COVID-19 mRNA vaccines can trigger the immune system to recognize and kill cancer, research finds

Remarkably, patients who received either the Pfizer or Moderna mRNA-based COVID-19 vaccine within 100 days of starting immunotherapy were more than twice as likely to be alive after three years compared with those who didn't receive either vaccine.

just exercising some healthy skepticism here, wouldn't people that didn't take the vaccines just be more likely to have died of covid, and also be an indicator of other poor choices? or is there some extra math im missing that accounts for immunodeficient exemption vs choosing no vaccine, etc?

edit: nvm. looking at extended data fig. 2 of the paper, there is definitely not the same overall survival boost with the flu and pneumonia shots compared to the covid mRNA.