Advertise With UsAdvertise on our extensive network of industry websites and newsletters.
Get the PBR newsletterSign up to our free email to get all the latest PBR
news.When tested in mice and ferrets, experimental vaccines based on live, weakened versions of different strains of the H5N1 avian influenza virus were well-tolerated and protected the animals from a deadly infection with naturally occurring H5N1 flu viruses.
Subscribe to our email newsletter
The findings are also encouraging, the researchers say, because they demonstrate the ability to create a vaccine based on one particular strain of the H5N1 flu virus that could potentially protect against different emerging H5N1 flu strains.
The study was the result of a cooperative R&D agreement between the National Institute of Allergy and Infectious Diseases and MedImmune.
“This is an excellent example of the NIH and industry working together to find scientific solutions to potential public health problems,” said NIH Director Dr Elias Zerhouni. “Developing a vaccine that could protect against a potential influenza pandemic is a top priority for all of us.”
There have been 244 confirmed human cases of H5N1 infection and more than half of those were fatal, according to the World Health Organization (WHO). Public health officials remain concerned that the H5N1 virus will evolve to become easily transmissible among people, potentially sparking an influenza pandemic, because humans have no pre-existing immunity to the H5N1 viruses.
The NIAID and MedImmune research team created three vaccines by combining modified proteins derived from virulent H5N1 flu viruses with proteins from an artificially weakened (attenuated) flu strain. The virulent H5N1 viruses were isolated from human cases in Hong Kong in 1997 and 2003, and Vietnam in 2004. The attenuated flu vaccine strain, which also serves as the basis for MedImmune’s FluMist influenza vaccine, was lab-grown in progressively colder temperatures (“cold-adapted”) to prevent the resulting vaccine viruses from spreading beyond the relatively cool upper respiratory tract.
Researchers said the next step would be to evaluate in people the safety and immune response induced by these vaccines to see if they produce cross-reactive antibodies that are likely to protect against different H5N1 viruses.