Modeling Possible Inclusion of Pneumococcal Conjugate Vaccine into the National Immunization Program for Infants in India

Estimation of baseline IgG antibody levels to 23 pneumococcal vaccine-type capsular polysaccharides in healthy vaccine naïve Indian adults

Since immunological responses to pneumococcal vaccines are assessed by a fold-increase in antibody levels relative to pre-immunization levels, it is therefore critical to determine baseline antibody levels to establish putative threshold as a measure of normal response. Herein, for the first time, we measured baseline IgG antibody levels in 108 healthy unvaccinated Indian adults using WHO-recommended ELISA. Median baseline IgG concentration ranged between 0.54 µg/mL to 12.35 µg/mL. Highest levels of baseline capsule polysaccharide (cPS)-specific IgG were found against types 14, 19A, and 33F. Whereas, lowest baseline IgG levels were observed against types 3, 4, and 5. Overall, ∼79 % of study population had median baseline IgG levels ≥1.3 µg/mL against 74 % of cPS's. Substantial baseline antibody levels in unvaccinated adults were observed. The study would be critical in bridging gaps in baseline immunogenicity data and may offer a valuable foundation for evaluating immune response of Indian adults to pneumococcal vaccination.

Estimating the Public Health and Economic Impact of Introducing the 13-Valent Pneumococcal Conjugate Vaccine or 10-Valent Pneumococcal Conjugate Vaccines into State Immunization Programs in India

Introduction

Although the pneumococcal conjugate vaccine (PCV) has been introduced into select state immunization programs (SIPs) in India, many children remain unvaccinated. Recently, India’s Advisory Committee on Vaccines & Immunization Practices recommended PCV on the pediatric immunization schedule nationally. This study estimates the public health and economic impact of introducing either Pfizer’s 13-valent PCV (PCV13-PFE), GlaxoSmithKline’s 10-valent PCV (PCV10-GSK), or Serum Institute of India’s 10-valent PCV (PCV10-SII) into every pediatric SIP.

Methods

A model was developed to predict the disease cases, deaths, and costs associated with implementing PCV13-PFE, PCV10-GSK, or PCV10-SII in SIPs compared to no vaccination program across a 5-year period (2021–2025). State and national-level uptake rate and clinical and economic input parameters were collected from published literature. Disease outcomes included invasive pneumococcal disease, inpatient and outpatient pneumonia, and otitis media. Costs were estimated as vaccine-related costs and direct medical costs incurred to the healthcare system. Results were reported by individual state and aggregated nationally.

Results

Estimated over 5 years, implementing PCV13-PFE in SIPs could avert 12.1 million cases and save 626,512 lives among children under 5 years old compared to no vaccination. This corresponds to net national cost savings of over $1.0 billion. Both lower-valent PCVs are estimated to provide less economic savings than PCV13-PFE inclusive of vaccine-related costs. Compared with PCV13-PFE, implementing PCV10-GSK or PCV10-SII nationally is estimated to have a smaller public health impact, with PCV10-GSK averting 8.4 million cases (436,577 deaths) and PCV10-SII preventing 10.3 million cases (531,545 deaths) in India compared to no vaccination, respectively.

Conclusion

Implementation of PCV13-PFE throughout India is estimated to provide greater public health and economic benefits than PCV10-GSK or PCV10-SII SIPs. Our analysis highlights the substantial disease cases, deaths, and health system cost savings that may be realized from implementing PCV programs throughout India.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40121-021-00498-4.