Older adults with a history of COVID-19 face higher rates of postoperative delirium after major surgery, impacting surgical outcomes.

• Patients with prior COVID-19 have a 3.09 times greater risk of delirium (p = 0.02).
• Acute postsurgical pain increases the risk of delirium (odds ratio of 1.51; p = 0.02) while vaccination significantly reduces this risk (odds ratio of 0.47; p = 0.01).

Consider promoting COVID-19 vaccinations pre-surgery to mitigate delirium risk in at-risk patients.

• No significant link was found between prior COVID-19 and delayed neurocognitive recovery post-surgery.