Journal of Community Medicine & Public Health (ISSN: 2577-2228)

research article

Exploratory Sero Prevalence of SARS-CoV-2 (COVID-19) among Health Care Professionals in Department of Community Medicine & School of Public Health (PGIMER, Chandigarh): An Exploratory Study

Vivek Sagar, Gurwinder Kaur, Aditi Sharma, Anuradha Nadda, Rupinder Khurana, Arun Aggarwal*

Department of Community Medicine and School of Public Health, PGIMER, Chandigarh, India

*Corresponding author: Arun Aggarwal, Department of Community Medicine and School of Public Health, PGIMER, Chandigarh, India

Received Date: 01 April, 2021; Accepted Date: 20 April, 2021; Published Date: 26 April, 2021

Abstract

The safety of Healthcare Workers (HCWs) against SARS-CoV-2 transmission is an important aspect of managing the COVID-19 pandemic. Depending upon the level of sero prevalence of infection, public health interventions can be implemented for prevention and control of the disease. Therefore, the present study was designed to estimate the level of SARS-CoV-2 IgG antibodies among healthcare professionals in the Department of Community Medicine & School of Public Health PGIMER Chandigarh. The participants were selected by simple random sampling method. Collected serum samples were tested for the detection of IgG Antibodies against SARS-CoV-2 by using ELISA kit (Zydus Diagnostics) and results were analysed as per manufacturer’s instructions. Out of total 56 participants, equal proportion of males and females participants i.e. 28 participated in study. Among these 7 participants showed the presence of IgG antibodies. Therefore, the exploratory seroprevalence of 12.5% was observed among healthcare professionals of Community Medicine and School of Public Health, PGIMER, Chandigarh, which is higher in comparison to seroprevalence, reported in general population.

Keywords

ELISA; IgG antibodies; COVID-19; SARS-CoV-2; Health care professional

Introduction

The Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) known as coronavirus disease 2019 (COVID-19) had emerged from the Wuhan, Hubei province, China in December 2019 and was declared as pandemic by the World Health Organization (WHO) on 11th March 2020 [1]. Recent reports from WHO has shown 119,603,761confirmed cases of COVID-19, including 2,649,722 deaths, worldwide [2].

Community transmission is expected to rise from individuals who have no symptoms (asymptomatic). As a result, there will be an ongoing need for front-line health-care workers in patient-facing roles. Front-line health-care workers are at high risk of getting the infection as they have close proximity to patients with SARS-CoV-2, which may contribute to further spread of the disease [3]. Initial estimates suggest that front-line health-care workers could account for 10-20% of all diagnosis [4,5]. According to Ko, JH, et al., patients with subclinical infections may be missed out or may remain undiagnosed by the current symptom-based screening strategy [6]. Recent published data have shown that asymptomatic and subclinical COVID-19 patients develop detectable amounts of anti-SARS-CoV-2 antibodies that can be detected by serological tests [6]. ELISA tests have been recommended for sero-surveys to understand the proportion of population exposed to the infection, including asymptomatic individuals [7]. A study conducted by Tanu, et al. in Mumbai (India) documented that the prevalence of infection in asymptomatic HCWs was 4.3% and 70% among asymptomatic and symptomatic HCWs respectively [8]. The safety of Healthcare Workers (HCWs) against SARS-CoV-2 transmission is an important aspect of managing the COVID-19 pandemic [9]. Depending upon the level of sero prevalence of infection, public health interventions can be implemented for prevention and control of the disease. Therefore the present study has been designed to estimate the level SARS-CoV-2 IgG Antibodies among healthcare professionals in the Department of Community Medicine & School of Public Health PGIMER Chandigarh.

Methodology

Ethical clearance: Ethical clearance for the present study was taken from Institute Ethics committee.

Study type: This is an Exploratory Study.

Study population

Study included Staff members of Department of Community Medicine & School of Public Health (Faculty, Junior/Senior Demonstrators, Junior/Senior Residents, Students/Research Staff and Office Staff and Sanitation Staff) (Table 1).

Sampling method

Total of 148 staff members were present in the concerned department. Based on prevalence of 6% the sample size of 55 participants was calculated [3]. The selected population (55 participants) was further divided into seven groups. Each group consisted of 8 participants selected by simple random sampling method (Table 1). Demographic details were taken from all the participants.

Collection of Samples

3 ml of venous blood sample was collected in a plain vial after taking the consent from the participant. Serum was separated by centrifuging the whole blood at 1500 rpm for 10 minutes. The vial containing serum sample was labelled and stored at -20°C till further use. The samples were then used for the detection of IgG antibodies by using ELISA Covid KavachTM (Zydus Diagnostics) kit. Analysis of results was done as per guidelines given in kit brochure.

Results

The present study comprised of 56 participants, 28 males and 28 females (Figure 1) with age group ranging from 18-58 years. Out of 56, seven participants had IgG antibodies in their serum samples (Figure 2) indicating seroprevalence of 12.5% in health care professionals of Department of Community Medicine & School of Public Health PGIMER Chandigarh.

Out of 7 positive participants, three had history of COVID-19 infection in the past and were positive with RT PCR. Whereas rest of the positive participants were either had contact with COVID-19 positive patients or had symptoms similar to COVID-19 (Table 2). This result indicates that few patients might go unnoticed due to apprehensions of getting tested for COVID-19. Similarly, 5 participants had comparable higher OD value (above 0.20) but less than cut-off (0.29) value (Table 3). History of these participants revealed that all these had a contact history with COVID-19 patients and might not have followed COVID-19 safety guidelines of mask and social distancing.

History of participants with negative IgG value but having contact history with COVID-19 patients are shown in (Table 4). Maximum participants followed safety guidelines when they came in contact with COVID-19 positive patients. In other words, all IgG negative participants with contact history with COVID-19 patients, either followed strict mask or social distancing. This may be reason that they remain safe from COVID-19 as indicated with IgG results.

Among all 7 groups, maximum number of positivity was observed in Group V which includes MSW, PHNO and MPHW staff (Figure 3).

Out of total 56 participants in this study, total 5 (9%) stated COVID-19 positivity with PCR, out of which 3 came out positive for IgG antibodies, 1 was close to cut-off value and 1 came out to be negative indicating the good co-relation of RT PCR results with IgG antibody titre results.

Discussion

In this study seroprevalence 12.5% observed and it was comparable to reported by Goenka, et al. among health care workers which were 11.94% [10]. Similar studies on health care workers from other countries reported a percentage of as low as 0% in Malaysia [11], 4% in Denmark [12], 1.06%-13.7% in the United States of America, [13,14], 6.4% in Belgium [15] 9.3% in Spain [16], 10.6% in the United Kingdom (UK) [17,18] to as high as 17.14% in China [19,20]. This difference may be correlated to the period of study, the frequency of COVID-19 in the local community, and hospital policy in terms of triage, social distancing, hand sanitization, use of PPE. Singhal, et al. reported 4.3 % prevalence of infection in asymptomatic HCWs and 70% in previously symptomatic untested HCWs [8]. Seroprevalence among health care workers was high in comparison to general population [21].

Some of the other studies have also reported none/rare infection in the HCWs directly involved in the care of COVID-19 patients [22]. This can possibly be attributed to better Personal Protective Equipment (PPE) and heightened caution of HCWs in COVID-19 areas.

Similarly as per this study, previous studies also report higher positivity rates in HCWs with symptoms as compared to asymptomatic HCW [23]. Therefore, testing of symptomatic HCWs will be preferred than asymptomatic HCW.

The accuracy of antibody tests in COVID-19 has yet debateable [24]. Various kits are available which differ from each other, and local validation of the kits is recommended [25]. It is also known that the extent of the antibody response depends on the severity of infection; patients with asymptomatic infections/ mild infections may not mount a measurable antibody response [26]. So our results with high OD value but less than cut value of 5 participants may be due to mild infections. Hence, these antibody tests can underestimate the infection rate in those tested. Conversely, cross-reactivity with other coronaviruses may lead to false-positive results [25].

The other important question is whether HCWs with previous infection or measurable antibodies are immune to reinfections and hence be deployed in high-risk areas. There is evidence from animal studies that previous infection with COVID-19 protects against reinfection [27]. However, questions relating to the longevity of the immune response, the level of antibodies required for protection and the relationship between binding antibodies (measured by commercial tests) and neutralising antibodies that give protection remain unanswered [25]. Besides, anecdotal cases of relapse/ reinfection of SARS-CoV-2 have also been described [28].

Baveja, et al. first studied on seroprevalence of SARS-CoV-2 among HCWs from India, where the COVID-19 pandemic is yet to peak [29]. In his study they have shown that 6.9% of the health care staff had antibody against SARS-CoV-2, with IgM antibody among 4.8% and IgG among 4.1% [29].

IgM antibodies generally rise to become detectable in approximately 5-7 days after the initial onset of symptoms and remain so for 14-21 days. About day 14, after symptom onset, IgG will rise above detection levels, peaking around or after clinical recovery and will remain detectable for months or even years after the resolution of infection [30].

Earlier studies on COVID-19 among HCWs have focused on antigen testing among symptomatic individuals or their contacts. In one of the study done among 316 HCW’s of University Hospital Germany showed only 1.6%, HCW’s having IgG antibodies [31]. A study among HCWs in Spain reported 31.6% of workers to be IgG positive, whereas, in a multi-hospital study in Lombardy, Italy, 3 to 43% of the health care and administrative staff were positive for IgG [32,33].

Sandri, et al. from Italy have reported significantly higher seroprevalence among females, which we did not find in our study. They also reported that middle-aged men (not women) were more likely to induce an antibody response [33].

Another study by Steensels, et al. in Belgium also provided an estimate of 6.4% of the hospital staff having IgG antibodies which were not associated with contact with COVID-19 patients in the hospitals but associated with household contact of COVID-19 patient [34].

A large hospital-based study in Syria showed high compliance with protective measures by hospital staff which was due to the training provided and was more among doctors and nurses and lower among pharmacists [35]. Even our study also showed that compliance with mask and social distancing can prevent from getting infected to large extends [36].

So in all, large scale seroprevalence studies are important to be conducted in future to estimate the percentage of population who have got exposure of COVID-19 infection. This information would be important for implementation of vaccination strategy for whole population.

Conclusions

Exploratory seroprevalence of 12.5% among healthcare Professionals of Community Medicine and School of Public Health, PGIMER, Chandigarh, was comparable to earlier reports of health care workers and was higher in comparison to general population of India. In our study we reported higher rates of infection in the MSW, PHNO and MPHW as compared to other staff. Mask along with social distancing is effective approach to prevent the transmission.

The small sample size is the limitations of this study. There is need of larger serosurveys in HCWs and comparing them to the general population will help in further defining the epidemiology of the illness. So more studies needs to be conducted in future by taking more participants.

Acknowledgement

Special thanks to the staffs of the Department of Community Medicine & School of Public Health, PGIMER, Chandigarh for participating in study and also for their technical and administrative support for this study. We would to like thank Zydus Cadila for providing the testing kit.

Ethical Approval

Took Ethical clearance from Institutional Ethical Committee (INT/IEC/2021/SPL-122).

 
Figure 1: Pie chart showing male vs female ratio.


Figure 2: Showing number of IgG positive, borderline and negative participants.


Figure 3: Graph showing group wise positivity for IgG antibody.

S. No

Group No.

Category

No. of Staff Members

1

Group I

Faculty

18

2

Group II

Ph.D. Students

25

3

Group III

Junior & Senior Residents

19

4

Group IV

BPH Students

22

5

Group V

MSW, PHNO, MPHW

18

6

Group VI

SD, JD, SS, LT, SA, HA

20

7

Group VII

MPH Students

26

Total

 

 

148

BPH: Bachelor in Public Health; MSW: Medical Social Worker; PHNO: Public Health Nursing Officer; MPHW: Multipurpose Health Worker; SD: Senior Demonstrator; JD: Junior Demonstrator; SS: Secretarial Staff; LT: Laboratory Technician; SA: Sanitary Attendant; HA: Hospital Attendant


Table 1: Details of Groups of Participants.

S. No

Name

COVID-19 history (by Participant)

COVID-19 test

In Contact with COVID-19 Patient

Possibility of contact with COVID-19 Positive patient

Symptom

Without Mask

Without Social Distancing

1

Participant 19

Yes

Done (+ve)

Not known

Not Applicable

Not Applicable

Yes

2

Participant 41

Yes

Done (+ve)

Yes

Yes

Yes

Yes

3

Participant 08

No

Done (-ve)

Yes

No

No

Yes

4

Participant 46

No

Done (-ve)

Yes

Yes

Yes

Yes

5

Participant 47

Yes

Done (+ve)

Yes

Yes

Yes

Yes

6

Participant 54

No

Not done

Not known

Not Applicable

Not Applicable

Yes

7

Participant 56

No

Done (-ve)

Yes

Yes

Yes

Yes


Table 2: Details of IgG positive participants.

S. No

Name

COVID-19 history (by Participant)

In Contact with COVID Patient

Contact with COVID Positive patient

 

Symptom

Without Mask

Without Social Distancing

1

Participant 40

No

Yes

Yes

Yes

No

2

Participant 29

No

Not known

Not Applicable

Not Applicable

No

3

Participant 17

No

Yes

No

No

No

4

Participant 14

No

Not known

Not Applicable

Not Applicable

No

5

Participant 20

No

Yes

No

No

Yes


Table 3: History of patients with higher OD value but less than cut off value.

S. No

Name

COVID-19 history (by Participant)

In Contact with COVID Patient

Contact with COVID Positive patient

Symptom

Without Mask

Without Social Distancing

1

Participant 05

No

Yes

No

No

No

2

Participant 07

No

Yes

No

No

No

3

Participant 09

No

Yes

No

No

No

4

Participant 11

No

Yes

Yes

No

Yes

5

Participant 16

No

Yes

Yes

No

No

6

Participant 01

No

Yes

No

No

No

7

Participant 27

No

Yes

No

Yes

Yes

8

Participant 28

No

Yes

No

No

Yes

9

Participant 33

No

Yes

Yes

No

Yes

10

Participant 36

No

Yes

No

No

No

11

Participant 37

Yes

Yes

Yes

Yes

Yes

12

Participant 48

No

Yes

Yes

Yes

Yes


Table 4: History of participants with negative IgG value but having contact history with COVID-19 patients.

References

  1. Li Q, Guan X, Wu P, Wang X, Zhou L, et al. (2020) Early transmission dynamics in Wuhan, China, of novel coronavirus-infected pneumonia. NEJM 382: 1199-1207.
  2. World Health Organization (2020) WHO Coronavirus Disease (COVID-19) Dashboard.
  3. Black JRM, Bailey C, Przewrocka J, Dijkstra KK, Swanton C (2020) COVID-19: the case for health-care worker screening to prevent hospital transmission. Lancet 395: 1418-1420.
  4. CDC COVID-19 Response Team (2020) Characteristics of health care personnel with COVID-19: United States, February 12-April 9, 2020. MMWR Morb Mortal Wkly Rep 69: 477-481.
  5. Lazzerini M, Putoto G (2020) COVID-19 in Italy: momentous decisions and many uncertainties. Lancet Glob Health 8: e641-e642.
  6. Ko JH, Joo EJ, Park SJ, Baek JY, Kim WD, et al. (2020) Neutralizing antibody production in asymptomatic and mild COVID-19 patients, in comparison with pneumonic COVID-19 patients. J Clin Med 9: 2268.
  7. Ko JH, Lee JY, Kim HA, Kang SJ, Baek JY, et al. (2020) Serologic Evaluation of Healthcare Workers Caring for COVID-19 Patients in the Republic of Korea. Front Microbiol.
  8. Singhal T, Shah S, Naik R, Kazi A, Thakkar P (2020) Prevalence of COVID -19 antibodies in healthcare workers at the peak of pandemic in Mumbai, India: A preliminary study. Indian J Med Microbiol 38: 461-463.
  9. https://health.economictimes.indiatimes.com/news/diagnostics/icmr-comes-out-with-list-of-antibody-detection-kits-to-be-used-for-sero-surveys/76212569
  10. Goenka M, Afzalpurkar S, Goenka U, Das SS, Mukherjee M, et al. (2020) Seroprevalence of COVID-19 Amongst Health Care Workers in a Tertiary Care Hospital of a Metropolitan City from India. J Assoc Physicians India 68: 14-19.
  11. Woon YL, Lee YL, Chong YM, Ayub NA, Krishnabahawan SL, et al. (2020) Serology surveillance of anti-SARS-CoV-2 antibodies among asymptomatic healthcare workers in Malaysian healthcare facilities designated for COVID-19 care The Lancet 9: 100123.
  12. Brant-Zawadzki M, Fridman D, Robinson P, Zahn M, Chau C, German R, et al. (2020) SARS-CoV-2 antibody prevalence in health care workers: Preliminary report of a single-center study. PLoS One 15: e0240006.
  13. Iversen K, Bundgaard H, Hasselbalch RB, Kristensen JH, Nielsen PB, et al. Risk of COVID-19 in health-care workers in Denmark: an observational cohort study. Lancet Infect Dis 20: 1401-1408.
  14. Chen Y, Tong X, Wang J, Huang W, Yin S, et al. (2020) High SARS-CoV-2 antibody prevalence among healthcare workers exposed to COVID-19 patients. J Infect 81: 422-426.
  15. Moscola J, Sembajwe G, Jarrett M, Farber B, Chang T, et al. Prevalence of SARS-CoV-2 antibodies in health care personnel in the New York City area. JAMA 324: 893-895.
  16. Garcia-Basteiro AL, Moncunill G, Tortajada M, Vidal M, Guinovart C, et al. (2020) Seroprevalence of antibodies against SARS-CoV-2 among health care workers in a large Spanish reference hospital. Nat Commun 11: 3500.
  17. Pallett SJ, Rayment M, Patel A, Fitzgerald-Smith SAM, Denny SJ, et al. (2020) Point-of-care serological assays for delayed SARS-CoV-2 case identification among health-care workers in the UK: a prospective multicentre cohort study. Lancet Respir Med 8: 885-894.
  18. Eyre DW, Lumley SF, O’Donnell D, Campbell M, Sims E, et al. (2020) Differential occupational risks to healthcare workers from SARS-CoV-2: A prospective observational study. Elife 9: e60675.
  19. Steensels D, Oris E, Coninx L, Nuyens D, Delforge ML, et al. (2020) Hospital-wide SARS-CoV-2 antibody screening in 3056 staff in a tertiary center in Belgium. JAMA 324: 195-197.
  20. Fujita K, Kada S, Kanai O, Hata H, Odagaki T, et al. (2020) Quantitative SARS-CoV-2 Antibody Screening of Healthcare Workers in the Southern Part of Kyoto City During the COVID-19 Pre-pandemic Period. Front Public Health 8: 595348.
  21. Murherkar M, Bhatnagar T, Selvaraju S, Saravanakumar V, Thangaraj JWV, et al. (2021) SARS-CoV-2 antibody seroprevalence in India, August-September, 2020: findings from the second nationwide household serosurvey. Lancet Glob Health 9: e257-e266.
  22. Liu M, Cheng SZ, Xu KW, Yang Y, Zhu QT, et al. (2020) Use of personal protective equipment against coronavirus disease 2019 by healthcare professionals in Wuhan, China: Cross sectional study. BMJ 369: m2195.
  23. Martin C, Montesinos I, Dauby N, Gilles C, Dahma H, et al. (2020) Dynamic of SARS-CoV-2 RT-PCR positivity and seroprevalence among high-risk health care workers and hospital staff. J Hosp Infect 106: 102-106.
  24. Deeks JJ, Dinnes J, Takwoingi Y, Davenport C, Spijker R, et al. (2020) Antibody tests for identification of current and past infection with SARS-CoV-2. Cochrane Database Syst Rev 6: CD013652.
  25. Centers for Disease Control and Prevention (2020) Interim Guidelines for COVID-19 Antibody Testing: Interim Guidelines for COVID-19 Antibody Testing in Clinical and Public Health Settings.
  26. Sethuraman N, Jeremiah SS, Ryo A (2020) Interpreting diagnostic tests for SARS-CoV-2. JAMA 323: 2249-2251.
  27. Deng W, Bao L, Liu J, Xiao C, Liu J, et al. (2020) Primary exposure to SARS-CoV-2 protects against reinfection in rhesus macaques. Science 369: 818-823.
  28. Gousseff M, Penot P, Gallay L, Batisse D, Benech N, et al. (2020) Clinical recurrences of COVID-19 symptoms after recovery: viral relapse, reinfection or inflammatory rebound? J Infect 81: 816-846.
  29. Baveja S, Karnik N, Natraj G, Natkar M, Bakshi A, et al. (2020) Rapid volunteer-based SARS-Cov-2 antibody screening among health care workers of a hospital in Mumbai, India. Indian J Med Sci 72: 148-154.
  30. Jacofsky D, Jacofsky EM, Jacofsky M (2020) Understanding antibody testing for COVID-19. J Arthroplasty 35: S74-S81.
  31. Korth J, Wilde B, Dolff S, Anastasiou OE, Krawczyk A, et al. (2020) SARS-CoV-2-specific antibody detection in healthcare workers in Germany with direct contact to COVID-19 patients. J ClinVirol128: 104437.
  32. Galan I, Velasco M, Casas ML, Goyanes MJ, Rodriguez-Caravaca G, et al. (2020) SARS-cov-2 seroprevalence among all workers in a teaching hospital in Spain: Unmasking the risk. MedRxiv.
  33. Sandri MT, Azzolini E, Torri V, Carloni S, Tedeschi M, et al. (2020) IgG serology in health care and administrative staff populations from 7 hospital representative of different exposures to SARS-CoV-2 in Lombardy, Italy. MedRxiv.
  34. Steensels D, Oris E, Coninx L, Nuyens D, Delforge ML, et al. (2020) Hospital-wide SARS-CoV-2 antibody screening in 3056 staff in a tertiary center in Belgium. JAMA 324: 195-197.
  35. Hessenow R, Hesenow S, Mohammad Y, Hammadyeh AR, Ghattas K, et al. (2020) Evaluation of preventive procedures followed by the medical staff against covid-19 in the Syrian Arab Republic: A cross-sectional study. Indian J Med Sci 72: 49-57.
  36. Maclntyre CR, Wang Q (2020) Physical distancing, face masks, and eye protection for prevention of COVID-19. Lancet 395: 1950-1951.