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.

Efficacy of covid-19 vaccines in immunocompromised patients: systematic review and meta-analysis.

OBJECTIVE: To compare the efficacy of covid-19 vaccines between immunocompromised and immunocompetent people. DESIGN: Systematic review and meta-analysis. DATA SOURCES: PubMed, Embase, Central Register of Controlled Trials, COVID-19 Open Research Dataset Challenge (CORD-19), and WHO covid-19 databases for studies published between 1 December 2020 and 5 November 2021. ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform were searched in November 2021 to identify registered but as yet unpublished or ongoing studies. STUDY SELECTION: Prospective observational studies comparing the efficacy of covid-19 vaccination in immunocompromised and immunocompetent participants. METHODS: A frequentist random effects meta-analysis was used to separately pool relative and absolute risks of seroconversion after the first and second doses of a covid-19 vaccine. Systematic review without meta-analysis of SARS-CoV-2 antibody titre levels was performed after first, second, and third vaccine doses and the seroconversion rate after a third dose. Risk of bias and certainty of evidence were assessed. RESULTS: 82 studies were included in the meta-analysis. Of these studies, 77 (94%) used mRNA vaccines, 16 (20%) viral vector vaccines, and 4 (5%) inactivated whole virus vaccines. 63 studies were assessed to be at low risk of bias and 19 at moderate risk of bias. After one vaccine dose, seroconversion was about half as likely in patients with haematological cancers (risk ratio 0.40, 95% confidence interval 0.32 to 0.50, I2=80%; absolute risk 0.29, 95% confidence interval 0.20 to 0.40, I2=89%), immune mediated inflammatory disorders (0.53, 0.39 to 0.71, I2=89%; 0.29, 0.11 to 0.58, I2=97%), and solid cancers (0.55, 0.46 to 0.65, I2=78%; 0.44, 0.36 to 0.53, I2=84%) compared with immunocompetent controls, whereas organ transplant recipients were 16 times less likely to seroconvert (0.06, 0.04 to 0.09, I2=0%; 0.06, 0.04 to 0.08, I2=0%). After a second dose, seroconversion remained least likely in transplant recipients (0.39, 0.32 to 0.46, I2=92%; 0.35, 0.26 to 0.46), with only a third achieving seroconversion. Seroconversion was increasingly likely in patients with haematological cancers (0.63, 0.57 to 0.69, I2=88%; 0.62, 0.54 to 0.70, I2=90%), immune mediated inflammatory disorders (0.75, 0.69 to 0.82, I2=92%; 0.77, 0.66 to 0.85, I2=93%), and solid cancers (0.90, 0.88 to 0.93, I2=51%; 0.89, 0.86 to 0.91, I2=49%). Seroconversion was similar between people with HIV and immunocompetent controls (1.00, 0.98 to 1.01, I2=0%; 0.97, 0.83 to 1.00, I2=89%). Systematic review of 11 studies showed that a third dose of a covid-19 mRNA vaccine was associated with seroconversion among vaccine non-responders with solid cancers, haematological cancers, and immune mediated inflammatory disorders, although response was variable in transplant recipients and inadequately studied in people with HIV and those receiving non-mRNA vaccines. CONCLUSION: Seroconversion rates after covid-19 vaccination were significantly lower in immunocompromised patients, especially organ transplant recipients. A second dose was associated with consistently improved seroconversion across all patient groups, albeit at a lower magnitude for organ transplant recipients. Targeted interventions for immunocompromised patients, including a third (booster) dose, should be performed. SYSTEMATIC REVIEW REGISTRATION: PROSPERO CRD42021272088.

Booster doses of COVID-19 vaccines for patients with haematological and solid cancer: a systematic review and individual patient data meta-analysis.

IMPORTANCE: Patients with cancer have an increased risk of severe disease and mortality from COVID-19, as the disease and antineoplastic therapy cause reduced vaccine immunogenicity. Booster doses have been proposed to enhance protection, and efficacy data are emerging from several studies. OBJECTIVE: To evaluate the proportion of COVID-19 primary vaccination non-responders with cancer who seroconvert after a booster dose. METHODS: PubMed, EMBASE, CENTRAL and medRxiv were searched from 1st January 2021 to 10th March 2022. Quality was assessed using the Joanna Briggs Institute Critical Appraisal checklist. RESULTS: After the eligibility assessment, 22 studies were included in this systematic review and 17 for meta-analysis of seroconversion in non-responders, pooling a total of 849 patients with haematological cancer and 82 patients with solid cancer. Haematological cancer non-responders exhibited lower seroconversion at 44% (95% CI 36-53%) than solid cancer at 80% (95% CI 69-87%). Individual patient data meta-analysis found the odds of having a meaningful rise in antibody titres to be significantly associated with increased duration between the second and third dose (OR 1.02, 95% CI 1.00-1.03, P ≤ 0.05), age of patient (OR 0.960, 95% CI 0.934-0.987, P ≤ 0.05) and cancer type. With patients with haematological cancer as a reference, patients with lung cancer had 16.8 times the odds of achieving a meaningful increase in antibody titres (OR 16.8, 95% CI 2.95-318, P ≤ 0.05) and gastrointestinal cancer patients had 25.4 times the odds of achieving a meaningful increase in antibody titres (OR 25.4, 95% CI 5.26-492.21, P ≤ 0.05). CONCLUSIONS: administration of a COVID-19 vaccine booster dose is effective in improving seroconversion and antibody levels. Patients with haematological cancer consistently demonstrate poorer response to booster vaccines than patients with solid cancer.

Booster COVID-19 Vaccines for Immune-Mediated Inflammatory Disease Patients: A Systematic Review and Meta-Analysis of Efficacy and Safety.

BACKGROUND: Seroconversion and longevity of vaccine-induced immune response is blunted in immune-mediated inflammatory disease (IMID) patients owing to immunosuppressive regimens. COVID-19 booster vaccines after a primary series have been proposed with inconclusive evidence on efficacy to date. METHODS: This PROSPERO-registered systematic review (CRD42022302534) was conducted according to PRISMA guidelines. PubMed, EMBASE, CENTRAL, Web of Science, CORD-19, WHO ICTRP, and medRxiv were searched up to 28 February 2022 for eligible studies. Risk of bias was assessed using the Joanna Briggs Institute critical appraisal tools. RESULTS: From 6647 records, 17 prospective studies were included for systematic review and 12 in meta-analysis of primary series non-responders. The risk of bias was low. Pooling 340 non-responders, a booster dose proved effective with 0.47 seroconverting (95% CI: 0.32-0.63, I2 = 82%). Rituximab therapy was associated with significant impairment, with risks of 0.25 (95% CI: 0.17-0.36, I2 = 50.7%) versus 0.81 (95% CI: 0.72-0.87, I2 = 0.0%) for those without rituximab therapy. A systematic review of antibody levels against COVID-19 showed several-fold increases across studies. Incidence of local and systemic adverse events, including disease flares, were either comparable or slightly increased after the booster dose compared to primary series. No major events such as myocarditis or death were reported. CONCLUSION: Our results show that booster doses are effective in eliciting seroconversion in non-responders, bolstering immunity to COVID-19. It has also not been associated with major adverse events.