Real-world effectiveness of COVID-19 vaccines: a literature review and meta-analysis

AGA Rapid Review and Guideline for SARS-CoV2 Testing and Endoscopy Post-Vaccination: 2021 Update.

Background and aims Symptomatic or asymptomatic COVID-19 infection has been reported in vaccination. In the current article, we try to elucidate various causes behind COVID-19 infection and mortality following COVID-19 vaccination and suggest possible strategies to counteract this threat. Methods We carried out a comprehensive review of the literature using suitable keywords such as ‘COVID-19’, ‘Pandemics’, ‘Vaccines’, ‘Mortality’, ‘deaths’, ‘infections’, and ‘India’ on the search engines of PubMed, SCOPUS, Google Scholar, and ResearchGate in from January to May 2021. Epidemiology, risk factors, Adverse Events Following Immunization (AEFI) and mortality after COVID-19 vaccination were assessed. Results A number of factors have been associated with symptomatic or asymptomatic COVID-19 infection reported after vaccination. A high viral load, comorbidities, mutant strains, Variants of Concern (VOC) leading to Vaccine escape and casual attitude towards COVID Appropriate Behaviors appear to be the most important factors for infection and deaths after COVID-19 vaccination. Conclusions COVID-19 Infection and mortality after COVID-19 vaccination are of great concern. Application of COVID Appropriate Behaviour (CAB) before and after vaccination is essential for the population. Effective Vaccines against mutant strains and enhanced vaccination drive are key strategies to avoid this quintessential threat. Early medical intervention in high-risk groups can prevent overall mortality.

Elucidating causes of COVID-19 infection and related deaths after vaccination.

Background: Self-reported symptom studies rapidly increased our understanding of SARS-CoV-2 during the pandemic and enabled the monitoring of long-term effects of COVID-19 outside the hospital setting. It is now evident that post-COVID syndrome presents with heterogeneous profiles, which need characterisation to enable personalised care among the most affected survivors. This study describes post-COVID profiles, and how they relate to different viral variants and vaccination status. Methods: In this prospective longitudinal cohort study, we analysed data from 336,652 subjects, with regular health reports through the Covid Symptom Study (CSS) smartphone application. These subjects had reported feeling physically normal for at least 30 days before testing positive for SARS-CoV-2. 9,323 individuals subsequently developed Long-COVID, defined as symptoms lasting longer than 28 days. 1,459 had post-COVID syndrome, defined as more than 12 weeks of symptoms. Clustering analysis of the time-series data was performed to identify distinct symptom profiles for post-COVID patients, across variants of SARS-CoV-2 and vaccination status at the time of infection. Clusters were then characterised based on symptom prevalence, duration, demography, and prior conditions (comorbidities). Using an independent testing sample with additional data (n=140), we investigated the impact of post-COVID symptom clusters on the lives of affected individuals. Findings: We identified distinct profiles of symptoms for post-COVID syndrome within and across variants: four endotypes were identified for infections due to the wild-type variant; seven for the alpha variant; and five for delta. Across all variants, a cardiorespiratory cluster of symptoms was identified. A second cluster related to central neurological, and a third to cases with the most severe and debilitating multi-organ symptoms. Gastrointestinal symptoms clustered in no more than two specific phenotypes per viral variant. The three main clusters were confirmed in an independent testing sample, and their functional impact was assessed. Interpretation: Unsupervised analysis identified different post-COVID profiles, characterised by differing symptom combinations, durations, and functional outcomes. Phenotypes were at least partially concordant with individuals reported experiences. Our classification may be useful to understand distinct mechanisms of the post-COVID syndrome, as well as subgroups of individuals at risk of prolonged debilitation. Funding: UK Government Department of Health and Social Care, Chronic Disease Research Foundation, The Wellcome Trust, UK Engineering and Physical Sciences Research Council, UK Research and Innovation London Medical Imaging & Artificial Intelligence Centre for Value-Based Healthcare, UK National Institute for Health Research, UK Medical Research Council, British Heart Foundation and Alzheimers Society, and ZOE Limited, UK.

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Profiling post-COVID syndrome across different variants of SARS-CoV-2

Real-world effectiveness studies are important for monitoring performance of COVID-19 vaccination programmes and informing COVID-19 prevention and control policies. We aimed to synthesise methodological approaches used in COVID-19 vaccine effectiveness studies, in order to evaluate which approaches are most appropriate to implement in low- and middle-income countries (LMICs). For this rapid systematic review, we searched PubMed and Scopus for articles published from inception to July 7, 2021, without language restrictions. We included any type of peer-reviewed observational study measuring COVID-19 vaccine effectiveness, for any population. We excluded randomised control trials and modelling studies. All data used in the analysis were extracted from included papers. We used a standardised data extraction form, modified from STrengthening the Reporting of OBservational studies in Epidemiology (STROBE). Study quality was assessed using the REal Life EVidence AssessmeNt Tool (RELEVANT) tool. This study is registered with PROSPERO, CRD42021264658. Our search identified 3,327 studies, of which 42 were eligible for analysis. Most studies (97.5%) were conducted in high-income countries and the majority assessed mRNA vaccines (78% mRNA only, 17% mRNA and viral vector, 2.5% viral vector, 2.5% inactivated vaccine). Thirty-five of the studies (83%) used a cohort study design. Across studies, short follow-up time and limited assessment and mitigation of potential confounders, including previous SARS-CoV-2 infection and healthcare seeking behaviour, were major limitations. This review summarises methodological approaches for evaluating real-world effectiveness of COVID-19 vaccines and highlights the lack of such studies in LMICs, as well as the importance of context-specific vaccine effectiveness data. Further research in LMICs will refine guidance for conducting real-world COVID-19 vaccine effectiveness studies in resource-constrained settings. 

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A systematic review of methodological approaches for evaluating real-world effectiveness of COVID-19 vaccines: Advising resource-constrained settings

The initial impact of a national BNT162b2 mRNA COVID-19 vaccine rollout.

ObjectiveWe herein report the initial impact of a national BNT162b2 rollout on SARS-CoV-2 infections in Qatar. MethodsWe included all individuals who by 16 March 2021 had completed [≥]14 days of follow up after the receipt of BNT162b2. We calculated incidence rates (IR) and their 95% confidence intervals (CI), during days 1-7, 8-14, 15-21, 22-28, and >28 days post-vaccination. Poisson regression was used to calculate incidence rate ratios (IRR) relative to the first 7-day post-vaccination period. ResultsWe included 199,219 individuals with 6,521,124 person-days of follow up. SARS-CoV-2 infection was confirmed in 1,877 (0.9%), of which 489 (26.1%) were asymptomatic and 123 (6.6%) required oxygen support. The median time from first vaccination to SARS-CoV-2 confirmation was 11.9 days (IQR 7.7-18.2). Compared with the first 7-day post-vaccination period, SARS-CoV-2 infections were lower by 65.8-84.7% during days 15-21, days 22-28, and >28 days (P <0.001 for each). For severe COVID-19, the incidence rates were 75.7- 93.3% lower (P <0.001 for each) during the corresponding time periods. ConclusionOur results are consistent with an early protective effect of BNT162b2 against all degrees of SARS-CoV-2 severity.

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Saleh A.N. Hussein

Papers

The initial impact of a national BNT162b2 mRNA COVID-19 vaccine rollout.

The initial impact of a national BNT162b2 mRNA COVID-19 vaccine rollout