Table 2.
Product used and adjusted risk measures in observational studies reporting on the association of maternal influenza vaccination and preterm deliveries
| Reference | Product | Analyses | Results |
|---|---|---|---|
| Nordin, et al. 2014 34 | Seasonal not containing A/H1N1pdm09 | OR calculated by conditional logistic regression. Vaccinated women were matched with unvaccinated by propensity score (1:1). | aOR: 0.97 (0.93 to 1.02), aOR: 0.99 (0.91 to 1.08) 1st trimester, aOR: 0.96 (0.90 to 1.03) 2nd trimester, aOR: 0.98 (0.87 to 1.09) 3rd trimester |
| Adedinsewo, et al. 2013 49 | Seasonal not containing A/H1N1pdm09 | OR adjusted for covariates identified during the control period. | aOR: 0.83 (0.60 to 1.17) |
| Dodds, et al. 2012 44 | Seasonal not containing A/H1N1pdm | OR calculated by logistic regression with adjustment for potential confounders. | aOR: 0.84 (0.69 to 1.02) |
| Omer, et al. 201133 | Seasonal not containing A/H1N1pdm09 | OR calculated by logistic regression with adjustment for potential confounders. Stratification by influenza circulation. | aOR: 0.83 (0.55 to 1.26) overall period, aOR: 0.27 (0.08 to 0.86) period with widespread influenza activity |
| Munoz, et al. 200535 | Seasonal not containing A/H1N1pdm09 | Vaccinated women matched with unvaccinated (1:3.5) for maternal age at delivery, month of delivery, and type of insurance. | OR: 0.67 (0.32 to 1.32) |
| Legge, et al. 2014 39 | Seasonal containing A/H1N1pdm09 | OR calculated by logistic regression adjusted for potential confounding variables found to be associated with vaccination in a backward stepwise regression model. | aOR: 0.75 (0.60 to 0.94) |
| Chambers, et al. 2013 46 | A/H1N1pdm09 with (28%) or without seasonal (2009/10) or seasonal containing A/H1N1pdm09 (2010/12) | HR calculated by Cox regression with vaccination as a time-varying exposure adjusted for potential confounding variables. | aHR: 3.28 (1.25 to 8.63) overall anytime in pregnancy, aHR: 3.32 (1.20 to 9.18) 2009/10 season anytime in pregnancy, aHR: 2.25 (0.88 to 5.75) 20010–12 seasons anytime in pregnancy |
| Louik, at al. 2013 37 | A/H1N1pdm09 with or without seasonal (Oct 2009-Jul 2010) or seasonal containing A/H1N1pdm09 (Aug 2010–Jul 2011) | HR calculated by Cox regression with vaccination as a time-varying exposure. Vaccinated women were matched with unvaccinated by propensity score. | aHR: 1.03 (0.50 to 2.10) overall anytime in pregnancy, aHR: 2.82 (1.16 to 6.86) 2009/10 season overall anytime in pregnancy, aHR: 2.17 (0.65 to 7.20) 2009/10 season monovalent anytime in pregnancy, aHR: 0.22 (0.06 to 0.83) 20010/11 season anytime in pregnancy |
| Cantu, et al. 2013 47 | A/H1N1pdm09 with or without seasonal (2009/10) or seasonal containing A/H1N1pdm09 (2010/12) | RR adjusted for potential confounders by multivariable logistic regression. | aRR: 1.2 (0.9 to 1.6) |
| Richards, et al. 2013 30 | A/H1N1pdm09 with or without seasonal | OR calculated by logistic regression adjusted for potential confounding variables. | aOR: 0.63 (0.47 to 0.84) |
| Fell, et al. 201243 | A/H1N1pdm09 with (8.5%) or without seasonal | RR calculated by logistic regression with adjustment for potential confounders. | aOR: 0.95 (0.88 to 1.02) |
| Cleary, et al. 2014 45 | A/H1N1pdm09 | OR calculated by logistic regression adjusted for potential confounding variables. | aOR: 0.72 (0.58 to 0.89) |
| Beau, et al. 2014 48 | A/H1N1pdm09 (93% unadjuvanted vaccine, Panzema) | HR calculated by Cox regression with vaccination as time-varying exposure. Adjusted measures using conditional forward stepwise regression. Vaccinated women were matched with unvaccinated (1:2). | aOR: 0.82 (0.64 to 1.06) |
| Ludvigsson, et al. 2013 36 | AS03-A/H1N1pdm09 (Pandemix) | OR calculated by logistic regression with adjustment for potential confounders. | aOR: 0.99 (0.89 to 1.10) |
| Haberg et al. 2013 10 | AS03-A/H1N1pdm09 (Pandemix) | HR calculated using gestational age as the time metric variable and adjusted for potential confounders. | aHR: 1.0 (0.93 to 1.09) |
| Kallen, et al. 201241 | AS03-A/H1N1pdm09 (Pandemix) | OR adjusted by the Mantel–Haenszel method for potential confounders. | aOR: 0.86 (0.77 to 0.96), aOR: 0.95 (0.85 to 1.08) 1–19 week of gestation, aOR: 1.09 (0.94 to 1.26) 20–26 week of gestation, aOR: 0.81 (0.69 to 0.96) 27–36 week of gestation |
| Pasternak, et al. 201231 | AS03-A/H1N1pdm09 (Pandemrix) | OR calculated by logistic regression. Vaccinated women were matched with unvaccinated by propensity score (1:1). | aOR: 1.32 (0.76 to 2.31) 1st trimester, aOR: 1.0 (0.84 to 1.17) 2nd and 3rd trimesters |
| Van der Maas, et al. 2015 27 | 2-doses MF59-A(H1N1)pdm (Focetria) | ORs calculated by logistic regression adjusted for potential confounding variables. | aOR: 0.98 (0.59 to 1.62) |
| Rubinstein, et al. 2013 29 | MF59-A/H1N1pdm09 (Focetria) | OR calculated by logistic regression adjusted for potential confounders. | aOR: 0.79 (0.69 to 0.90) |
| Heikkinen, et al. 2012 42 | MF59-A/H1N1pdm09 (Focetria) | OR calculated by logistic regression with stepwise approach for potential confounders and proportional hazard models that adjust for differential follow-up time. | aOR: 0.75 (0.55 to 1.01), adjusted proportional hazard: 0.69 (0.51 to 0.92) |
aOR: adjusted odds ratio; aHR: adjusted hazard ratio; aRR: adjusted risk ratio.