Volume 30, Number 6—June 2024
Research
Follow-Up Study of Effectiveness of 23-Valent Pneumococcal Polysaccharide Vaccine Against All-Type and Serotype-Specific Invasive Pneumococcal Disease, Denmark
Katrine Finderup Nielsen1
, Lise Birk Nielsen1, Tine Dalby, Frederikke Kristensen Lomholt, Hans-Christian Slotved, Kurt Fuursted, Zitta Barrella Harboe, Charlotte Sværke Jørgensen, and Palle Valentiner-Branth
, Lise Birk Nielsen1, Tine Dalby, Frederikke Kristensen Lomholt, Hans-Christian Slotved, Kurt Fuursted, Zitta Barrella Harboe, Charlotte Sværke Jørgensen, and Palle Valentiner-Branth
Table 3
Hazard ratios and effectiveness of PPSV23 vaccine against IPD in follow-up study, comparing time since vaccination with PPSV23 with no vaccination, Denmark, April 22, 2020–March 15, 2023*
| IPD type | Vaccination status | No. events | Person-years | VE, % (95% CI) |
|
|---|---|---|---|---|---|
| Unadjusted | Adjusted† | ||||
| All | Unvaccinated | 200 | 1,277,147 | Referent | |
| 0–1 y after vaccination | 74 | 838,041 | 38 (18–53) | 39 (19–53) | |
| 1–2 y after vaccination | 131 | 728,480 | 24 (3–40) | 30 (10–45) | |
| 2–3 y after vaccination |
108 |
353,319 |
14 (−15 to 36) |
27 (2–46) |
|
| PPSV23 serotype | Unvaccinated | 134 | 1,277,147 | Referent | |
| 0–1 y after vaccination | 38 | 838,041 | 51 (29–66) | 52 (30–67) | |
| 1–2 y after vaccination | 85 | 728,480 | 25 (−2 to 44) | 30 (5–48) | |
| 2–3 y after vaccination |
63 |
353,319 |
34 (5–54) |
43 (19–61) |
|
| PPSV23 serotype excluding serotype 3 | Unvaccinated | 105 | 1,277,147 | Referent | |
| 0–1 y after vaccination | 23 | 838,041 | 64 (43–78) | 65 (44–78) | |
| 1–2 y after vaccination | 44 | 728,480 | 47 (22–64) | 52 (29–67) | |
| 2–3 y after vaccination |
35 |
353,319 |
49 (20–68) |
57 (32–73) |
|
| Serotype 3 | Unvaccinated | 29 | 1,277,147 | Referent | |
| 0–1 y after vaccination | 15 | 838,041 | −2 (−95 to 46) | −2 (−94 to 47) | |
| 1–2 y after vaccination | 41 | 728,480 | −47 (−148 to 13) | −39 (−135 to 18) | |
| 2–3 y after vaccination |
28 |
353,319 |
−14 (−110 to 38) |
−1 (−87 to 46) |
|
| Serotype 8 | Unvaccinated | 32 | 1,277,147 | Referent | |
| 0–1 y after vaccination | 3 | 838,041 | 86 (52–96) | 86 (54–96) | |
| 1–2 y after vaccination | 15 | 728,480 | 37 (−24 to 68) | 46 (−8 to 73) | |
| 2–3 y after vaccination |
9 |
353,319 |
34 (−71 to 74) |
48 (−35 to 80) |
|
| Serotype 22F | Unvaccinated | 25 | 1,277,147 | Referent | |
| 0–1 y after vaccination | 1 | 838,041 | 92 (40–99) | 92 (39–99) | |
| 1–2 y after vaccination | 3 | 728,480 | 88 (59–96) | 89 (64–97) | |
| 2–3 y after vaccination | 5 | 353,319 | 82 (47–94) | 86 (60–95) | |
*IPD, invasive pneumococcal disease; PCV15, 15-valent pneumococcal conjugate vaccine; PCV20, 20-valent pneumococcal conjugate vaccine; PPSV23, 23-valent polysaccharide pneumococcal vaccine; VE, vaccine effectiveness. †Adjusted for age and comorbidities as a restricted cubic spline and sex as a categorical variable.
1These authors contributed equally to this article.
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