Seven-year follow-up of the immune response after one or 2 doses of inactivated hepatitis A vaccine given at 1 year of age in the Mendoza Province of Argentina

Figures & data

Figure 1. Disposition of study participants. *Group 1/Group 2/Group 3.

Table 1. Persistence of anti-HAV antibodies for Years 1 to 5 (MEIA) and Year 7 (ECLIA) after first vaccination.

	Year 1 (95% CI)	Year 2 (95% CI)	Year 3 (95% CI)	Year 4 (95% CI)	Year 5 (95% CI)	Year 7 (95% CI)
Group 1: one dose of Avaxim™ 80U Pediatric prior to inclusion
M	435^a	387	365	343	318	204
≥10 mIU/mL (n [%])	429 (98.6)	387 (100)	364 (99.7)	342 (99.7)	317 (99.7)	—
≥3 mIU/mL (n [%])	—	—	—	—	—	204 (100)
GMC (95% CI)	209.7 (190.6;230.6)	216.0 (198.0;235.7)	170.2 (155.7;186.0)	150.3 (137.4;164.4)	122.5 (111.2;135.0)	125.6 (118.8;141.1)
GMCR (95% CI)	—	0.95 (0.90;1.00)	0.74 (0.70;0.79)	0.66 (0.61;0.70)	0.53 (0.49;0.57)	–
Group 2: two doses of Avaxim™ 80U Pediatric prior to inclusion
M	108	103	94	90	85	53
≥10 mIU/mL (n [%])	107 (99.1)	103 (100)	94 (100)	90 (100)	85 (100)	—
≥3 mIU/mL (n [%])	—	—	—	—	—	53 (100)
GMC (95% CI)	1433.9 (1108.4;1855.1)	1353.8 (1116.2;1641.9)	872.9 (710.2;1073.0)	814.6 (667.4;994.1)	591.7 (479.9;729.4)	712.5 (526.4;964.5)
GMCR (95% CI)	—	0.88 (0.72;1.07)	0.57 (0.47;0.70)	0.54 (0.44;0.66)	0.40 (0.33;0.50)	–
Group 3: one dose of Avaxim™ 80U Pediatric prior to inclusion and one booster dose^b
M	0	6	6	7	8	7
≥10 mIU/mL (n [%])	—	6 (100)	6 (100)	7 (100)	8 (100)	—
≥3 mIU/mL(n [%])	—	—	—	—	—	7 (100)
GMC (95% CI)	—	—	—	—	—	257.2 (81.3;813.6)
Booster performed after visit
M	6	0	1	1	1	0
Pre-booster GMC (95% CI)^c	5 (3.7;6.7)	—	7 (NC)	9 (NC)	9 (NC)	—
Post-booster GMC ([95% CI)^d	551.3 (130.3;2332.2)	—	3000 (NC)	153.0 (NC)	2622.0 (NC)	—
Post-/pre- booster GMCR (95% CI)	110.1 (27.5;440.6)	—	428.57 (NC)	17.0 (NC)	291.33 (NC)	—

^a Immunogenicity data missing for one participant.

^b No participant had a booster at Visit 1. Following Visit 1, 6 participants had low anti-HAV concentrations and received a booster dose – these participants were included in the 1 dose/booster set at Visit 2. Following Visit 3, 1 participant had low anti-HAV concentration and received a booster dose – this participant was included in the 1 dose/booster set at Visit 4. Following Visit 4, 1 participant had low anti-HAV concentration and received a booster dose – this participant was included in the 1 dose/booster set at Visit 5.

^c Sample taken at the indicated visit.

^d Sample taken after the booster regardless of the time window between booster and blood sampling.

n, number of subjects; M, number of participants with available data; CI, confidence interval; GMC, geometric mean concentration (mIU/mL); GMCR, geometric mean concentration ratio against Year 1 (not applicable for Year 7 due to different assays used for Years 1 to 5 [MEIA] and Year 7 [ECLIA]) or post-/pre-booster for Group 3; NC, not calculated (as only 1 participant).