study was conducted at Medical College and Hospital, Kolkata, West Bengal, India, from June 2020 to September 2020. The data were collected from 714 HCWs over a period of three months of study period, with the help of a standard questionnaire and blood sample was analysed by serological assessment of Immunoglobulin G (IgG) for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) by EUROIMMUN Kit, Enzyme-Linked Immunosorbent Assay (ELISA). Epi info software 7, available from the World Health Organisation (WHO) site was used to manage and analyse the data.

Results: The mean age was 35.30±11.79 years. Out of 714 people, 54.8% (391/714) were male and 45.2% (323/714) were female. In this survey, 9.16% of HCWs in COVID-19 designated duties were IgG positive; whereas 21.89% of HCWs designated in other parts of area were detected to be IgG positive. Seroprevalence was least amongst nursing staffs with 5.41% (8/148); among doctor’s it was 9.62% (41/426). Most interestingly among ward boys and cleaners this prevalence was found to be 29.90% (29/97) being the highest. Overall seroprevalence for IgG against SARS-CoV-2 was found to be 12.75% (91/714).

Conclusion: This serosurvey at this tertiary COVID-19 care facility is a unique venture to look for the possible sources of super-spread. The high rate of sero-positivity among ward boys and cleaners might be due to their lack of knowledge and training regarding steps to prevent a droplet borne pandemic. This study also points out that if adequate precautions are taken, infectivity is not to an alarming extent, even in a full-fledged COVID-19 care hospital.


Coronavirus disease 2019, Euroimmun kit, Immunoglobulin G, Serosurvey, Serological study

On December 31, 2019, China reported a cluster of pneumonia cases of unknown cause that would later be identified as Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) (1),(2),(3),(4). Patients with the illness, called Coronavirus Disease 2019 (COVID-19), frequently present with fever, cough, and shortness of breath within 2-14 days after exposure (5). As of 21st September 2021, over 228 million COVID-19 cases and 4.6 million deaths have been reported globally (6). In recognition of the widespread global transmission of COVID-19, the World Health Organisation (WHO) declared COVID-19 to be a pandemic on 11th March 2020 (7). A total of 15,65,645 cases were reported in West Bengal with 7674 active cases (8). With case numbers and deaths, surging and making the curve grow steeper every day; it implies that a lot needs to be explored about this virus and the havoc it is creating on humans.

Unlike Severe Acute Respiratory Syndrome (SARS) or Middle East respiratory syndrome, COVID-19 was less virulent, with a lower mortality rate (9),(10),(11). Nevertheless, low virulence and longer incubation periods resulted in a significant number of asymptomatic carriers. These people might not take adequate precautions and thus could become a source of transmission (12). Thereby, a large part of transmission remains subclinical (13). There have been studies that have revealed infections spread by patients in the incubation period and by the asymptomatic carriers (14). Asymptomatic transmission could further increase the risk of super-spreading in hospitals (15).

Unlike Severe Acute Respiratory Syndrome (SARS) or Middle East respiratory syndrome, COVID-19 was less virulent, with a lower mortality rate (9),(10),(11). Nevertheless, low virulence and longer incubation periods resulted in a significant number of asymptomatic carriers. These people might not take adequate precautions and thus could become a source of transmission (12). Thereby, a large part of transmission remains subclinical (13). There have been studies that have revealed infections spread by patients in the incubation period and by the asymptomatic carriers (14). Asymptomatic transmission could further increase the risk of super-spreading in hospitals (15).

With less research in this area (16), present study aimed to cover the proportion of asymptomatic Healthcare Workers (HCWs) who might be involved in transmission of the COVID-19 infection in an otherwise non infected patient in a hospital setting. Thus, HCWs could be a potential carrier of the disease and identifying them at the right moment can serve as barrier to transmission.

Material and Methods

This hospital-based, cross-sectional study was conducted at Medical College and Hospital, Kolkata, West Bengal, India, from June 2020 to September 2020, on 714 HCWs. The ethical clearance was obtained from the Institutional Ethics Committee (approval no. MC/KOL/IEC/NON SPON/717/06/2020). This study was a joint venture between the Department of General Medicine and Department of Biochemistry of this Hospital (the largest and longest serving COVID-19 care facility hospital of West Bengal, possibly the entire Eastern and North-eastern India). A written informed consent was taken from all the participating HCWs.

Sample size calculation: Considering the worst case scenario method to calculate the required sample size, authors considered prevalence (p) as 50% and q (1-p) as 50%, z was considered at 99% confidence level with absolute error of 5% (d). It came out to be 660. Moreover, 10% excess data was considered due to attrition factor resulting in a target sample size of 720.

Inclusion criteria: Cases were defined as HCWs indulged in designated COVID-19 or suspect wards and other parts of the hospital were included in the study.

Exclusion criteria: Individuals with age group <18 years and HCWs with previous laboratory diagnosed COVID-19 were excluded from the study.


A complete questionnaire could be obtained from 725 subjects and collection blood sample was drawn in all 714 subjects. Thus, 11 subjects had to be excluded from data analysis and study population contains 714 subjects.

A brief history on the presence of symptoms like fever, cough, conjunctivitis etc., and any past medical history was taken. The data was collected from HCWs with the help of a self-made questionnaire (containing variables like job designation, type of COVID-19 designated duty, duration of such duty, episode of influenza like illness). The blood samples were collected from the HCWs for a period of three months from June 2020 to September 2020. A brief clinical examination was performed before drawing the samples and they were analysed by serological assessment of Immunoglobulin G (IgG) for COVID-19, Enzyme-Linked Immunosorbent Assay (ELISA), using EUROIMMUN kit {specificity of the Anti-SARS-CoV-2 ELISA (IgG) amounted to 99.6%} from serum samples. The standardised sensitivity of the kit was predetermined in reference to the kit manufacturer’s instructions. The cut-off value:

• ≥0.8- Positive
• >1.1- Strong positive.

Statistical Analysis

The data were entered in MS Excel and double-checked to avoid any error in the data entry. Epi info software 7, downloaded from the WHO site was used to manage and analyse the data. The hypothesis testing was done using Chi-squared test and the data were carefully described by tabular as well as graphical means.


Total 714 HCWs volunteered for sero-survey. Amongst them mean age was 35.30 with a standard deviation of 11.79. Out of 714 people, 54.8% (391/714) were male and 45.2% (323/714) were female. Among the HCWs, there were 426 physicians, 148 nursing staffs, 97 ward staffs and cleaners and 22 technicians (Table/Fig 1). It is also noted that 97 out of the total 714 (13.85%) have less than undergraduate level qualification. In addition, 513 HCWs were posted in COVID-19- designated duties and 201 HCWs did not have any COVID-19 duties (Table/Fig 1).

A total of 91 (12.4%) HCWs out of the total 714 were IgG positive for COVID-19 irrespective of the duties assigned (Table/Fig 2). Among them, 44 were not assigned any COVID-19 duties. The distribution of positive and negative IgG levels was further tabulated based on whether or not the HCW was posted in COVID-19 duty (Table/Fig 3). In this serosurvey, 21.89% people among HCWs not involved in COVID-19 designated duty were positive for IgG, which was much higher than the persons doing COVID-19 designated duties (9.16%) which were statistically significant.

In the study, it was evident that not a great amount of positivity was found from the highly COVID-19 exposed areas. 22% positivity was found in people who were not indulged in COVID-19 direct exposure compared to 18.59% further stratified into 9.16% among people doing COVID-19 ward duty, 9.43% among people doing COVID-19 Critical Care Unit (CCU) duty. Moreover the duration of COVID-19 duties was not significantly related to IgG positivity.

Maximum positivity rate/seroprevalence for IgG was found to be among ward staff and cleaners (29, 29.9%) (p-value<0.0001) when compared to other groups (Table/Fig 4),(Table/Fig 5). In this survey, seroprevalence was least amongst nursing staffs with 5.41% seroprevalence (8/148); among doctor’s it was 9.62% (41/426); most interestingly we stratified the others group further and among ward boys and cleaners this prevalence was found to be 29.90% (29/97) being the highest. When the population was analysed as per educational qualification into postgraduate/graduate/less than graduate strata persons belonging to ‘less than undergraduate’ group had maximum incidence of sero-positivity with 29.9% (29/97).


It is of utmost importance to look out for the ‘trojan horse’ that is the asymptomatic HCWs who can potentially spread the disease in the hospital set-up and subsequently, outside, in the community. Strictly adhering to infection prevention and control measures like mask-wearing, using protective gears, and frequent surveillance testing can prevent spread.

In this study sample, 391 subjects were male and 323 were females. Positivity among male HCWs was 63/391 (16.11%) and females 28/323 (8.67%). A similar study by Wattal C et al., involving 1033 HCWs shows that seropositivity was significantly lower among females 114/545 (20.9%) than among males 153/488 (31.4%), (p-value <0.001) (16).

In the same study by Wattal C et al., the seropositivity among doctors 16/240 (6.7%, p-value<0.001), the technical staff was 12/89 (13.4%, p-value <0.001), and nurses were 53/297 (17.8%, p-value <0.001). Seroprevalence in the former was much lower than that seen in security staff 32/53 (60.4%, p-value <0.001), sanitary workers 49/89 (55.42%, p-value <0.001), and ward boys 28/68 (41.2%, p-value <0.001) (16). The present study resonates with their study. It shows the least seropositivity among nursing staff with seroprevalence 8/148 (5.41%) and doctors with 41/426 (9.62%) seroprevalence. The highest was noted in ward boys and cleaners, 29/97(29.90%). This may be attributable to the difference in educational qualification and awareness about COVID-19 infection prevention and control guidelines. This study reveals people belonging to the ‘less than undergraduate’ group had a maximum incidence of seropositivity 30with 29/97 (29.90%). In this serosurvey, 44/201 (21.89%) HCWs not involved in COVID-19-designated duty tested positive for IgG, and only 47/513 (9.16%) tested positive among HCWs doing COVID-19-designated duty.

A similar finding was noted in a study by Khan MS et al., which showed HCWs who had worked at a dedicated COVID-19 hospital had a lower seroprevalence of 0.6% (95% CI, 0.2%-1.9%) and a lower multivariate-adjusted risk of seropositivity (odds ratio, 0.21; 95% CI, 0.06-0.66) compared to 2.8% seen in HCWs doing non COVID-19 duty (17). Also, all 140 samples collected from ICU/HAU and emergency at Royal Columbian Hospital were negative for COVID-19 in a study done by Deady B et al., (18).

In the study carried out by Olayanju O et al., in Nigeria 60/133 (45.1%) HCWs were seropositive for SARS-CoV-2. Among them 25/55 (45.0%) doctors, 8/33 (23.3%) nurses, 3/19 (16.7%) health assistants, 1/18 (6.7%) laboratory scientists and technicians, and 1/8 (8.3%) non medical staff. This discrepancy in Nigeria is most likely due to the lack of protective gears and minimum surveillance provided to the HCWs who attended COVID-19 positive patients at the peak of the pandemic (19). Data concerning COVID-19-infected asymptomatic HCWs is limited. Hence, this study delves into this aspect and also resurfaces other studies to highlight one of the vital modes of community spread of the infection that is otherwise generally disregarded.


The sample size was small and taken from a single tertiary care centre. Hence, the results cannot be generalised. The asymptomatic COVID-19 positive cases were not followed-up in the next two weeks. The patients who developed symptoms in those days were erroneously categorised as asymptomatic patients. There was no provision for separating the symptomatic and asymptomatic patients suffering from COVID-19 in wards. So, authors could not judge the transmission probability from an asymptotic patient exposure. Also, this study measured the IgG levels only which develop almost two weeks after an active infection. Thus, it limits authors ability to segregate the asymptomatic HCWs as a possible carrier of the disease early on.


This serosurvey has documented high seroprevalence among ward boys as well as cleaners and low seroprevalence among nurses and doctors. The knowledge of this disease as a droplet-borne infection, awareness, and education regarding adherence to strict precaution measures like wearing masks, protective gear, and hand hygiene at all times is the key to infection prevention and control. COVID-19 designated duties and hours spent in COVID-19 patient care are not significantly associated with disease transmission. Early detection of disease by frequent facility-based surveillance is required to prevent cross-infection in the hospital and super-spread of infection in the community.


Authors would like to thank the administration of Medical College and Hospital, Kolkata, the whole of Department of General Medicine, Department of Biochemistry for their support.


Gostic K, Gomez AC, Mummah RO, Kucharski AJ, Lloyd-Smith JO. Estimated effectiveness of symptom and risk screening to prevent the spread of COVID-19. Elife. 2020;9:e55570. Doi: 10.7554/eLife.55570. [crossref]
World Health Organization. Pneumonia of unknown cause- China. January 5, 2020 (
World Health Organization. Novel Coronavirus- China. January 12, 2020 (
Zhu N, Zhang D, Wang W, Li X, Yang B, Song J, et al. A novel coronavirus from patients with pneumonia in China, 2019. N Engl J Med. 2020;382:727-33. [crossref] [PubMed]
Centers for Disease Control and Prevention. Symptoms of coronavirus disease 2019 (COVID-19); 2020 (https://www.cdc .gov/coronavirus/2019-ncov/about/symptoms.html).
World Health Organization. Coronavirus disease 2019 (COVID-19): Weekly epidemiological update. October 12, 2020 (
World Health Organization. Rolling updates on coronavirus disease (COVID-19). 2020 (
West Bengal Health and Family Welfare Department. 2019 nCoV bulletin as on 25th 467 September 2021. 2021 (
Wu JT, Leung K, Leung GM. Nowcasting and forecasting the potential domestic and international spread of the 2019-nCoV outbreak originating in Wuhan, China: A modelling study. Lancet. 2020;395(10225):689-97. Doi: 10.1016/S0140-6736(20)30260-9. [crossref]
Chen J. Pathogenicity and transmissibility of 2019-nCoV-A quick overview and comparison with otheremerging viruses. Microbes Infect. 2020;22(2):69-71. Doi: 10.1016/j.micinf.2020.01.004. [crossref] [PubMed]
Mahase E. Coronavirus COVID-19 has killed more people than SARS and MERS combined, despite lower casefatality rate. BMJ. 2020;368:m641. Doi: 10.1136/bmj.m641. [crossref] [PubMed]
Li Q, Guan X, Wu P, Wang X, Zhou L, Tong Y, et al. Early transmission dynamics inWuhan, China, of novel corona virus-infected pneumonia. N Engl J Med. 2020;382(13):1199-207. Doi: 10.1056/NEJMoa2001316. [crossref] [PubMed]
Zou L, Ruan F, Huang M, Liang L, Huang H, Hong Z, et al. SARS-CoV-2 viral load in upper respiratory specimens of infected patients. N Engl J Med. 2020;382(12):1177-79. Doi: 10.1056/NEJMc2001737. [crossref] [PubMed]
Gao Z, Xu Y, Sun C, Wang X, Guo Y, Qiu S, et al. A systematic review of asymptomatic infections with COVID-19. Journal of Microbiology, Immunology and Infection. 2021;54(1):12-16. ISSN 1684-1182. [crossref] [PubMed]
Cho SY, Kang JM, Ha YE, Park GE, Lee JY, Ko JH, et al. MERS-CoV outbreak following a single patient exposure in an emergency room in South Korea: An epidemiological outbreak study. Lancet. 2016;388(10048):994-1001. [crossref]
Wattal C, Oberoi JK, Goel N, Datta S, Raveendran R, Rao BK, et al. A crosssectional study of SARS-CoV-2 seroprevalence among asymptomatic healthcare workers in a tertiary healthcare centre: Assessing the impact of PPE guidelines. Indian J Med Microbiol. 2021;39(4):528-33. [crossref] [PubMed]
Khan MS, Haq I, Qurieshi MA, Majid S, Bhat AA, Qazi TB, et al. SARS-CoV-2 Seroprevalence among healthcare workers by workplace exposure risk in Kashmir, India. J Hosp Med. 2021;16(5):274-81. [crossref] [PubMed]
Deady B, Ivkov V, Taylor JA, Tun M, Gillis J, Tisseur A, et al. Point prevalence of asymptomatic COVID-19-positive hospital personnel on high-risk wards in a large urban hospital in British Columbia. BCMJ. 2021;63(7):282-84. Clinical Articles, COVID-19.
Olayanju O, Bamidele O, Edem F, Eseile B, Amoo A, Nwaokenye J, et al. SARSCoV-2 seropositivity in asymptomatic frontline health workers in Ibadan, Nigeria. The American Journal of Tropical Medicine and Hygiene. 2021;104(1):91-94. [crossref] [PubMed]

DOI and Others

DOI: 10.7860/JCDR/2022/52612.16260

Date of Submission: Sep 29, 2021
Date of Peer Review: Dec 23, 2021
Date of Acceptance: Feb 04, 2022
Date of Publishing: Apr 01, 2022

• Financial or Other Competing Interests: None
• Was Ethics Committee Approval obtained for this study? Yes
• Was informed consent obtained from the subjects involved in the study? Yes
• For any images presented appropriate consent has been obtained from the subjects. No

• Plagiarism X-checker: Sep 30, 2021
• Manual Googling: Jan 22, 2022
• iThenticate Software: Jan 26, 2022 (11%)

ETYMOLOGY: Author Origin

JCDR is now Monthly and more widely Indexed .
  • Emerging Sources Citation Index (Web of Science, thomsonreuters)
  • Index Copernicus ICV 2017: 134.54
  • Academic Search Complete Database
  • Directory of Open Access Journals (DOAJ)
  • Embase
  • EBSCOhost
  • Google Scholar
  • HINARI Access to Research in Health Programme
  • Indian Science Abstracts (ISA)
  • Journal seek Database
  • Google
  • Popline (reproductive health literature)