Fig. 4.

Kaplan-Meier plots of cumulative COVID-19 infection over time. Fig. 4A demonstrates comparable impact of vaccination and of boosting in Veterans without/with a diagnosis of cancer. Comparable results with a single dose of the mRNA vaccines are observed in the group of Veterans who received only one dose of either mRNA vaccine [Full dose v One dose: HR, 0.827, 95%CI, 0.728–0.939, P = 0.0033]. Hazard ratios for combined Noncancer + Cancer (95%CI): One dose vs. Unvaccinated: 0.260 (0.229–0.295). Full dose vs. Unvaccinated: 0.220 (0.213–0.228). Full dose + booster v Unvaccinated: 0.141 (0.141–0.150). The analysis excludes 733 Veterans who died and 262 who were infected before the 2nd dose could be administered. See Supplementary Fig. 2 for discussion and alternate plots. Fig. 4B documents an increasing rate of infection that begins sooner with the Janssen vaccine and at 6–8 months after completing both vaccinations with the Pfizer-BioNTech and Moderna mRNA products. For the 3 vaccinations, the administration of a booster delays the rise of the infections but does not meaningfully change the qualitative shape of the rising curve consistent with transient increases in the level of immunity but not a change in immune competence and its durability.