Protection after yellow fever vaccination in patients using medication suppressing the immune system.

Rationale:

The immune response following yellow fever vaccinations may be suboptimal in those using immunosuppressive medication. Possibly, this population has a less durable and lower immunologic memory response compared to healthy controls, and more frequent revaccination might be required in this group.



Objective:

Our main objective is to compare duration and height of immune memory in vaccinees who were using immunosuppressive medication at the time of vaccination to health vaccinees. Our secondary outcome measures are antibodies present and adverse events in both groups.



Study design:

Retrospective observational study.



Study population:

Patients using immunosuppressive medication vaccinated with the yellow fever vaccine maximum 20 years ago, aged > 18 years shall be included. Healthy controls matched by age, sex and time after vaccination shall be included as well.



Main study parameters/endpoints:

The main endpoint is the proportion of those with immunologic memory in the patient group compared to the control group.



Nature and extent of the burden and risks associated with participation, benefit and group relatedness:

Participants shall be asked to fill in one questionnaire on adverse events and a venapunction shall be performed at one clinical visit. Risks are bruising and pain of the arm (both expected to be mild and transient). Benefits for participants are increased insight in their immunologic response and the awareness of protection against the yellow fever virus.

Yellow fever specific T cells are present in 70% of patients using immunosuppressive medication versus 99% of healthy volunteers.

N/A

1. Administration of a questionnaire about adverse events following vaccination;

2. Venapunction (54 mL) on 1 day.