Volume 24, Number 7—July 2018
Research
Registry Cohort Study to Determine Risk for Multiple Sclerosis after Vaccination for Pandemic Influenza A(H1N1) with Arepanrix, Manitoba, Canada
Salaheddin M. Mahmud
, Songul Bozat-Emre, Luiz C. Mostaço-Guidolin, and Ruth Ann Marrie
, Songul Bozat-Emre, Luiz C. Mostaço-Guidolin, and Ruth Ann Marrie
Table 2
Crude and age-standardized rates of incident multiple sclerosis and influenza vaccination status, Manitoba, Canada, 2009–2012*
| Vaccination status |
No. events |
Rate (95% CI) | Rate ratio (95% CI) | |||
|---|---|---|---|---|---|---|
| Crude |
Age-standardized |
Crude |
Age-adjusted |
|||
| 1 year after index date | ||||||
| Unvaccinated | 106 | 23.2 (19.2–28.0) | 24.2 (20.1–28.3) | 1 | 1 | |
| Vaccinated A(H1N1) pdm09/TIV | 69 | 19.1 (15.1–24.2) | 20.2 (15.4–24.9) | 0.8 (0.6–1.1) | 0.8 (0.3–2.2) | |
| A(H1N1)pdm09 alone | 43 | 17.6 (13.1–23.8) | 17.7 (14.1–21.2) | 0.8 (0.5–1.1) | 0.7 (0.3–1.7) | |
| Concurrent A(H1N1)pdm09/TIV | 12 | 20.3 (11.5–35.7) | 19.4 (8.6–30.2) | 0.9 (0.5–1.6) | 0.8 (0.1–5.0) | |
| TIV alone | 14 | 24.3 (14.4–41.1) | 36.8 (25.0–48.6) | 1.0 (0.6–1.8) | 1.5 (0.3–6.8) | |
| Adjuvanted A(H1N1)pdm09 alone | 40 | 17.1 (12.5–23.3) | 17.4 (13.8–21.1) | 0.7 (0.5–1.1) | 0.7 (0.3–1.7) | |
| Concurrent adjuvanted A(H1N1)pdm09/TIV | 11 | 19.2 (10.6–34.7) | 18.3 (7.3–29.3) | 0.8 (0.4–1.5) | 0.8 (0.1–5.1) | |
| Unadjuvanted A(H1N1)pdm09 alone | s | s | 18.6 (8.8–28.3) | 1.3 (0.4–4.2) | 0.8 (0.1–4.2) | |
| Concurrent unadjuvanted A(H1N1)pdm09/TIV |
s |
s |
37.9 (13.8–62.0) |
2.3 (0.3–16.4) |
1.6 (0.1–26.6) |
|
| Entire follow-up period | ||||||
| Unvaccinated | 188 | 15.6 (13.5–18.0) | 16.0 (13.5–18.5) | 1 | 1 | |
| Vaccinated A(H1N1)pdm09/TIV | 132 | 15.1 (12.7–17.9) | 15.4 (12.4–18.4) | 1.0 (0.8–1.2) | 1.0 (0.5–1.9) | |
| A(H1N1)pdm09 alone | 82 | 14.6 (11.7–18.1) | 14.9 (9.3–20.5) | 0.9 (0.7–1.2) | 0.9 (0.3–2.8) | |
| Concurrent A(H1N1)pdm09/TIV | 33 | 20.1 (14.3–28.2) | 18.2 (11.8–24.6) | 1.3 (0.9–1.9) | 1.1 (0.4–3.6) | |
| TIV alone | 17 | 11.4 (7.1–18.4) | 16.6 (9.5–23.8) | 0.7 (0.4–1.2) | 1.0 (0.3–3.9) | |
| Adjuvanted A(H1N1)pdm09 alone | 78 | 14.5 (11.6–18.0) | 15.0 (9.3–20.7) | 0.9 (0.7–1.2) | 0.9 (0.3–2.9) | |
| Concurrent adjuvanted A(H1N1)pdm09/TIV | 32 | 20.1 (14.2–28.4) | 18.4 (11.9–24.9) | 1.3 (0.9–1.9) | 1.1 (0.4–3.7) | |
| Unadjuvanted A(H1N1)pdm09 alone | s | s | 9.7 (3.6–15.8) | 1.1 (0.4–2.9) | 0.6 (0.1–2.6) | |
| Unadjuvanted A(H1N1)pdm09/TIV | s | s | 13.1 (0.0–27.2) | 1.2 (0.2–8.5) | 0.8 (0.0–13.5) | |
*Rates are per 100,000 person-years. A(H1N1)pdm09, pandemic influenza A(H1N1) strain; s, suppressed because of small sample size (n = 1–5) in accordance with the requirements of the data custodian; TIV, trivalent influenza vaccine.
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