Hong Kong Med J 2023;29(Suppl 7):S39-40
Influenza ADCC-antibody responses in vaccinated and infected children as a correlate of protection: abridged secondary publication
S Valkenburg, BJ Cowling, NHL Leung
Department of Public Health, The University of Hong Kong, Hong Kong SAR, China
 
 
  1. Pandemic haemagglutinin IgG responses are boosted by recent seasonal vaccination and decline within 1 year and reach baseline by 5 years post-vaccination.
  2. Correlation is strong between FcR binding and antibody-dependent cellular cytotoxicity function, validating the use of multiplex bead approaches to quantify antibody responses.
  3. Vaccination increased IgG1 responses to vaccine and pandemic proteins (HA H3 H1, neuraminidase, nucleoprotein).
  4. Unvaccinated uninfected children had increased H1/09 IgG and FcγRIIIA, compared with unvaccinated children who became infected. This indicates that higher baseline pandemic-specific antibodies coincide with protection.
  5. Antibody diversity is increased by vaccination and infection, but the diversity does not extend to avian influenza viruses.