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Table 2 Relative risk (RR) of having an adverse pregnancy outcome among OCV recipients compared to that of placebo recipients

From: Safety of a bivalent, killed, whole-cell oral cholera vaccine in pregnant women in Bangladesh: evidence from a randomized placebo-controlled trial

Pregnancy outcome OCV recipients Placebo recipients Crude RR (95% CI, p-value) Adj. RR (95% CI, p-value)
Cases/ Population Rate/1000 Cases/ Population Rate/1000
Pregnant during vaccination (Cohort 1)
 Adverse pregnancy outcome 26/231 112.6 27/234 115.4 0.98 (0.58–1.62, 0.923) 0.97a (0.58–1.61, 0.907)
 Miscarriage 20/231 86.6 22/234 94.0 0.92 (0.51–1.64, 0.780) 0.91a (0.51–1.63, 0.752)
 Stillbirth 6/211 28.4 5/212 23.6 1.21 (0.37–4.13, 0.754) --d
 Preterm delivery 7/207 33.8 12/207 58.0 0.59 (0.22–1.43, 0.255) 0.58a (0.22–1.40, 0.237)
 Low birth weight 20/205 97.6 23/207 111.1 0.88 (0.49–1.55, 0.653) 0.88a (0.49–1.55, 0.656)
Pregnant after vaccination (Cohort 2)
 Adverse pregnancy outcome 39/277 140.8 39/299 130.4 1.08 (0.71–1.63, 0.717) 1.02b (0.67–1.55, 0.930)
 Miscarriage 36/277 130.0 32/299 107.0 1.21 (0.78–1.91, 0.395) 1.15b (0.73–1.81, 0.555)
 Still birth 3/241 12.4 7/267 26.2 0.47 (0.10–1.69, 0.276) -d
 Preterm delivery 12/238 50.4 21/260 80.8 0.62 (0.30–1.22, 0.179) -d
 Low birth weight 19/238 79.8 26/260 100.0 0.80 (0.45–1.40, 0.434) 0.82c (0.46–1.43, 0.477)
  1. a Adjusted for gestational age at vaccination
  2. b Adjusted for time of vaccination prior to pregnancy (included by choice due to biological plausibility), diarrhoea in past 6 months and roof material of household
  3. c Adjusted for diarrhoea in the past 6 months
  4. d Number of cases was not sufficient to perform a multivariable model