. 2021 Jan 20;9(2):69. doi: 10.3390/vaccines9020069

Table 2.

Number of booster vaccinations and/or titre determinations per appointment in 5 different scenarios.

Scenario	Appointment	1	2	3	Total	Mean nr. of Appointments Per Student
A	Booster vaccination	80	0	-	160	2
A	Titre determination	0	80	-	160	2
B	Booster vaccination	0	16	-	112	1.4
B	Titre determination	80	0	16	112	1.4
C	Booster vaccination	49	2	-	133	1.7
C	Titre determination	31	49	2	133	1.7
D	Booster vaccination	23	8	-	119	1.5
D	Titre determination	57	23	8	119	1.5
E	Booster vaccination	8	12	-	112	1.4
E	Titre determination	72	8	12	112	1.4

A. Every student receives a booster vaccination before blood is collected for a titre determination. B. Blood collection for a titre determination is directly performed in all students during first appointment. A booster vaccination is only provided to students with titres < 10 IU/L. C. Students receive a booster at first appointment if their last vaccination is more than 5 years before. Blood collection was performed directly at first appointment in the students who received their last vaccination in the previous 5 years. D. Same as C, but with a cut-off of 10 years for the last vaccination. E. Same as C, but with a cut-off of 15 years for the last vaccination.