A new form of avian flu vaccine could soon be available to combat the H5N1 virus in the event of a global pandemic, doctors said in Taipei yesterday. The results of a phase III study of the immunogenicity of an H5N1 pre-pandemic influenza vaccine were presented yesterday at the Annual Meeting of Taiwan Society of Pulmonary and Critical Care.
Led by Yang Pan-chyr (楊泮池), dean of National Taiwan University College of Medicine, Taiwan was one of the four Asian countries to participate in the research study.
The team sought to determine whether a new form of avian flu vaccine with an adjuvant added would be more effective than current ones, said Chang Shan-chwen (張上淳), a professor and physician of infectious diseases at National Taiwan University Hospital.
Four hundred healthy Taiwanese between 18 and 58 years of age participated in the study, which has continued for more than a year, Chang said.
Three hundred and twenty people were inoculated with the vaccine with an AS03 adjuvant, while 81 acted as the control group and were inoculated with an adjuvant-free vaccine.
The results showed that more than 90 percent of those who were given the vaccine with an AS03 adjuvant developed immunity against the H5N1 virus.
Even if the virus had developed into a variant strain, 45.6 percent of people retained their immunity, Chang said.
“Because we are not sure if the H5N1 strain would develop into a variant strain capable of sparking a pandemic by human-to-human transmission, it is critical that the flu vaccine provide immunity against different strains,” he said.
In the event that H5N1 caused a pandemic, 45.6 percent of those vaccinated would still be immune to the new strain, which would aid in controlling the disease during the four to six weeks it would take for a new vaccine targeting the new strain to be developed, he said.
Clinical trial data also showed that by using the AS03 adjuvant, only 3.8 micrograms of antigen would be necessary to develop immunity compared to the 15 micrograms currently required for seasonal flu vaccines.
This means that “more people would be able to benefit from the vaccine,” Chang said.