Impact of pneumococcal vaccination on antimicrobial resistance profile of pneumococci and respiratory infections amongst Indian children

Objective This study assessed the effect of childhood PCV on the antimicrobial resistance of pneumococci isolated from the nasopharyngeal carriage of healthy infants and risk of respiratory infections during first 18 months of life. Methods The study used samples from a completed randomized clinical trial on impact of 2-dose and 3-dose schedules of PCV10 and PCV13 on pneumococcal carriage vs PCV-naïve under-five Indian children. A total of 2371 pneumococcal isolates from the primary study were subjected to antimicrobial susceptibility testing using Vitek-2 platform against 14 antimicrobial agents. Results The primary antibiotics demonstrating resistance were Cotrimoxazole (70.22%), Erythromycin (57.44%), Tetracycline (44.41%), and Clindamycin (22.06%). While the proportion of vaccine serotypes (VTs) resistant to at least one antibiotic was lower in the vaccinated group (20.28 % vs. 24.87%, p=0.044), generalized estimating equations adjusting for child-level clustering and time showed no significant difference in any resistance carriage per visit between groups. 6A, 23F, and 19F were the most common resistant vaccine serotypes, while 11A, 35B, 15A, and 15B were the most frequent non-vaccine serotypes. Respiratory episodes per child did not differ significantly between groups (0.91 vs 0.96, p=0.245). There was no significant difference in the hospitalizations for respiratory infection between the vaccinated group (0.06 vs 0.12 per child, p=0.052). Conclusion The study does not demonstrate a significant reduction resistant pneumococcal serotypes carriage among PCV-vaccinated children when accounting for repeated measures. While there was a trend toward reduced hospitalization for respiratory infections, this was not statistically significant.