The Quint Fit– June 13, 2019. Co-author and CDDEP director, Ramanan Laxminarayan said, “Hib vaccination is a critical component of the pentavalent vaccine, which was introduced in 2011. Although we tend to focus on short term consequences of immunization, this study shows that the effect of Hib vaccination on schooling and cognitive development can be significant. Denying children vaccines is effectively denying them access to these benefits that persist through their lives.”