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Researcher Sees Universal Flu Vaccine Ahead
The fact that this year’s flu shot is not a good match against this year’s influenza strain is well known, and has happened before.
But now researchers at McMaster University in Ontario, Canada, and at the Icahn School of Medicine at Mount Sinai, New York, say that a universal flu vaccine may be on the horizon, thanks to the recent discovery of a new class of antibodies that are capable of neutralizing a wide range of influenza A viruses.
“Unlike seasonal vaccines, which must be given annually, this type of vaccine would only be given once and would have the ability to protect against all strains of flu, even when the virus mutates,” said Dr. Matthew Miller, an assistant professor in McMaster’s Department of Biochemistry and Biomedical Sciences. “This would prevent the occurrence of flu pandemics and poor vaccine efficiency in the case of mismatches, which actually occurred this year.”
In the study, published January 14 in the Journal of Virology, senior author Miller and his colleagues show that when comparing the potency of an isolated strain-specific flu antibody (the type that current vaccines generate) with an isolated broadly neutralizing flu antibody (the type generated by universal vaccines) in a laboratory setting, the latter have much weaker neutralization activity than have the strain-specific antibodies.
While this sounds worrisome, they also found that when they isolated these antibodies in their natural (polyclonal) setting from human blood, their potencies were comparable. The broadly neutralizing antibodies, however, have the added benefit of being able to neutralize many strains of virus.
While much has been learned about the biology of broadly neutralizing antibodies, the new findings provide the first detailed analyses of their biological activity in natural contexts.
The researchers also showed that the subtype of antibodies that are present in the lungs and upper respiratory system is particularly potent in neutralizing flu.
“This is also very encouraging and provides guidance as to what vaccine would be best for delivering a universal flu vaccine – that is, inactivated versus live-attenuated,” Miller added.
The inactivated vaccine (“flu shot”) consists of virus particles, which are grown in eggs under controlled conditions and are then killed using a detergent-based method.
The attenuated vaccine, on the other hand, was created by reducing the virulence of the pathogen while keeping it viable or “live.” Attenuation allows the virus to replicate harmlessly in the upper respiratory tract so that an immune response can be generated, but renders it unable to infect the lungs, where disease normally occurs.
Miller said he is optimistic that a universal flu vaccine could become a reality within the next 5 to 7 years.
Source: McMaster University; January 15, 2015.