NPC in Indian Children Who Participated in the Alternate PCV Dosing Study

The present study is a longitudinal observational study of children vaccinated with different schedules of PCVs (3+0, 2+1, and 1+1) during a previously conducted randomized clinical trial. It also includes the previous control group that received 2 doses of PCV in the second year of life at the end of the study and a newly added unvaccinated cohort. A total of 771 study participants who completed the follow-up of the parent study were approached at 36 months of age for participation in the present study. Additionally, 115 healthy children of the same age who were not part of the parent study and did not receive PCV were recruited as a control group. Children are followed up six-monthly for nasopharyngeal carriage, and information regarding factors affecting nasopharyngeal carriage is collected.