Abstract
BackgroundThe effect of previous natural pandemic H1N1 (H1N1 pdm09) influenza infection on the immunogenicity to subsequent inactivated influenza vaccination in children has not been well studied. We aimed to evaluate the effect of H1N1 pdm09 natural infection and vaccination on the immunogenicity to subsequent 2010-2011 seasonal inactivated influenza vaccination in children.MethodsFrom October 2010 to May 2011, we conducted an open-label, multi-center study in children aged 6 months -18 years in Korea. We measured antibody titers with a hemagglutination-inhibition (HI) assay at baseline, 1 month, and 6 months after vaccination with trivalent split or subunit vaccines containing H1N1 pdm, A/H3N2, and B. The subjects were classified into 4 groups depending on the presence of laboratory-confirmed H1N1 pdm09 infection and/or vaccination in the 2009-2010 season; Group I: vaccination (-)/infection(-), Group II: vaccination (-)/infection(+), Group III: vaccination (+)/infection(-), Group IV: vaccination (+)/infection(+).ResultsAmong the subjects in group I, 47 subjects who had a baseline titer >1:10 were considered to have an asymptomatic infection. They were included into the final group II (n = 80). We defined the new group II as the infection-primed (IP) group and group III as the vaccine-primed (VP) group. Seroconversion rate (57.5 % vs 35.9 %, p = 0.001), seroprotection rate at 6 months after vaccination (70.8 % vs 61.8 %, p = 0.032), and GMT at 1 month after vaccination (129.9 vs 66.5, p = 0.002) were significantly higher in the IP group than in the VP group. In the 9–18 year-old group, seroconversion rate and immunogenicity at 1 and 6 months were significantly higher in the IP group than in the VP group. However in the 1–7 year-old age group, there was no significant difference between the two groups.ConclusionsPrevious H1N1 pdm09 infection appears to have positive effects on immunogenicity of subsequent inactivated influenza vaccines against H1N1 pdm09 in older children.
Highlights
The effect of previous natural pandemic H1N1 (H1N1 pdm09) influenza infection on the immunogenicity to subsequent inactivated influenza vaccination in children has not been well studied
We demonstrated that the immune response induced by natural H1N1 pdm09 infection was superior to that induced by pandemic H1N1 vaccination [8]
We aimed to evaluate the effect of H1N1 pdm09 natural infection and vaccination on the immunogenicity to subsequent 2010–2011 seasonal inactivated influenza vaccination containing the A/California/7/2009 (H1N1)-like strain in children
Summary
The effect of previous natural pandemic H1N1 (H1N1 pdm09) influenza infection on the immunogenicity to subsequent inactivated influenza vaccination in children has not been well studied. We aimed to evaluate the effect of H1N1 pdm natural infection and vaccination on the immunogenicity to subsequent 2010-2011 seasonal inactivated influenza vaccination in children. Most of the solid organ transplant recipients lack long-term humoral and cellular immune responses to influenza virus even after natural H1N1 pdm infection [3]. After primary influenza virus infection, the persistence of influenza virus-specific antibody-secreting cells and development of B-cell memory have been reported. This is probably the associated mechanism of long-lasting protection induced by natural infection [4]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
