Table 3.

Neutralizing antibody titers of 5 subjects seropositive at baseline.

	Neutralizing Antibody Titer
	Day 0	28 days after primary vac.	1 year	28 days after booster vac.	Type of immune response
Subject 1	11	127	39	158	Primary
Subject 2	11	2,101	160	1,208	Secondary
Subject 3	861	63,760	15,383	24,100	Secondary
Subject 4	206	52,778	19,85	5,545	Secondary
Subject 5	1,168	30,431	2,034	1,732	Secondary