Immunogenicity and Safety of Pandemic Influenza H5N1 Vaccines in Healthy Adults through Meta-Analysis.

Background: There are sporadic cases and local outbreaks of H5N1 avian influenza virus worldwide every year. The World Health Organization (WHO) has paid close attention to the avian influenza epidemic trend. Avian influenza vaccines (AIV) are considered to be useful when an epidemic occurs. However, the use of AIV for humans is not yet widespread.

Methods: This study assessed the immunogenicity and safety of pandemic influenza H5N1 vaccines with inactivated whole virus, split virus and subunit virus vaccines for healthy adults. We searched the databases of the Cochrane Central Register of Controlled Trials (CENTRAL), Medline, Excerpata Medica Database (EMBASE) and China National Knowledge Infrastructure (CNKI). The data from randomized trials regarding the immunogenicity and safety of AIV with or without different types of adjuvants for healthy adults (with an age range from 18 to 60 years) were collected.

Results: According to this study, the most effective doses of H5N1 AIV ranged from 3.75 µg to 7.5 µg Hemagglutinin (HA) antigen. Aluminium adjuvants were administered with the same vaccine dose as a no-adjuvant group and induced the same immune effects. However, novel adjuvants (MF59 and AS03) were used with a smaller dose of vaccine than the no-adjuvant groups and successfully stimulated the body to produce more effective antibodies.

Conclusion: All of the H5N1 AIV surveyed in this study were well tolerated without serious adverse reactions.