A newly discovered class of antibodies may provide the basis for a new "universal flu vaccine." Researchers at McMaster University and the Icahn School of Medicine at Mount Sinai in New York, NY, believe that this new flu shot could prevent the problems experienced in the current flu season of the annual flu shot not matching accurately against the predominant influenza strain.
In December 2014, Medical News Today reported that the Centers for Disease Control and Prevention (CDC) was urging "immediate vaccination" for anyone who has not had a flu shot for this season, as the flu season this year was predicted to be especially bad.
However, an increase in circulation of "drift variants" of A H3N2 influenza viruses resulted in the flu shot for this season - which was recommended by the World Health Organization (WHO) in February 2014 - being mismatched against the main circulating strains and was reportedly less effective.
Matthew Miller, senior author of the new study and assistant professor in McMaster's Department of Biochemistry and Biomedical Sciences at the Michael G. DeGroote School of Medicine, explains the advantages of his team's proposed universal flu shot:
"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. This would prevent the occurrence of flu pandemics and poor vaccine efficiency in the case of mismatches, which actually occurred this year."
In the Journal of Virology, Miller and colleagues report their findings on comparing, within the laboratory, 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).
The team initially found the universal vaccine type of antibody to be much less effective at neutralizing influenza than the strain-specific antibodies. However, when the team isolated the universal-type antibodies in their natural setting from human blood, both types of antibodies were found to be comparable in effectiveness.
'Inactivated' vaccine versus 'live-attenuated'
Another finding from the study was that the subtype of antibodies located in the lungs and upper respiratory system are especially effective at neutralizing influenza.
Miller says that this finding "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."
The current flu shot is an "inactivated" vaccine. It consists of virus particles that are grown under controlled conditions and then killed using a detergent. In an "attenuated" vaccine, the virus is kept alive but its virulence is reduced.
Because the virus is alive in the attenuated vaccine, it is able to replicate in the upper respiratory tract without being capable of infecting the lung. As the live virus replicates harmlessly, an immune response is generated.
Miller and colleagues are hopeful that a universal flu vaccine will be a reality within the next 5-7 years.
Recently, MNT reported on a study from Columbia University's Medical Center and Mailman School of Public Health in New York, NY, that found text message reminders improved both first- and second-dose vaccination rates among young children.
Flu vaccine coverage remains low among young children overall. However, children who require two doses of vaccine in one season are at particular risk, the authors of that study observed, as less than half of these children return to receive a second dose after receiving their first.