Importance Cancer patients 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 1 January 2021 to 10 March 2022. Quality was assessed using the Joanna Briggs Institute Critical Appraisal checklist. Results After 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 haematological cancer and 82 solid cancer patients. 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 haematological cancer patients as a reference, lung cancer patients 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. Haematological cancer patients consistently demonstrate poorer response to booster vaccines than solid cancer patients.

  • All age groups
  • Vaccine/vaccination
  • Efficacy/effectiveness
  • COVID-19