COVID-19 Positivity Rate among the Students and Faculty of RajarajeswariDental College & Hospital, Bangalore During the Peak of Second Wave afterTwo Standard Doses of Covishield Vaccine - A Cross-Sectional Survey

Introduction

The COVID-19 is an ongoing global pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The novel coronavirus was first identified in Wuhan, China, in December 2019. In spite of strict lockdown in Wuhan and other cities of Hubei province, they failed to contain the outbreak, and it spread to other parts of mainland China and around the world. The World Health Organization (WHO) declared the outbreak, as a Public Health Emergency of International Concern on 30th January 2020, and as a pandemic on 11th March 2020. Coronaviruses (CoVs) are positivesense single-stranded RNA viruses that cause diseases in humans and animals. The CoVs belongs to the family Coronaviridae that consists of variant strains like alpha, beta, delta, and gamma coronaviruses with large RNA genomes and a unique replication method. Since 2021, variants of the virus have resulted in further waves in several countries, with the Delta, and Beta variants being the most virulent. Globally, as of October 2021, around 241,886,635 confirmed cases of COVID-19 and 4,919,755 deaths have been reported to WHO, and a total of 6,655,399,359 vaccine doses have been administered, making it one of the deadliest pandemics in history.^1,2

As the COVID-19 pandemic continued to spread at an alarming rate globally, there has been a long impact on health, education and economy, including substantial mortality among elderly population, especially those with pre-existing comorbidities. Various vaccines were developed globally with international standards. Administration of safe, effective and affordable vaccines against COVID-19 is of paramount importance in controlling the pandemic crisis and restoring immense human suffering, substantial economic loss, and social mayhem to normalcy. The different strategies for vaccine development against COVID-19 can be divided into the following categories-DNA-based vaccines, RNA-based vaccines, non-replicating viral vector (NRVV), replicating viral vector (RVV), inactivated vaccines (IAcV), live-attenuated vaccines (LAVs), and protein subunit.^3,4,5 The National regulatory authorities have granted emergency use authorizations for twentytwo COVID-19 vaccines. India, being the second largest country in terms of population and number of cases, had more than twelve vaccination trials and developments going on during that period. In January 2021, two vaccines against COVID-19, COVISHIELD™ (AstraZeneca) and COVAXINTM (Bharat Biotech) were accorded emergency use approval in India. COVISHIELD™ vaccine, the Oxford-AstraZeneca vaccine manufactured by Serum Institute of India, was the first vaccine which the government gave permission to be administered among all the health care workers irrespective of their age group.^6-9

COVISHIELD™ (ChAdOx1 nCoV-19) is an adenovirus vector-non-replicating virus vaccine carrying recombinant spike protein of SARS-CoV-2. AZD1222 (ChAdOx1) is the research name. It is a Non-Replicating Viral Vector type vaccine. COVISHIELD™ is a monovalent vaccine composed of a single recombinant, replication-deficient chimpanzee adenovirus (ChAdOx1) vector encoding the S glycoprotein of SARS-CoV-2. Following administration, the S glycoprotein of SARSCoV-2 is expressed locally stimulating neutralizing antibody and cellular immune responses.

Determining the effectiveness of this vaccination among the Indian population was necessary. To evaluate the efficacy and effectiveness of the COVISHIELD™ (ChAdOx1 nCoV- 19) vaccination, there was a need to study the occurrence of COVID-19 in vaccinated individuals. Therefore, the aim of this study was to evaluate the COVID-19 positivity rate among the students and faculty of Rajarajeswari Dental College & Hospital, Bengaluru during the peak of second wave after administering two standard doses of COVISHIELD™ vaccine.

Methods

A questionnaire study was designed and executed at Rajarajeswari Dental College & Hospital on 25th May 2021. This study included all the staff and students who were vaccinated with two standard doses of COVISHIELD™ vaccine. Non vaccinated subjects and subjects vaccinated with only first dose of the vaccine were excluded from the study.

This study consisted of subjects in the age group of 18- 65 years. Rajarajeswari Medical College & Hospital was one of the vaccination centres in Bengaluru, Karnataka. As per Government advisory and Ministry of Health and Family welfare, the advocated time gap between the first and second dose was 4-6 weeks.

All the health care workers of Rajarajeswari Dental College & Hospital got vaccinated at Rajarajeswari Medical College & Hospital. The first standard dose of COVISHIELD™ vaccine was administered on 8th and 9th of February 2021 and the second standard dose of COVISHIELD™ vaccine was administered on 19th and 20th March 2021 to all the health care workers of the institution. The gap between first and second standard doses was 5 weeks and 4 days.

COVISHIELD™ is a colourless to slightly brown, clear to slightly opaque solution. The vaccine was inspected visually prior to administration and discarded if particulate matter or differences in the described appearance were observed. Each vaccine dose of 0.5 ml was withdrawn into a syringe for injection to be administered intramuscularly. A separate sterile needle and syringe for each individual was used. It was normal for liquid to remain in the vial after withdrawing the final dose. The vaccine does not contain any preservative. Aseptic technique was followed during withdrawing the dose for administration. Once opened, multi-dose vials were used as soon as practically possible and within six hours when kept between +2ºC and +25ºC. Any unused vaccine from the opened vial was discarded. To facilitate the traceability of the vaccine, the name and the batch number of the administered product was recorded for each recipient. COVISHIELD™ contains genetically modified organisms (GMOs). Any unused vaccine or waste material was disposed in accordance with local requirements. Spills were disinfected with an appropriate antiviral hydrogen peroxide-based disinfectants.¹⁰ All the vaccinated health care workers were kept under observation during the post vaccine period for about an hour to monitor any adverse effects of vaccine. No adverse effects were observed.

The questionnaire was designed and distributed four weeks post the second standard dose of COVISHIELD™ vaccination. Powell stated that immunity improves by about 50% after the 1st dose of COVISHIELD™ vaccination. It is only about two weeks after taking the 2nd dose of COVISHIELD™ vaccination, the protection of vaccine against symptomatic COVID-19 rises to 95%.¹¹

The study period coincided with the peak of second wave in Karnataka. The questionnaire was validated. The questionnaire was distributed to all the dental undergraduates, post-graduates, teaching and non-teaching staff of Rajarajeswari Dental College & Hospital. It was distributed as google form to all the study subjects. Since some of the non-teaching staff were not aware on how to fill google forms, hard copies were distributed. The non-teaching staff who could not comprehend the google forms were subjected to telephonic interview.

The medium of instruction of the questionnaire was English. The questionnaire had two parts, the first part was to record the general information of participant which included- Name, E-mail address, age, gender, and the second part consisted a total of twelve questions with sub questions. To avoid bias, most of the questions were framed in such a way that only ‘yes’ or ‘no’ responses can be provided as answers.

This study consisted of a total of 650 subjects, including 368 undergraduates, 112 post graduates, 73 teaching staff, and 97 non-teaching staff (Table 1, Figure 1).

The obtained data was subjected to statistical analysis using Statistical Package for Social Sciences (SPSS) for windows version 22.0 released 2013, Armonk, NY: IBM Corp. Descriptive statistics was performed using the expression of responses for the study questionnaire using number and frequency. Chi square test was used to compare the responses for the study questionnaire between different study groups and p value, the level of significance for the statistical analysis was set at p<0.05.

Results

Six hundred and fifty subjects were screened for the study, out of which 43 subjects were excluded as they were not vaccinated with two standard doses of COVISHIELD™ vaccine. Hence a total of 607 subjects were included in the study (Table 2, Figure 2).

Age of the subjects ranged from 18 years to 65 years (Table 3, Figure 3).Out of 650 subjects, 479 were females and 17 were males (Table 4, Figure 4). Out of total 607 subjects who took vaccination, 32 subjects (5.27%) were tested COVID-19 positive and the rest 575 subjects (94.7%) were found to be COVID-19 negative after taking two standard doses of COVISHIELD™ vaccine (Table 5, Figure 5).

Out of the 32 subjects who were tested positive for COVID-19 after two doses of COVISHIELD™ vaccine, only one subject showed a temperature above 101degree Fahrenheit. Twenty two subjects showed temperature ranging from 99-degree Fahrenheit to 101degree Fahrenheit. Fifteen subjects had mild to moderate cold and cough, eight subjects had throat pain, and 11 subjects had body ache.

From among the 32 subjects, only four subjects had breathlessness, four subjects showed low oxygen saturation, out of which one subject showed a low SpO2 measuring 65% and the rest three subjects showed SpO2 ranging from 90-95%. Two subjects complained having loss of taste and five experienced loss of smell. Two subjects reported having mild diarrhoea.

Tests which were done to diagnose COVID-19 were Rapid Antigen and RTPCR. Out of the 32 subjects, three subjects were diagnosed to be COVID-19 positive by only Rapid Antigen test. Seven subjects underwent both RTPCR and Rapid Antigen Test. Twenty two subjects underwent only RTPCR test. Five subjects who tested positive for COVID-19 underwent HRCT examination, out of which only one subject showed CO-RADS score of 4. Blood investigations were done for two subjects.

Among the 32 subjects who were tested positive for COVID-19, only one subject was hospitalised and had required oxygen support. Rest of the 31 subjects had mild to moderate symptoms requiring only home quarantine.

Thirteen out of 32 subjects were primary contacts of family members who were tested positive. The primary contacts of the health care workers who turned COVID-19 positive were also tracked but no one reported to be COVID-19 positive being a primary contact.

Discussion

Vaccines play an important role in limiting spread of novel coronavirus, decrease the severity of disease and prevent death. India started vaccination programme on 16th January 2021, and the initial participants in vaccination drive were the healthcare workers. Our institution started the vaccination programme for all the staff and students on 8th February 2021 and schedule of second dose was completed on 20th March 2021.

COVISHIELD™ (AstraZeneca) is a vaccine carrying spike proteins of COVID-19 non-replicating adenovirus, claimed to have efficacy of 74% in phase II and III Trials.^12,13 Vaccine effectiveness refers to how vaccine performs in the wider population.¹⁴ Here we have analysed positivity rate for coronavirus disease among health care providers and front-line workers compared to general population during second wave.

This analysis included data from Rajarajewari Dental College and Hospital, Bengaluru, Karnataka. Study population included students, teaching faculty and nonteaching support staff. Age group of study population ranged between 18-65 years. Six hundred and fifty subjects attended the survey, with forty-three being excluded as they did not complete both the doses of COVISHIELD™ vaccine. The primary objective was to evaluate the effectiveness of COVISHIELD™ vaccine. The team assessed the subjects by evaluating clinical symptoms, presenting symptoms, severity of symptoms as per MoHFW criteria. Patient reported outcome measures provide valuable information about the effectiveness and ensure the clinical data observations.¹⁵

Vaccines efficacy was measured based on how many people who got vaccinated developed the outcome that is COVID-19.¹⁶ Vaccine effectiveness studies published by Indian Armed Forces has shown similar results of 91.8 to 94.6% (corrected effectiveness).¹⁷ The second wave of COVID-19 began around February 2021 and peak value reached in mid of April 2021 and the test positivity rate was high in several Indian states.¹⁸ Positivity rate in our study was 5.27% which is very low compared to general population during that time.

The confirmed cases in general population were 2,597,285 with weekly increase of 425,222 cases with weekly change of 19.58% and reported deaths were 23,231 with weekly increase of 8,070 with weekly change of 53.32% as reported by WHO during April 2021 and the reported COVID-19 positivity rate in India was 20% by BCC.^19,20

Thirty-two fully vaccinated subjects were confirmed to be COVID-19 positive even after receiving both the doses of vaccine. Four among them were asymptomatic. Twenty one had mild symptoms and seven had moderate symptoms. One student had severe symptoms requiring hospitalization. Only one case requiring hospitalization was reported in the study population suggesting that vaccination was effective in reducing the severity of symptoms and requirement of hospitalization. Similar observations have been reported in other studies.21,22

Studies have shown better outcomes after vaccination in younger groups compared to older individuals.^13,23 We did not find any difference in the effectiveness of vaccine in younger and older age groups. In this study, three groups of individuals were included - students, teaching staff and non-teaching staff. When data on vaccine effectiveness and severity of symptoms were compared, there was no statistically significant difference between the groups. Hence it can be inferred that vaccine was effective irrespective of age.

Most common presenting feature was fever (n=23) followed by cough and cold (n=15). Eleven of them had body ache. In 31 positive cases, oxygen saturation was maintained between 90-95% except in one case of hospitalization, which was recorded as 65%.

Breathlessness was observed in four individuals who got HRCT done; however, demonstrable CT changes were found for only one of them. Twenty of the infected patients recovered within 10 days and were free of symptoms. Eleven patients recovered within 15 days and only one of them required longer period for complete recovery. Thirteen of the subjects who turned COVID-19 positive were primary contacts of patients infected with SARSCOVID 19. Chen et al. had reported mean recovery time of novel coronavirus disease to be 11 days after involvement of lungs.²⁴ However, it depends on date of presentation to hospital and the care provided.

Limitations of the study were that the follow up time was four months, whereas WHO recommends 12 months follow up period.²⁵ Hence this study results can be considered as interim results. This study has considered existing surveillance data. No serological evaluation of antibodies has been done. Pre-existing systemic conditions have not been considered as comorbidities can influence the outcome. This was a single institutional study. Similar multicentre studies can help in better understanding the effect of vaccination in general population. However, this study can contribute towards the scientific basis of effectiveness of vaccination in health care workers and general population.

Apart from vaccination to health care workers at Rajarajeswari Dental College and Hospital, to stop and control the spread of COVID-19 among the patients and health care workers, awareness must be created by posting visual alert signs and posters at the doorway and in strategic places containing instructions (in appropriate languages) about hand hygiene, respiratory hygiene, and cough etiquette according to the guidelines of National Accreditation Board for Hospitals & Healthcare Providers (NABH).²⁶

Conclusion

Effectiveness of 94.7% for COVISHIELD™ vaccine was observed in this study. Within the limitations of this study, it can be concluded that the positivity rate for coronavirus disease among health care providers and front-line workers zvaccinated with two standard doses of COVISHIELD™ vaccine was 5.27%. This was less compared to the positivity rate reported by BCC among general population of India during the second wave which was 20%. It was observed that vaccination was effective in reducing the severity of symptoms and reduced the requirement of hospitalization of COVID-19 positive patients. This study can contribute towards the scientific basis of effectiveness of vaccination in health care workers and general population.

Conflict of Interest

None.