Follow-up of Immunogenicity of Influenza Virus Vaccine, AdimFlu-S (A/H1N1), in Healthy Volunteers After 6 Months
Follow-up of Immunogenicity of Influenza Virus Vaccine, AdimFlu-S (A/H1N1), in Healthy Volunteers After 6 Months
In the spring of 2009, a recently emerged novel influenza A (H1N1) virus was first identified
 in Mexico and USA and it has continued to spread globally. The rapid global spread of a novel
 influenza A (H1N1) 2009 virus prompted the World Health Organization (WHO), on 11 June 2009,
 to declare the first influenza pandemic in 41 years. In Taiwan, a clinical study to assess
 the immunogenicity and safety of Influenza Virus Vaccine, AdimFlu-S (A/H1N1), in healthy
 volunteers has already been completed. In the previous study, we found that a single 15 mcg
 HA dose of the AdimFlu-S (A/H1N1) vaccine induces a protective immune response in most
 adults, including those > 60 years of age (>70%). Our current study aims to follow-up
 subjects who received Influenza Virus Vaccine, AdimFlu-S (A/H1N1), six months ago. These
 subjects' serum samples were tested for anti-hemagglutinin (HA) antibodies by
 hemagglutination inhibition (HAI). The seroconversion is defined as the post-vaccination
 serum HAI titer had at least 1:40 for subjects who had seronegative pre-vaccination or a
 four-fold or greater increase in HAI titers for subjects who had seropositive pre-vaccination
 serum. The immunogenicity of Influenza Virus Vaccine, AdimFlu-S (A/H1N1), in adults after
 half a year will be analyzed and discussed among the subjects with serum HAI titer had at
 least 1:40 at least 3 weeks after AdimFlu-S (A/H1N1) injection.
Inclusion Criteria:

 -  subjects with serum HAI titer had at least 1:40 at least 3 weeks after AdimFlu-S
 (A/H1N1) injection