Swine flu vaccination may protect against 1918 Spanish flu
MedWire News: People who have been vaccinated against the 2009 H1N1 (swine flu) influenza virus may also be protected against the lethal 1918 Spanish influenza virus, which killed around 50 million people worldwide in the early twentieth century, say researchers.
"While the reconstruction of the formerly extinct Spanish influenza virus was important in helping study other pandemic viruses, it raised some concerns about an accidental lab release or its use as a bioterrorist agent," said lead researcher Adolfo Garcia-Sastre, from Mount Sinai School of Medicine in New York, USA.
"Our research shows that the 2009 H1N1 influenza vaccine protects against the Spanish influenza virus, an important breakthrough in preventing another devastating pandemic like 1918."
The researchers studied three groups of mice that received the 2009 H1N1 influenza vaccine, the seasonal influenza vaccine, or no vaccine at all. After 21 days, all the mice were exposed to a lethal dose of the 1918 Spanish influenza virus.
They found that 14 days after infection most of the mice that received the H1N1 vaccine were still alive, whereas all of the mice in the other two groups had died.
The team then studied two groups of mice that were injected with serum taken from humans before and after vaccination against 2009 H1N1 influenza. Both groups then received a potent dose of the 1918 Spanish influenza virus.
Ten days later, the researchers found none of the mice that received post-vaccination serum had developed signs or symptoms of 1918 Spanish influenza, whereas all of the mice that received pre-vaccination serum had developed symptoms.
They also found that, 2 days after infection with the virus, mice treated with post-vaccination serum demonstrated a 32- to 141-fold reduction in viral burden in the lungs compared with mice that received pre-vaccination serum.
Garcia-Sastre and team conclude in the journal Nature Communications: "The data presented in this study indicate that immunization of humans with the 2009 H1N1-inactivated vaccine or natural infection with the 2009 H1N1 virus will confer protective antibody responses against the 1918 pandemic influenza virus in the general population."
They add: "Moreover, our data will likely affect the development of future biosafety measures and policies for working with the 1918 influenza A virus, as immunization with the current 2009 H1N1 vaccine."
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By Mark Cowen