Clinical efficacy and long-term immunogenicity of an early triple dose regimen of SARS-CoV-2 mRNA vaccination in cancer patients

INTRODUCTION@#Three doses of SARS-CoV-2 mRNA vaccines have been recommended for cancer patients to reduce the risk of severe disease. Anti-neoplastic treatment, such as chemotherapy, may affect long-term vaccine immunogenicity.@*METHOD@#Patients with solid or haematological cancer were recruited from 2 hospitals between July 2021 and March 2022. Humoral response was evaluated using GenScript cPASS surrogate virus neutralisation assays. Clinical outcomes were obtained from medical records and national mandatory-reporting databases.@*RESULTS@#A total of 273 patients were recruited, with 40 having haematological malignancies and the rest solid tumours. Among the participants, 204 (74.7%) were receiving active cancer therapy, including 98 (35.9%) undergoing systemic chemotherapy and the rest targeted therapy or immunotherapy. All patients were seronegative at baseline. Seroconversion rates after receiving 1, 2 and 3 doses of SARS-CoV-2 mRNA vaccination were 35.2%, 79.4% and 92.4%, respectively. After 3 doses, patients on active treatment for haematological malignancies had lower antibodies (57.3%±46.2) when compared to patients on immunotherapy (94.1%±9.56, P<0.05) and chemotherapy (92.8%±18.1, P<0.05). SARS-CoV-2 infection was reported in 77 (28.2%) patients, of which 18 were severe. No patient receiving a third dose within 90 days of the second dose experienced severe infection.@*CONCLUSION@#This study demonstrates the benefit of early administration of the third dose among cancer patients.

Associations and prognostic accuracy of electrolyte imbalances in predicting poor COVID-19 outcome: a systematic review and meta-analysis of 28 observational studies

BackgroundSerum electrolyte imbalances are highly prevalent in COVID-19 patients. However, their associations with COVID-19 outcomes are inconsistent, and of unknown prognostic value. ObjectivesTo systematically clarify the associations and prognostic accuracy of electrolyte imbalances (sodium, calcium, potassium, magnesium, chloride and phosphate) in predicting poor COVID-19 clinical outcome. MethodsPubMed, Embase and Cochrane Library were searched. Odds of poor clinical outcome (a composite of mortality, intensive-care unit (ICU) admission, need for respiratory support and acute respiratory distress syndrome) were pooled using mixed-effects models. The associated prognostic sensitivity, positive and negative likelihood ratios (LR+, LR-) and predictive values (PPV, NPV; assuming 25% pre-test probability), and area under the curve (AUC) were computed. ResultsWe included 28 observational studies from 953 records with low to moderate risk-of-bias. Hyponatremia (OR=2.08, 95%CI=1.48-2.94, I2=93%, N=8), hypernatremia (OR=4.32, 95%CI=3.17-5.88, I2=45%, N=7) and hypocalcemia (OR=3.31, 95%CI=2.24-4.88, I2=25%, N=6) were associated with poor COVID-19 outcome. These associations remained significant on adjustment for covariates such as demographics and comorbidities. Hypernatremia was 97% specific in predicting poor outcome (LR+ 4.0, PPV=55%, AUC=0.80) despite no differences in CRP and IL-6 levels between hypernatremic and normonatremic patients. Hypocalcemia was 76% sensitive in predicting poor outcome (LR- 0.44, NPV=87%, AUC=0.71). Overall quality of evidence ranged from very low to moderate. ConclusionHyponatremia, hypernatremia and hypocalcemia are associated with poor COVID-19 clinical outcome. Hypernatremia is 97% specific for a poor outcome and the association is independent of inflammatory marker levels. Further studies should evaluate if correcting these imbalances help improve clinical outcome.

Efficacy of COVID-19 vaccines in immunocompromised patients: A systematic review and meta-analysis

ObjectiveTo compare the efficacy of COVID 19 vaccines between those with immunocompromised medical conditions and those who are immunocompetent DesignSystematic review and meta-analysis Data sourcesPubMed, EMBASE, CENTRAL, CORD-19 and WHO COVID-19 research databases were searched for eligible comparative studies published between 1 December 2020 and 3 September 2021. ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform were searched in September 2021 to identify registered yet unpublished or ongoing studies. Study selectionProspective observational studies which compared the efficacy of COVID-19 vaccination between those with immunocompromising medical conditions and those who were immunocompetent were included. Two reviewers independently screened for potentially eligible studies. Data extractionThe primary outcomes of interest were cumulative incidence of seroconversion after first and second doses of COVID vaccination. Secondary outcomes included SARS-CoV-2 antibody titre level after first and second doses of COVID-19 vaccination. After duplicate data abstraction, a frequentist random effects meta-analysis was conducted. Risk of bias was assessed using the ROBINS-I tool. Certainty of evidence was assessed using the GRADE approach. ResultsAfter screening 3283 studies, 42 studies that met our inclusion criteria were identified. 18 immunocompromised cohorts from 17 studies reported seroconversion in immunocompromised patients compared to healthy controls after the first dose and 30 immunocompromised cohorts in 28 studies reporting data after the second dose. Among immunocompromised groups, in incremental order, transplant recipients had the lowest pooled risk ratio of 0.06 (95%CI: 0.04 to 0.09, I^2=0%, p=0.81) (GRADE=Moderate) followed by haematological cancer patients at 0.36 (95%CI: 0.21 to 0.62, I^2 = 89%, p<0.01) (GRADE=Moderate), solid cancer patients at 0.40 (95%CI: 0.31 to 0.52, I^2 = 63%, p=0.03) (GRADE=Moderate) and IMID patients at 0.66 (95%CI: 0.48 to 0.91, I^2=81%, p<0.01) (GRADE=Moderate). After the second dose, the lowest pooled risk ratio was again seen in transplant recipients at 0.29 (95%CI: 0.21 to 0.40, I^2=91%, p<0.01) (GRADE=Moderate), haematological cancer patients at 0.68 (95%CI: 0.57 to 0.80, I^2=68%, p=0.02) (GRADE=Low), IMID patients at 0.79 (95%CI: 0.72 to 0.86, I^2=87%, p<0.01) (GRADE=Low) and solid cancer at 0.92 (95%CI: 0.89 to 0.95, I^2=26%, p=0.25) (GRADE=Low). ConclusionSeroconversion rates and serological titres are significantly lower in immunocompromised patients with transplant recipients having the poorest outcomes. Additional strategies on top of the conventional 2-dose regimen will likely be warranted, such as a booster dose of the vaccine. Systematic review registrationPROSPERO CRD42021272088