Persistent health issues, adverse events of significant concern, and effectiveness of COVID-19 vaccination- findings from a real-world cohort study of healthcare workers in north India (preprint)

Background: There is paucity of real-world data on COVID-19 vaccine effectiveness and safety from cohort designs. The current study aimed to evaluate vaccine performance during second wave in India. It also aimed to determine adverse events of significant concern (AESCs), and to ascertain the effect of vaccination on persistent health issues in individuals post COVID-19. Methods: A cohort study was conducted from July-2021 to December-2021 in a tertiary hospital of north India. The primary outcome was vaccine-effectiveness against COVID-19. Secondary outcomes were AESCs, and persistent health issues in those receiving vaccine. Regression analyses were performed to determine risk factors. Results: In 2760 healthcare workers (HCWs) included, 1033 COVID-19 events were reported. Around 6-17% vaccine effectiveness was observed against COVID-19 occurrence. One dose-recipients were at 1.6-times increased risk of COVID-19. Prior SARS-CoV-2 infection was a strong independent protective factor against COVID-19 (aOR 0.66). Full vaccination reduced moderate-severe COVID-19 by 57%. Those with lung disease were at 2.5-times increased risk of moderate-severe COVID-19. AESCs were observed in 1.3% including one case each of myocarditis and severe hypersensitivity. Individuals with hypothyroidism were at 5-times and those receiving vaccine after recovery from COVID-19 were at 3-times higher risk of persistent health issues. Conclusion: COVID-19 vaccination reduced COVID-19 severity but offered marginal protection against occurrence. Relationship of asthma and hypothyroidism with COVID-19 outcomes necessitates focused research. Independent protection of prior SARS-CoV-2 infection was high and persistent health issues were common in individuals receiving vaccine post COVID-19. Recommendations of vaccinating those recovered from COVID-19 need further studies.

Selection of appropriate reference genes for normalization of qRT-PCR based gene expression analysis in SARS-CoV-2, and Covid-associated Mucormycosis infection (preprint)

Selection of reference genes in quantitative PCR is critical to determine accurate and reliable mRNA expression. Despite this knowledge, not a single study has investigated the expression stability of housekeeping genes to determine their suitability to act as reference gene in SARS-CoV-2 or Covid19 associated mucormycosis (CAM) infections. Herein, we address these gaps by investigating the expression stability of nine most commonly used housekeeping genes including TBP, CypA, B2M, 18S, PGC-1α, GUSB, HPRT-1, β-ACTIN and GAPDH in the patients of varying severity (asymptomatic, mild, moderate and severe). We observed significant differences in the expression of candidate genes across the disease spectrum. Next, using various statistical algorithms (delta Ct, Normfinder, Bestkeeper, RefFinder and GeNorm), we observed that CypA demonstrated the most consistent expression across the patients of varying severity and emerged as the most suitable gene in Covid19, and CAM infections. Incidentally, the most commonly used reference gene GAPDH showed maximum variations and found to be the least suitable. Lastly, comparative evaluation of expression of NRF2 is performed following normalization with GAPDH and CypA to highlight the relevance of an appropriate reference gene. Our results reinforce the idea of a selection of housekeeping genes only after validation especially during infections.

Patterns and predictors of COVID-19 occurrence and severity in vaccinated priority groups (preprint)

Background: Varying protection rates have been observed with approved COVID-19 vaccines post-approval, in various real-world studies. However, little data exists on the clinical presentation and risk factors of occurrence and severity of COVID-19 in vaccinated individuals. The aim of the present study is to describe the patterns of presentation of COVID-19 in vaccinated individuals, and to determine the predictors of occurrence of COVID-19 and the predictors of severity in the vaccinated. Methods: : The study is a part of a prospective observational study ongoing since February 2021 in a tertiary teaching and research hospital of northern India. Individuals recruited in this study belong to a high-risk group comprising health care workers and elderly. COVISHIELD, based on ChAdOx1 nCoV-19 platform was the vaccine received by the participants based on policy on allocation.Primary outcomes of the study are the short term and long-term adverse events following immunization (AEFI) with COVID-19 vaccines. Secondary outcomes include the rates of occurrence of COVID-19 and severity of COVID-19. Data on these have been already reported. The clinical presentation, typical and atypical manifestations, time to symptomatic recovery and patterns of post-COVID-19 complaints were analysed in the current study. Logistic regression analysis was performed to predict the risk factors of occurrence of COVID-19 in the vaccinated and the determinants of severe forms of the disease in this group. Findings: 1500 individuals completed at least two month follow up. Of these, 418 developed laboratory confirmed or suspected COVID-19. Fever was the commonest symptom (72%), followed by features of rhinitis (41%) and cough (34%). Nearly 12% individuals had only one symptom or none. Cardiovascular involvement was seen in more than 2% of affected. Time to symptomatic recovery varied from 1-75 days and 11% had post COVID-19 complaints at two month follow up, most common being generalized weakness. Results of regression analysis showed 1.6 times higher odds of contracting the disease in females and young individuals < 40 years of age (P<0.001). Overweight individuals and those receiving only one dose were at 1.4 times and 3 times higher odds of contracting COVID-19 compared to those with normal body mass index and those who were fully vaccinated. Individuals receiving two doses at a gap of < 30 days were at 7 times higher odds of disease acquisition compared to those receiving the second dose at an extended gap of > 60 days (P=0.01).With respect to severity, males and those receiving only one dose each had 3 times higher odds of suffering from moderate to severe COVID-19 compared to females and fully vaccinated. Persons with pre-existing lung disease, such as asthma had 6 times higher odds of suffering from moderate to severe COVID-19 (P=0.024). No association with the occurrence or severity of disease was observed with any other co-morbidity or the use of renin-angiotensin-aldosterone system (RAAS) blockers. Interpretation Sex wise differences exist with respect to occurrence and severity of COVID-19. Two doses of vaccine, compared to one dose provide considerable protection against occurrence as well as severity. Full vaccination with extended dosing interval should be the optimal strategy and should be carried out when the community burden of cases is negligible. Future studies are needed to explore the sex wise differences in the propensity and severity of COVID-19. Further, the risk association of asthma phenotypes with COVID-19 needs to be investigated. Funding: The study received no funding support

A prospective observational safety study on ChAdOx1 nCoV- 19 corona virus vaccine (recombinant) use in healthcare workers- first results from India (preprint)

Vaccines are an important public health measure for tiding over the COVID-19 pandemic. Several vaccines have been approved in different countries for emergency use. In India, two vaccines have been currently approved- COVISHIELD (Serum Institute of India (SII)) which is a recombinant simian adenovirus-based vaccine and COVAXIN (Bharat Biotech) which is an inactivated SARS-CoV-2 vaccine. Our current study provides the first post approval safety data on ChAdOx1 nCoV- 19 corona virus vaccine (recombinant) use in healthcare workers in northern India (n=804). Around one half of vaccinees developed adverse events at any time post vaccination with majority of reactions being mild to moderate in severity. AEFIs were seen in 40% participants after first dose and around 16% participants after second dose. This observed reactogenicity is much less compared to 60-88% reactogenicity rate observed with Oxford-AstraZenecas ChAdOx1 vaccine in the UK based population. Individually, fever, injection site pain and headache were the commonly observed AEFIs. Overall, the frequency of systemic events of severity grade 3 was only 0.5% and is much less than the reported rates for other recombinant adenoviral vaccines. The rate of serious AEFIs in our study was only 0.1% (n=1). There was a possibility of this AEFI being an immunization stress related response. No deaths were reported in the vaccinees in our study during the study period. Reactogenicity rate was observed to decrease with age and was higher in females. On the basis of interim findings of this safety study, it may be interpreted that the ChAdOx1 nCoV-19 corona virus vaccine (recombinant) (COVISHIELD, Serum Institute of India) carries a good safety profile overall.

Of Cross-Immunity, Herd Immunity and Country-Specific Plans: Experiences from COVID-19 in India (preprint)

India has witnessed a high number of COVID-19 cases, but mortality has been quite low, and most cases have been asymptomatic or mild. In early April, we had hypothesized a low COVID-19 mortality in India, based on the concept of cross-immunity. The presence of cross-immunity is presumed to lead to a milder course of disease and allow the time necessary for the development of adaptive immunity by the body to eliminate the virus. Evidence supporting our hypothesis has started showing up. Multiple studies have shown the generation of different T cell subsets and B cells responding to epitopes of viral proteins, especially of the spike protein, as a part of adaptive immunity against SARS-CoV-2. Cross-reactive T-cells have been demonstrated in patients who have been previously exposed to endemic coronaviruses. The interplay of cross-immunity and herd immunity is apparent in the COVID-19 scenario in India by the presence of a large number of asymptomatic or mild cases, a low infection-fatality ratio and a generally flat curve of percentage positivity of cases with respect to total testing, both in periods of strict lock-down and step-wise unlocking. It seems that cross-immunity resulted in faster generation of herd immunity. Although the initial restrictive measures such as lockdown prevented the rapid spread of the outbreak, further extension of such measures and overly expensive ones such as enhanced testing in India will result in a huge burden on the health economics as well as the society. Hence, we propose a restructuring of the health services and approach to COVID-19. The restructured health services should move away from indiscriminate testing, isolation and quarantine, and instead, the emphasis should be on improving facilities for testing and management of only critical COVID cases and the replacement of complete lockdowns by the selective isolation and quarantine of the susceptible persons such as the aged and those with co-morbidities. In the process of describing India-specific plans, we emphasize why the development of country-specific plans for tackling epidemics is important, instead of adopting a “one policy fits all” approach.