PLoS ONE (Dec 2010)

Immune protection induced on day 10 following administration of the 2009 A/H1N1 pandemic influenza vaccine.

  • Yizhuo Sun,
  • Chao Bian,
  • Ke Xu,
  • Weibin Hu,
  • Tongyan Wang,
  • Jun Cui,
  • Hongqiang Wu,
  • Zhiyang Ling,
  • Yongyong Ji,
  • Guomei Lin,
  • Lin Tian,
  • Yanyan Zhou,
  • Bingnan Li,
  • Guiyu Hu,
  • Ning Yu,
  • Wenqi An,
  • Ruowen Pan,
  • Paul Zhou,
  • Qibin Leng,
  • Zhong Huang,
  • Xiaowei Ma,
  • Bing Sun

DOI
https://doi.org/10.1371/journal.pone.0014270
Journal volume & issue
Vol. 5, no. 12
p. e14270

Abstract

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The 2009 swine-origin influenza virus (S-OIV) H1N1 pandemic has caused more than 18,000 deaths worldwide. Vaccines against the 2009 A/H1N1 influenza virus are useful for preventing infection and controlling the pandemic. The kinetics of the immune response following vaccination with the 2009 A/H1N1 influenza vaccine need further investigation.58 volunteers were vaccinated with a 2009 A/H1N1 pandemic influenza monovalent split-virus vaccine (15 µg, single-dose). The sera were collected before Day 0 (pre-vaccination) and on Days 3, 5, 10, 14, 21, 30, 45 and 60 post vaccination. Specific antibody responses induced by the vaccination were analyzed using hemagglutination inhibition (HI) assay and enzyme-linked immunosorbent assay (ELISA). After administration of the 2009 A/H1N1 influenza vaccine, specific and protective antibody response with a major subtype of IgG was sufficiently developed as early as Day 10 (seroprotection rate: 93%). This specific antibody response could maintain for at least 60 days without significant reduction. Antibody response induced by the 2009 A/H1N1 influenza vaccine could not render protection against seasonal H1N1 influenza (seroconversion rate: 3% on Day 21). However, volunteers with higher pre-existing seasonal influenza antibody levels (pre-vaccination HI titer ≥1∶40, Group 1) more easily developed a strong antibody protection effect against the 2009 A/H1N1 influenza vaccine as compared with those showing lower pre-existing seasonal influenza antibody levels (pre-vaccination HI titer <1∶40, Group 2). The titer of the specific antibody against the 2009 A/H1N1 influenza was much higher in Group 1 (geometric mean titer: 146 on Day 21) than that in Group 2 (geometric mean titer: 70 on Day 21).Recipients could gain sufficient protection as early as 10 days after vaccine administration. The protection could last at least 60 days. Individuals with a stronger pre-existing seasonal influenza antibody response may have a relatively higher potential for developing a stronger humoral immune response after vaccination with the 2009 A/H1N1 pandemic influenza vaccine.