Table 3.
Immune Responses to 1 and 2 Doses of the 2009 H1N1 Vaccine at 15 μg or 30 μg Hemagglutinin per Dose, Using the Hemagglutination Inhibition and Microneutralization Assays
| CD4 <200 cells/mL |
CD4 ≥200 cells/mL |
|||
| 15 μg HA | 30 μg HA | 15 μg HA | 30 μg HA | |
| Response | (n = 35) | (n = 36) | (n = 60) | (n = 61) |
| Prevaccination | ||||
| Percentage with HAI titer ≥40 (95% CI) | 21 (9–38) | 24 (11–41) | 18 (10–30) | 18 (9–30) |
| 10 days post–dose 1 (day 10) | ||||
| Percentage with HAI titer ≥40 (95% CI) | 47 (30–65) | 71 (53–85) | 67 (53–78) | 78 (65–87) |
| Percentage with seroconversion (95% CI) | 41a (25–59) | 68a (49–83) | 53 (40–66) | 72 (59–83) |
| 21 days post–dose 1 (day 21) | ||||
| Percentage with HAI titer ≥40 (95% CI) | 47 (30–65) | 69 (50–84) | 64 (50–76) | 75 (62–85) |
| Percentage with seroconversion (95% CI) | 41a (25–59) | 66a (47–81) | 52b (38–65) | 70b (57–81) |
| 10 days post–dose 2 (day 31) | ||||
| Percentage with HAI titer ≥40 (95% CI) | 50 (32–68) | 73 (54–87) | 69 (55–81) | 75 (62–86) |
| Percentage with HAI seroconversion (95% CI) | 44 (27–62) | 70 (51–84) | 58 (44–71) | 72 (58–83) |
| 21 days post–dose 2 (day 42) | ||||
| Percentage with HAI titer ≥40 (95% CI) | 59 (41–75) | 69 (50–84) | 65 (51–78) | 74 (60–84) |
| Percentage with seroconversion (95% CI) | 53 (35–70) | 59 (41–76) | 55 (41–68) | 70 (57–82) |
| 180 days post–dose 2 (day 201) | ||||
| Percentage with HAI titer ≥40 (95% CI) | 36 (20–55) | 59 (41–76) | 46 (33–60) | 58 (44–71) |
| Percentage with serconversion (95% CI) | 27 (13–46) | 41 (24–59) | 30a (18–44) | 49a (35–63) |
| Prevaccination | ||||
| Percentage with MN titer ≥40 (95% CI) | 29 (15–47) | 38 (22–56) | 28 (17–41) | 34 (23–48) |
| 10 days post–dose 1 (day 10) | ||||
| Percentage with MN titer ≥40 (95% CI) | 68 (49–83) | 85 (69–95) | 78 (66–88) | 91 (81–97) |
| Percentage with seroconversion (95% CI) | 59b (41–75) | 82b (65–93) | 63 (50–75) | 88 (76–95) |
| 21 days post–dose 1 (day 21) | ||||
| Percentage with MN titer ≥40 (95% CI) | 68 (49–83) | 81 (64–93) | 79 (66–89) | 85 (73–93) |
| Percentage with seroconversion (95% CI) | 59 (41–75) | 75 (57–89) | 65 (51–77) | 80 (67–89) |
| 10 days post–dose 2 (day 31) | ||||
| Percentage with MN titer ≥40 (95% CI) | 74 (56–87) | 88 (71–96) | 93 (82–98) | 84 (72–93) |
| Percentage with seroconversion (95% CI) | 65 (46–80) | 81 (64–93) | 73 (59–84) | 81 (68–90) |
| 21 days post–dose 2 (day 42) | ||||
| Percentage with MN titer ≥40 (95% CI) | 76 (59–89) | 78 (60–91) | 91 (80–97) | 86 (74–94) |
| Percentage with seroconversion (95% CI) | 68 (49–83) | 75 (57–89) | 75 (61–85) | 82 (70–91) |
| 180 days post–dose 2 (day 201) | ||||
| Percentage with MN titer ≥40 (95% CI) | 52 (34–69) | 63 (44–79) | 52 (38–66) | 69 (55–81) |
| Percentage with seroconversion (95% CI) | 36 (20–55) | 31 (16–50) | 31 (20–46) | 47 (34–61) |
Bold faced values represent P < .05 for the comparison between the 15-μg and 30-μg HA groups.
Abbreviations: CI, confidence interval; HA, hemagglutinin; HAI, hemagglutination inhibition assay; MN, microneutralization assay.
a
P = .05 for comparison of the variables between the 15-μg and 30-μg HA groups.
b
P = .06 for comparison of the variables between the 15-μg and 30-μg HA groups.