As the H7N9 bird flu outbreak continues to worsen in Asia, with the first case outside China confirmed in Taiwan Thursday and the World Health Organization confirming the strain is "unusually dangerous for humans," vaccine makers say it will take up to six weeks for the first vaccines to be developed for the strain.
At a press briefing Wednesday, Keiji Fukuda, the WHO's assistant director for health security, said the situation in China "remains complex and difficult and evolving," as a team of experts attempts to identify the source of the strain.
Chinese officials suspect there may be cases of human-to-human transmission, which would be necessary for the outbreak to rise to pandemic levels. So far, the strain has infected 108 people, 22 of whom have died. If the strain proves to be a candidate for a pandemic outbreak, it might be a while before health professionals have a vaccine to protect against the strain, according to Joseph Kim, president of Inovio, a California-based company that is currently in the initial stages of developing an H7N9 vaccine.
"The fastest we'd be able to have a vaccine to test in animals for H7N9 would probably be 4-6 weeks from now," he says. "We're partnering with collaborators to get access to the virus in a highly protected lab environment."
Under normal circumstances, the path from animal testing to "small scale human tests" to full approval takes another couple months "in an accelerated path," Kim says. But in the case of a pandemic, the animal testing stage is sometimes skipped and the vaccine is immediately used to treat humans.
"In a pandemic setting, you can potentially grow the vaccine and use them without human testing in emergency cases," Kim says.
The traditional method of creating vaccines uses chicken eggs to create doses of the vaccine, which proved troublesome while scientists were trying to create an H5N1 bird flu vaccine in 2009. Kim warns that researchers might have similar problems creating an H7N9 vaccine because both H5N1 and H7N9 infect chickens.
"The H5N1 viruses proved very pathogenic to the vaccine grown in eggs, so we had huge trouble growing them to make the vaccines," he says. "H7N9 could be similar – if we're making conventional pandemic flu vaccines using eggs, we might face challenges."