Intradermal administration of the pneumococcal conjugate vaccine in mice results in lower antibody responses as compared to intramuscular administration

Introduction: Several studies have shown that intradermal vaccination leads to improved immune responses. In addition, lowering vaccine doses will reduce costs and therefore potentially increase cover-age. To determine whether intradermal delivery enhances the antibody responses against the 13-valent pneumococcal conjugate vaccine (PCV13), we compared intradermally and intramuscularly vaccinated mice.Methods: Mice were immunized with PCV13, either intradermally or intramuscularly and CFU-counts in the nasal tissue were determined three or seven days after intranasal colonization with a serotype 4 clin-ical strain. Antibody concentrations against all thirteen polysaccharides were measured in blood and mucosal samples using a fluorescent-bead-based multiplex immunoassay.Results: Antibody levels in both serum and mucosal samples were higher in the intramuscularly vacci-nated group as compared to the intradermally vaccinated group. No protection against S. pneumoniae intranasal colonization was observed for either vaccination route.Conclusions: Intradermal vaccination was inferior to intramuscular immunization in inducing serotype-specific antibodies.(c) 2022 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

Intradermal vaccination was found to be inferior to intramuscular immunization in inducing serotype-specific antibodies against the 13-valent pneumococcal conjugate vaccine (PCV13). The antibody levels in both serum and mucosal samples were higher in the intramuscularly vaccinated group. Neither vaccination route provided protection against nasally colonized S. pneumoniae.