Vaccination Index At age 2 m At age 4 m At age 6 m At age 12 m At age 12-24m At age 2 m   0.994* 0.978* 0.630* 0.480* At age 4 m     0.970* 0.630* 0.474* At age 6 m       0.670* 0.520* At age 12 m         0.760* P ≤ 0.05

Table 6: Pearson correlations between the indices of vaccination during the first two years of life.