Table 4. Hypothetical TB incidence among 0-14 yrs old population in Japan.^3,9.

Year	With universal vaccination (per 100,000 population)			Without universal vaccination (per 100,000 population)
	Age (year)			Age (year)
	0-4	5-9	10-14	0-4	5-9	10-14
2000	2.3	0.8	1.4	-	-	-
2005	1.8	0.6	1.1	2.7	0.9	1.7
2010	1.4	0.5	0.9	1.7	0.6	1.0

Hypothetical Calculations:

Incidence of TB among the 0-14 yrs children, if universal BCG vaccination were discontinued from the year 2000, was calculated from the formula derived from Rahman et al.⁹ with 10% annual discount for prevention practices, better diagnosis and treatment facilities. On the other hand, future TB incidence, if universal BCG is opted to be continued till 2010, was calculated only by discounting at 5% annual rate.

Example:

Suppose BCG was discontinued from the year 2000. Incidence of TB among the 0-4 year-old children in the year 2010 would be;

=Incidence of TB among the 0-4 years reported for the year 2000/(1-proportion of children vaccinated * vaccine efficacy) X 1/(1+0.1)¹⁰

=23/(1-0.95*0.5) X 1/(1.1)¹⁰

=1.7 per 100,000 population.

In another scenario where BCG would be continued at least up to 2010. Incidence of TB among the 0-4 year-old children in the year 2010 would be;

= Incidence of TB among the 0-4 years reported for tthe year 2000/(1+0.05)¹⁰

=23/(1.05)¹⁰

=1.4 per 100,000 population.