Hopkins team figures out why respiratory vaccine failed

December 16th, 2008 - 4:21 pm ICT by IANS  

Washington, Dec 16 (IANS) Researchers figured out why a respiratory virus vaccine to inoculate children against the infection instead caused severe respiratory disease. “We have found the root cause of the problem, and in doing so we have uncovered clues that will help us design even safer and more effective vaccines in the future,” said senior investigator Fernando Polack, an infectious disease specialist at Johns Hopkins Children’s Hospital.

The findings could restart work on effective killed-virus vaccines not only for respiratory syncytial virus (RSV) but other respiratory viruses. RSV is a negative-sense, single-stranded RNA virus of the family Paramyxoviridae.

The new findings also debunk a popular theory that the 1966 vaccine was ineffective because the formalin used to inactivate the virus disrupted critical antigens, the substances that stimulate the production of protective antibodies.

Instead, researchers said, the problem occurred when the antibodies created by the vaccine failed to successfully bind to the real virus after exposure to it, thereby incapacitating it, said a Hopkins release.

Like vaccines against influenza and polio, the 1966 formalin-inactivated RSV vaccine produced antibodies, but these turned out to be defective ones with poor virus-binding ability.

These findings were published online in Nature Medicine.

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