Lung transplant recipients (LTR) are susceptible to severe COVID-19 and had lower immune responses to primary SARS-CoV-2 vaccination as compared to the general population and to other solid organ transplant recipients. As immunity induced by booster vaccination and natural infection has increased since the beginning of the pandemic in the general population, immunity acquired by LTR is not well documented. Humoral and cellular immunity to SARS-CoV-2 was monitored in February and May 2023 in 30 LTR and compared to that of health care workers (HCW) and nursing home residents (NHR). LTR had significantly lower levels of SARS-CoV-2 binding and neutralizing antibodies and lower IFN-γ responses to Wuhan, Delta and XBB1.5 variants as compared to HCW and NHR. Humoral immunity decreased between the two visits whereas cellular immunity remained more stable. The persistent defect in SARS-CoV-2 immunity in LTR should encourage continued monitoring and preventive measures for this vulnerable population.