Can a stronger flu shot protect lung transplant patients better?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Lung transplant recipient who enrolled and completed Visits 1, 2, and 3 of the DMID protocol number 22-0014 during the prior 2024-2025 or 2025-2026 influenza season, respectively * Anticipated to be available for the duration of the study * Can be reached by telephone, text message, email, or electronic health record messaging Exclusion Criteria: * Recipient of multi-organ, extra-pulmonary, and/or hematopoietic stem cell transplant * Recipient of a re-do lung transplant * History of Guillain-Barre syndrome * History of receiving the current season's influenza vaccine prior to study enrollment and/or Visit 1 of this follow-up study * Pregnant person * Laboratory-confirmed influenza disease after September 1st in the current influenza season and before enrollment in this follow-up study (patient can still receive the second influenza vaccination despite proven influenza disease after enrollment) * CMVIG/IVIG/SCIG receipt within 28 days of each vaccine * Receipt of rituximab or other B-cell depleting antibody (including proteasome inhibitors) therapy within 3 months of 1st vaccine dose (Day 0) * Receipt of T-cell depleting therapies (anti-thymocyte globulin, alemtuzumab, daratumumab) between the completion of Visit 3 of the initial study and enrollment in this follow-up study * Investigator concern about study participation * Note: Criteria for temporarily delaying vaccine administration: The following conditions are temporary or self-limiting, and a participant may be included in the study once the condition has resolved, provided that the participant is otherwise eligible: * Fever ≥100.4ºF/38.0ºC (oral measurement), or an acute severe illness within 48 hours of enrollment * Receipt of any live vaccines within four weeks or any inactivated vaccines within two weeks prior to potential study vaccination No children have been enrolled in the DMID protocol number 22-0014; therefore, only adults will be enrolled in this current study