Most influenza viruses mutate to become immune to vaccines, but this does take a toll on the virus and weakens their ability to replicate and spread from person to person.
In a study published in Nature Communications, the H7N9 virus was shown to resist anti-viral drugs while retaining its ability to cause severe infections in patients, despite undergoing genetic mutations.
"Our study underscores the need to develop a bigger arsenal of antiviral drugs and vaccines, which will allow us to outsmart the influenza virus," said Dr. Nicole Bouvier, assistant professor at the Icahn School of Medicine at Mount Sinai.
Researchers found that the virus retained its ability to replicate in human respiratory cells. Compared to non-resistant strains, both showed comparable human-to-human transmission, indicating that the virus' ability to transmit did not increase. While the H7N9 virus has shown limited ability to transmit from human to human, the same was seen in animal models as well.
"Transmission was inefficient for both of the H7N9 viruses that we tested in our experiments," said Dr. Bouvier. "But surprisingly, transmission of the drug-resistant virus was no less efficient than that of the drug-sensitive version."
The virus has so far infected 135 people and has caused 44 deaths so far. Tamiflu and Relenza are commonly used drugs against influenza viruses, but no vaccine has been developed to prevent H7N9.