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

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

Pregnancy outcome	OCV recipients		Placebo recipients		Crude RR (95% CI, p-value)	Adj. RR (95% CI, p-value)
Pregnancy outcome	Cases/ Population	Rate/1000	Cases/ Population	Rate/1000	Crude RR (95% CI, p-value)	Adj. RR (95% CI, p-value)
Pregnant during vaccination (Cohort 1)
Adverse pregnancy outcome	26/231	112.6	27/234	115.4	0.98 (0.58–1.62, 0.923)	0.97^a (0.58–1.61, 0.907)
Miscarriage	20/231	86.6	22/234	94.0	0.92 (0.51–1.64, 0.780)	0.91^a (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)	0.58^a (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)	0.88^a (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)	1.02^b (0.67–1.55, 0.930)
Miscarriage	36/277	130.0	32/299	107.0	1.21 (0.78–1.91, 0.395)	1.15^b (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)	0.82^c (0.46–1.43, 0.477)

^a Adjusted for gestational age at vaccination
^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
^c Adjusted for diarrhoea in the past 6 months
^d Number of cases was not sufficient to perform a multivariable model

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