Table 2.

Occurrence of Blood Culture-Confirmed Typhoid Fever and Efficacy of Typhoid Conjugate Vaccine (TCV).

Variable	TCV			MenA Vaccine			Efficacy of TCV	Absolute Risk Reduction	Number Needed to Vaccinate††
	Participants (total follow-up time)	Cases	Incidence	Participants (total follow-up time)	Cases	Incidence
	no. (person-years)		no. of cases/100,000 person-years (95% CI)	no. (person-years)		no. of cases/100,000 person-years (95% CI)	percent (95% CI)	per 1000 (95% CI)	no. (95% CI)
Intention-to-treat population (from time of vaccination)
Age Group
Total participants	14,069 (25,577)	12	46.9 (24.2–82)	14,061 (25,493)	62	243.2 (186.5–311.8)	80.7 † (64.2–89.6)	3.6 § (2.4–4.8)	277.8 (208.3–416.7)
<5years	5058 (9086)	5	55 (17.9–128.4)	5179 (9305)	20	215 (131.3–332)	74.4 (31.7–90.4)	2.9 (1–4.8)	344.8 (208.3–1000)
≥5years	9011 (16,491)	7	42.5 (17.1–87.5)	8882 (16,188)	42	259.5 (187–350.7)	83.7 (63.6–92.7)	4 (2.4–5.5)	250 (181.8–416.7)
Per-protocol population (14 days after vaccination)
Age Group
Total participants	13,945 (25,323)	10	39.5 (18.9–72.6)	13,937 (25,239)	61	241.7 (184.9–310.5)	83.7 † (68.1–91.6)	3.7 § (2.5–4.8)	270.3 (208.3–400)
<5years	5044 (9057)	5	55.2 (17.9–128.8)	5158 (9261)	20	216 (131.9–333.5)	74.4 (31.8–90.4)	2.9 (1.0–4.8)	344.8 (208.3–1000)
≥5years	8901 (16,267)	5	30.7 (10–71.7)	8779 (15,978)	41	256.6 (184.1–348.1)	88 (69.7–95.3)	4.1 (2.6–5.6)	243.9 (178.6–384.6)

^*CI denotes confidence interval, and MenA group A meningococcal.

^†p-value <0.001

^§p-value <0.001

Absolute risk reduction (=risk in MenA – risk in TCV) is the total reduction in risk of blood culture-confirmed typhoid fever that results from TCV vaccination.

^††The number of children needed to be vaccinated to prevent one case of blood-culture confirmed typhoid fever.