US News, CEO's interview about H7N9: major danger with common vaccines
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."
Eggs-grown vaccines for H7 virus family? poor responses...
"Large vaccine dose still ineffective
But studies with previous H7 vaccines have shown poor responses in healthy adults who get a total of 180 micrograms of vaccine divided into two 90 microgram doses, said Michael Osterholm, director of the Center for Infectious Diseases Research and Policy at the University of Minnesota.
That means that even with 12 times the dose people get for seasonal flu, healthy adults don't get a great response to the vaccine. "
""In all cases where these vaccines were trialed, it was found that the vaccines were poorly immunogenic," said Nancy Cox, the virologist who heads the influenza branch at the U.S. Centers for Diseases Control in Atlanta."