Researchers develop a strong flu vaccine

Tokyo, January 30: Japanese researchers reported that they have developed a vaccine component that can be used to immunize both birds and mammals from dangerous forms of the flu, including the highly lethal H5N1 avian influenza strain.

According to Tetsuya Uchida, researcher at the National Institute of Infectious Diseases, trials of the vaccine on mice confirmed that it works even if flu viruses mutated. The team inoculated mice implanted with human genesdefine that boost immunity and then infected them with three viruses. The mice showed no symptoms of the illness, and the vaccine suppressed the viruses' ability to multiply.

Dr Uchida stated that the previous vaccines were based on proteins that covered the outer surface of the virus. The new vaccine is based on common types of protein inside the bodies of flu viruses because they rarely change. When the vaccine is injected, immune systemdefine cells attack the cells infected by the virus.

It produces antibodies against the vaccine that remain in the system until they are needed. If a virus is introduced into the system, the antibodies attach to viral particles and remove them before they have time to replicate, preventing or lessening symptoms of the virus.

The researchers examined the proteins of three common influenza strains, the Hong Kong A strain, the Soviet A type, and the dreaded H5N1 bird flu, which experts predict could mutate into a new strain. Influenza that affects humans is caused mostly by the Soviet-A, Hong Kong-A and type B viruses. Dr Uchida said the experiment had been carried out with the type A viruses but was confident that the method should also be effective on the type B.

Dr Uchida stated, “We expect this will also be effective on new variations of the much-feared H5N1 strain in addition to conventional flu viruses.”

The World Health Organization (WHO) warns that millions of people could die worldwide if the avian influenza virus mutates into a form easily transmissible among humans.

Uchida said that the practical application of the new vaccine will take several years. It needs to be verified that the vaccine does not cause any serious side effects in humans. To confirm its safety more tests are required with mice and other animals.

He said, “We’ll investigate what dosage will be safe and effective for humans. I hope the vaccine can be put to practical use as soon as possible.”

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.