Clinical effectiveness of SARS-CoV-2 vaccines and booster doses in patients with cancer: An analysis from the European OnCovid registry.

Abstract

e18725 Background: Immunogenicity and safety of SARS-CoV-2 vaccines have been widely investigated in patients (pts) with cancer. However, their effectiveness against Coronavirus disease 2019 (COVID-19) and the additional protective effect of a booster dose in this population are yet to be defined. Methods: Using OnCovid study data (NCT04393974), a European registry enrolling consecutive pts with cancer and COVID-19, we evaluated morbidity and 14 days case fatality rates (CFR14) from COVID-19 in pts who were unvaccinated, vaccinated (either partially/full vaccinated but not boosted) and those who had received a third dose. Analyses were restricted to pts diagnosed between 17/11/2021 (first breakthrough infection in a boosted pt) and the 31/01/2022. Pts with unknown vaccination status were excluded. Results: By the data lock of 22/02/2022, out of 3820 consecutive pts from 36 institutions, 415 pts from 3 countries (UK, Spain, Italy) were eligible for analysis. Among them, 51 (12.3%) were unvaccinated, 178 (42.9%) were vaccinated and 186 (44.8%) were boosted. Among vaccinated pts, 26 (14.6%) were partially vaccinated (1 dose). Pts with haematological malignancies had more likely received a booster dose prior to infection (25.4% vs 13.6% and 11.8%, p = 0.02). We found no other associations between vaccination status and pts’ characteristics including sex, age, comorbidities, smoking history, tumour stage, tumour status and receipt of systemic anticancer therapy. Compared to unvaccinated pts, boosted and vaccinated pts achieved improved CFR14 (6.8% and 7.0% vs 22.4%, p = 0.01), COVID-19-related hospitalization rates (26.1% and 20.6% vs 41.2%, p = 0.01) and COVID-19-related complications rates (14.5% and 15.7% vs 31.4%). Using multivariable Inverse Probability of Treatment Weighting (IPTW) models adjusted for sex, comorbidities, tumour status and country of origin we confirmed that boosted (OR 0.21, 95%CI: 0.05-0.89) and vaccinated pts (OR 0.19, 95%CI: 0.04-0.81) achieved improved CFR14 compared to unvaccinated pts, whilst a significantly reduced risk of COVID-19 complications (OR 0.26, 95%CI: 0.07-0.93) was reported for vaccinated pts only. Conclusions: SARS-CoV-2 vaccines protect from COVID-19 morbidity and mortality in pts with cancer. Accounting for the enrichment of haematologic pts in the boosted group, the observation of comparable mortality outcomes between boosted and vaccinated pts is reassuring and suggests boosting to be associated with reduced mortality in more vulnerable subjects, despite evidence of adverse features in this group.

SARS-CoV-2 omicron (B.1.1.529)-related COVID-19 sequelae in vaccinated and unvaccinated patients with cancer: results from the OnCovid registry

“…The following covariates were used: country (the UK vs Spain vs Italy), sex (male vs female), number of comorbidities (0-1 vs ≥2), primary tumour, tumour stage at COVID-19 diagnosis (advanced vs non-advanced), tumour status at COVID-19 diagnosis (active vs non-active), receipt of systemic anticancer therapy within 4 weeks before COVID-19 diagnosis (yes vs no), and age with the 65 years cutoff that has been concordantly used in our registry (≥65 vs <65 years). [7][8][9][10]13,14 To obtain more balanced models, we included variables with missing data by grouping them as reference term in case of a less than 5% of missingness and as an "unknown" category in case of a 5% or more of missingness. Last, in view of the fact that sequelae evaluation and assessments were not predefined across centres, and that the data source consisted of 20 different institutions, all 95% CIs for COVID-19 sequelae comparisons were corrected following a clustered-robust adjustment for participating centre.…”

“…Limited, but plausible, evidence suggests that previous SARS-CoV-2 vaccination might reduce the prevalence of COVID-19 sequelae in patients with cancer. 10 However, novel SARS-CoV-2 variants are capable of evading vaccinal immunity, and new vaccines have now been developed to overcome immune evasion. 11,12 Although recent evidence suggests that overall SARS-CoV-2 infections diagnosed during the outbreak of the omicron (B.1.1.529) variant are associated with improved COVID-19 outcomes in comparison to previous phases of the pandemic, 13 we showed that improvement in mortality was mainly driven by previous vaccinal immunity, arguing against the hypothesis of an inherently reduced pathogenicity of the omicron variant in patients with cancer.…”

Definition and measurement of post-COVID-19 conditions in real-world practice: a global systematic literature review

“…Due to substantial heterogeneity in terminology used to assess symptoms/conditions, both via clinical diagnoses and patient-reported methods, outcomes in this SLR were extracted verbatim before grouping by organ and system class to facilitate analyses. Existing approaches in the literature and medical specialists were consulted 19–22. Individual symptoms and conditions were grouped by domains, as described in online supplemental table 5.…”

The effectiveness of COVID-19 vaccine in the prevention of post-COVID conditions: a systematic literature review and meta-analysis of the latest research

“…Thirty-two studies met the inclusion criteria [14][15][16][17] and were included in the final review (Table 1). All studies were nonrandomized [14][15][16][17] ; of these, fourteen were retrospective cohort studies, 15,25,[29][30][31]35,36,40,[44][45][46]48,49,51 nine were prospective cohort studies 14,16,28,32,34,37,38,41,50 , five were cross-sectional studies, 17,24,42,43,47 and four were case-control studies. 26,27,33,39 One of the cross-sectional studies was also within a prospective cohort study.…”