TOKYO: Researchers in Japan said Thursday they had developed a flu vaccine that works against multiple viruses and could prevent a deadly pandemic of bird flu mutations.
The research team has tested the vaccine on mice implanted with human genes, confirming that it works even if flu viruses mutate, according to Tetsuya Uchida, researcher at the National Institute of Infectious Diseases.
Currently flu vaccines use a protein covering the surface of viruses but the protein frequently mutates to make the vaccines ineffective.
Effective against bird flu?
The newly developed vaccine is based on common types of protein inside the bodies of flu viruses as they rarely change, Uchida said. The viruses were the Soviet-A and Hongkong-A along with the deadly H5N1 strain of bird flu.
“We expect this will also be effective on new variations” of the much-feared H5N1 strain in addition to conventional flu viruses, he said.
The World Health Organisation (WHO) warns that millions of people could die worldwide if the avian influenza virus mutates into a form easily transmissible among humans.
Uchida said it would likely take several years to put the vaccine to practical use as the research team needs to confirm the vaccine’s safety with further experiments on mice and possibly larger animals before tests on humans.
The study is being jointly conducted by researchers from the national institute, Hokkaido University, Saitama Medical University and NOF Corp., a chemicals company based in Tokyo.
Influenza that affects humans is caused mostly by the Soviet-A, Hongkong-A and type B viruses, according to experts. Uchida said the experiment had been done with the type A viruses but the method should also be effective on the type B.
Many people who were affected by the Soviet-A strain in Japan this winter were found to be resistant to widely used flu medicine Tamiflu, Japan’s health ministry has warned.
Tamiflu has been controversial in Japan after authorities said children jumped off buildings or ran into traffic after taking it. But authorities have found no direct link between the drug and the abnormal behaviour.
Similar vaccination studies on attacking the inside of the virus body rather than its surface are also under way abroad, including at Oxford University in Britain, Uchida said.
About 250 people have died of avian flu since 2003, according to the WHO. Indonesia is the country worst-hit by avian influenza with 115 deaths officially recorded since 2003.
Five deaths have been reported in China this month, compared with just three in the whole of 2008, alarming health officials.
China is considered one of the nations most at risk of bird flu epidemics because it has the world’s biggest poultry population and many chickens in rural areas are kept close to humans.
Human victims consist mostly of people in close contact with sick birds. There is no evidence so far that the deadly strain of bird flu has mutated into a form that could set off a pandemic.