Effectiveness of Covid-19 vaccines (CovishieldTM and Covaxin ®) in healthcare workers in Mumbai, India: A retrospective cohort analysis

Effectiveness of interventions to improve vaccine efficacy: a systematic review and meta-analysis

BACKGROUND

Vaccination is a crucial public health intervention that has significantly reduced the incidence of infectious diseases. Vaccine-related interventions refer to strategies implemented to enhance vaccination uptake, coverage, and effectiveness, like modes of delivery, types or dosages. Despite extensive research on vaccine efficacy, a comprehensive analysis of the variability in vaccine effectiveness across different interventions, settings, and populations is limited. This study aims to systematically review and meta-analyze the impact of various Vaccine-Related Interventions (VRIs).

METHODS

This review included 139 randomized controlled trials, cohort, and case-control studies evaluating VRIs from January 2015 to December 2023. The risk of bias was assessed using the ROB-2 and ROBINS-E tools. Statistical analyses were conducted to evaluate overall effect sizes, infection rates, and heterogeneity and subgroup analysis.

RESULTS

Of the 139 studies reviewed, 97 were included in the meta-analysis, comprising approximately 1.4 million participants. Populations across various settings were analyzed, with median vaccinated population sizes for the 1st dose (4598, IQR = 15,749), 2nd dose (6214, IQR = 13,817), and 3rd dose (3508, IQR = 5546). The overall total vaccinated population had a median of 4370 and an IQR of 16,475. The interventions showed a significant positive effect on vaccine efficacy, with an estimated effect size of 0.6432 (95% CI 0.4049 to 0.8815). Heterogeneity was negligible, with Tau2 = 0, I2 = 0.00%, and H2 = 1.00. The Galbraith plot suggested minimal variability. The study utilized ROB-2 and ROBINS-E tools to evaluate bias, with Egger's test (t = - 0.9941, p = 0.3227) confirming no significant publication bias. The funnel plot indicated minimal bias in the included studies.

CONCLUSION

The study supports the effectiveness of vaccine-related interventions in enhancing vaccine efficacy. The negligible heterogeneity and consistent effect sizes across diverse populations and settings provide a robust basis for implementing public health strategies aimed at improving vaccination outcomes.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42024543608.

Revealing COVID-19 breakthrough infection rates among vaccinated individuals at a tertiary care centre in South India

Background and Objectives

The COVID-19 pandemic was mitigated by the rapid development and deployment of vaccines. While vaccines reduce infection severity, breakthrough infections (BTIs) still occur. The CDC defines BTI as a positive SARS-CoV-2 test ≥14 days post-vaccination. This study investigates the occurrence of COVID-19 BTIs at a tertiary care hospital in Puducherry, South India.

Materials and Methods

This retrospective study analysed hospital tested qRT-PCR data of individuals from the ICMR portal (March 2021-March 2022). Demographic and vaccination details were extracted.

Results

Among 8001 tested individuals, 1452 were vaccinated. The BTI rate decreased from 16.6% to 1.2% after the first dose and from 58% to 40% after the second one. Odds ratio indicated a 74% reduction in infection risk for vaccinated individuals compared to unvaccinated. Males had higher infection rates than females, regardless of vaccination status.

Conclusion

Our study demonstrates a higher BTI rate after one vaccine dose compared to two doses. The BTI rate also increased four months post-vaccination, even with two doses, potentially due to waning immunity and the emergence of new variants. Therefore, continued adherence to preventive measures in conjunction with vaccination is crucial for minimizing COVID-19 transmission.

COVID-19 vaccines are effective at preventing symptomatic and severe infection among healthcare workers: A clinical review

Introduction

Health care workers (HCWs) have been at increased risk of infection during the SARS-CoV-2 pandemic and as essential workers have been prioritised for vaccination. Due to increased exposure HCW are considered a predictor of what might happen in the general population, particularly working age adults. This study aims to summarise effect of vaccination in this 'at risk' cohort.

Methods

Ovid MEDLINE and Embase were searched, and 358 individual articles were identified. Of these 49 met the inclusion criteria for review and 14 were included in a meta-analysis.

Results

Participants included were predominantly female and working age. Median time to infection was 51 days. Reported vaccine effectiveness against infection, symptomatic infection, and infection requiring hospitalisation were between 5 and 100 %, 34 and 100 %, and 65 and 100 % (respectively). No vaccinated HCW deaths were recorded in any study. Pooled estimates of protection against infection, symptomatic infection, and hospitalisation were, respectively, 84.7 % (95 % CI 72.6-91.5 %, p < 0.0001), 86.0 % (95 % CI 67.2 %-94.0 %; p < 0.0001), and 96.1 % (95 % CI 90.4 %-98.4 %). Waning protection against infection was reported by four studies, although protection against hospitalisation for severe infection persists for at least 6 months post vaccination.

Conclusions

Vaccination against SARS-CoV2 in HCWs is protective against infection, symptomatic infection, and hospitalisation. Waning protection is reported but this awaits more mature studies to understand durability more clearly. This study is limited by varying non-pharmacological responses to COVID-19 between included studies, a predominantly female and working age population, and limited information on asymptomatic transmission or long COVID protection.

Vaccination and Its Impact on Lung Involvement in COVID-19 Patients: A Retrospective Study in India

Background COVID-19, caused by SARS-CoV-2, led to a global pandemic necessitating urgent vaccine development and deployment. By the end of 2020, several vaccines had reached their clinical trial endpoints. India, leveraging its pharmaceutical prowess, developed two primary vaccines: CoviShield® and Covaxin®. Despite the availability of these vaccines, vaccine hesitancy became a notable challenge. This study aimed to assess the correlation between vaccination status and lung involvement in COVID-19 patients, aiming to fortify trust in vaccines and enhance vaccine uptake in India. Methods This retrospective cross-sectional study analyzed data from 272 patients treated at a designated COVID-19 Care Center in Chennai, India, from May to July 2021. Patients were divided into vaccinated and unvaccinated groups, with vaccinated individuals further categorized based on the type and dose of vaccine received (CoviShield® or Covaxin®). Lung involvement was assessed through CT chest scans, and statistical analyses were performed to compare the severity of lung involvement across different groups. Results The vaccinated group demonstrated significantly lower mean lung involvement (28%) compared to the unvaccinated group (34.8%). Within vaccinated individuals, no significant differences were observed between different vaccine types and doses, suggesting a generalized protective effect of COVID-19 vaccination against severe lung involvement. Conclusion Vaccination against COVID-19 significantly reduces the severity of lung involvement among patients, irrespective of the vaccine brand or dose. This study reinforces the importance of vaccination in mitigating the impact of COVID-19 and supports ongoing vaccination efforts.

IgG responses against SARS-CoV-2 vaccines AZD1222 and BBV-152 and breakthrough infections among health care workers in southern India

IgG antibodies elicited in response to SARS-CoV-2 are critical in determining the protection achieved through vaccination. The present longitudinal study aims to assess the immune response generated through AZD1222 & BBV-152 vaccination among health care workers (HCWs) in a selected hospital. Serum IgG levels were measured approximately at 1.5 months and 6 months after the first and second vaccination. The final assessment was done 12 months after the first vaccination to analyse the sustained antibody levels. Results showed a progressive increase in antibody titres as a function of time. 26 HCWs in all had SARS-CoV-2 breakthrough infection, but their antibody titres were not significantly higher compared to COVID-19 naïve individuals. However, a comparative analysis showed considerably higher antibody titre in those who received the AZD1222 vaccine among this cohort. AZD1222 vaccination was significantly associated with seropositivity in the first and second assessments. Female HCWs showed significantly higher seropositivity, and participants above 60 years showed considerably reduced antibody titre in the first assessment. However, the final assessment showed no association with these variables, with 97.1 % of participants reporting to be seropositive. The results indicate good antibody response and potential protection against SARS CoV-2.

From rejection to the Nobel Prize: Karikó and Weissman's pioneering work on mRNA vaccines, and the need for diversity and inclusion in translational immunology

Katalin Karikó and Drew Weissman were given the 2023 Nobel Prize in Physiology or Medicine for their findings of nucleoside base modifications that lead to the development of effective mRNA vaccines against COVID-19. This was a remarkable achievement, given that their initial manuscript was rejected by Nature and Science in 2005. The development of mRNA vaccines lagged for more than a decade for several reasons, including the lack of funding, the perceived risks of the technology, and the scepticism of many scientists. Furthermore, Karikó and Weissman's study appeared to be technical and difficult to understand. The COVID-19 pandemic, on the other hand, has shown the importance of mRNA vaccine technology. COVID-19 mRNA vaccines have been highly effective in preventing serious illness, hospitalization, and death. The Nobel Prize for Karikó and Weissman highlights the importance of perseverance, diversity, and inclusion in translational immunology. We need to build a more inclusive scientific community, where scientists from all backgrounds are supported and their work is valued. This will result in more scientific breakthroughs and better healthcare for everyone.

Serological Evaluation of Antibody Titers After Vaccination Against COVID-19 in 18-44-Year-Old Individuals at a Tertiary Care Center

Background The evaluation of the effectiveness of the vaccines (ChAdOx1-nCOV; Covishield and BBV-152; Covaxin) against coronavirus disease 2019 (COVID-19) is necessary to assess their efficacy. Because most antibodies that neutralize the coronavirus are directed against the receptor binding domain within the spike protein of the virus, these antibodies serve as markers for viral neutralizers and, in turn, for vaccine response. The present study aimed to evaluate the anti-neutralizing antibody (receptor binding domain (RBD)) and immunoglobulin G2 (IgG2) titers following the completion of the vaccination schedule (both vaccines) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Methodology In this longitudinal prospective study, conducted in a tertiary care center, 30 sequentially (two doses) vaccinated study participants between the ages of 18 and 44 years were sampled for estimation of anti-RBD antibody titer and IgG2. All statistical analysis was done using SPSS version 20 (IBM Corp., Armonk, NY, USA). P-values less than 0.05 were considered significant. Results There was a statistically significant increase in the neutralizing antibody titer after one month of the second dose (z = -4.597, p < 0.001), while a significant decrease was seen in the IgG2 levels (z = -3.075, p = 0.002). The results showed a significant neutralizing effect of the vaccines being used, with Covishield being more effective than Covaxin. The levels of neutralizing antibodies were independent of all demographic variables such as age, sex, and body mass index. Conclusions This study evaluating the efficacy of the two vaccines, namely, Covishield and Covaxin, is the first of its kind in the state of Chhattisgarh. The results of this study are similar to previous studies conducted in India and outside India, concluding that Covishield is a more effective vaccine.