Table 2.

Maternal influenza vaccine efficacy against first episodes of laboratory-confirmed influenza in infants younger than 6 months born to women vaccinated at any time prepartum or 14 or more days prepartum

	Born to women vaccinated at any time prepartum									Born to women vaccinated ≥14 days prepartum
	TIIV group (n=2064)				MCV group (n=2041)					TIIV group (n=1886)				MCV group (n=1869)
	By month		Cumulative		By month		Cumulative			By month		Cumulative		By month		Cumulative
	Days of follow-up	Cases*	Days of follow-up	Cases*	Days of follow-up	Cases*	Days of follow-up	Cases*	Cumulative vaccine efficacy (95% CI)	Days of follow-up	Cases*	Days of follow-up	Cases*	Days of follow-up	Cases*	Days of follow- up	Cases*	Cumulative vaccine efficacy (95% CI)
<1 month	61 254	0 (0·0)	61 254	0 (0·0)	60 719	6 (0·10)	60 719	6 (0·10)	100%(15·8 to 100)	55 981	0 (0·00)	55 981	0 (0·00)	55 602	5 (0·09)	55 602	5 (0·09)	100% (−8·4 to 100)
1 month	60 251	2 (0·03)	121 505	2 (0·02)	59 562	3 (0·05)	120 281	9 (0·07)	78·0% (−6·3 to 97·7)	55 181	2 (0·03)	111 162	2 (0·02)	54 637	3 (0·05)	110 239	8 (0·07)	75·2% (−24.2 to 97)
2 months	58 886	4 (0·07)	180 391	6 (0·03)	58 675	10 (0·17)	178 956	19 (0·11)	68·7%(18·4 to 89·8)	53 979	3 (0·06)	165 141	5 (0·03)	53 764	8 (0·15)	164 003	16 (0·10)	69·0%(11·.3 to 91·1)
3 months	57 468	5 (0·09)	2378 59	11 (0·05)	57 017	15 (0·26)	235 973	34 (0·14)	67·9%(35·1 to 85·3)	52 638	4 (0·08)	217 779	9 (0·04)	52 212	14 (0·27)	216 215	30 (0·14)	70·2%(35·7 to 87·6)
4 months	55 600	14 (0·25)	293 459	25 (0·09)	54 913	24 (0·44)	290 886	58 (0·20)	57·3%(30·6 to 74·4)	50 893	12 (0·24)	268 672	21 (0·08)	50 200	23 (0·46)	266 415	53 (0·20)	60·7%(33·8 to 77·5)
5 months	48 485	27 (0·56)	341 944	52 (0·15)	47 608	19 (0·40)	338 494	77 (0·23)	33·1%(3·7 to 53·9)	44 434	24 (0·54)	313 106	45 (0·14)	43 539	18 (0·41)	309 954	71 (0·23)	37·3%(7·6 to 57·8)

TIIV=trivalent inactivated influenza vaccine. MCV=quadrivalent meningococcal conjugate vaccine.

^*Incidence per 1000 infant-days of follow-up.