Vaccine third dose and cancer patients: necessity or luxury?

The current state of the SARS-CoV-2 pandemic is an equilibrium between expanding vaccine coverage on the one hand, and emergence of variants of concern which compromise vaccine effectiveness and enhance viral transmission on the other. Inequity in vaccine distribution, primarily an ethical issue, challenges this equilibrium, as industrialized countries prepare to administer a third booster dose to their population. Solid tumor cancer patients typically respond well to initial full vaccination and someone could argue that they should not be prioritized for an adjuvant third dose, since protection from severe disease has largely been achieved with the two-dose regimen. Nevertheless, their immune status is dynamic and not all of them exhibit an adequate immune response. A booster third dose is necessary for the inadequate responders, while it will result in better protection of all patients from mild disease as well, which if presented could have ominous consequences due to their overall frailty, and their need to adhere to strict therapeutic schemes. International scientific and public health communities should develop approaches that allow for wide immediate vaccination coverage of the developing world, in parallel with administration of adjuvant doses to solid tumor cancer patients (and other at-risk categories) of the developed nations, in order to avoid prolonging the pandemic, which will be prospectively against cancer patients' best interest. •Significant inequity is observed in vaccine distribution and administration worldwide.•Delta variant dominance and waning vaccine efficacy against infection raise the question of a booster/adjuvant third dose.•General third dose administration in the developed world will limit vaccine access for first doses in the developing nations.•Cancer patients should be prioritized for a third dose, due to immune status defects and necessity to keep their treatments.•Ending this pandemic for all, including our cancer patients, is a global issue and must be addressed as such.