Inhaled Pneumococcal Vaccination Method using Aerosolisation in a Paediatric Lamb Model
Anushi E Rajapaksa1,2,4,6 Anne Balloch1, Paul Licciardi1,2, Robert J. Bischof3, Christina Cortez-Jugo2, Magdy Sourial4, Eileen Dunne1, David Piedrafita5, Kim Mulholland1 and David G Tingay1,2,4,6
1Murdoch Childrens Research Institute, Melbourne, VIC Australia
2University of Melbourne, Melbourne, Australia
3 The Ritchie Centre, Hudson Institute of Medical Research Melbourne, Australia
4 Royal Children’s Hospital, Melbourne, Australia
5 Federation University, Melbourne, Australia
6 Royal Women’s Hospital, Melbourne, Australia.
Background: Pulmonary vaccination holds great potential against safeguarding the high- risk pediatric populations from a range of infectious pathogens, including the pneumococcal disease, a major global health burden. We aimed to investigate if protective antibody levels could be induced in a paediatric lamb model using an aerosolized 13-valent pneumococcal conjugate vaccine.
Methods: Aerosolised Prevnar 13® vaccine was administered to six 4-month old term lambs using the Aeroneb Pro® nebulizer via spontaneous breathing. Immunizations were repeated at 3 weeks (secondary) and 6 weeks (tertiary) after the primary immunization, and blood and BALF was sampled prior to immunization and each week after for determination of IgG and IgA antibody levels (1, 3, 4, 5, 6A, 6B, 7F, 9V, 14, 18C, 19A, 19F, and 23F serotypes) using enzyme-linked immunosorbent assays.
Results: Low levels of IgG antibody levels were found for nine serotypes in lambs that received aerosolized pneumococcal vaccination one week after the tertiary immunisation at 1 in 10 dilution. Serotype specific IgA was not detected in pooled pre or post immunisation serum. However there was a small fold increase in pooled BALF for serotype 6B (1.38) and 18C (1.52).
Conclusions: This study provides proof-of-concept for pulmonary vaccination in biologically and clinically relevant sheep infant models. Such technologies would enable safe, simpler and more effective vaccination strategies, given the complexities in traditional approaches of vaccine delivery to infants.