WASHINGTON — For a half-century, flu vaccine has been brewed in chicken eggs. The government issued new guidelines Thursday that promise to spur a more modern recipe: using vats of cells instead.
Revamping the nation’s somewhat quaint flu-shot production still is years away. But the Bush administration has awarded manufacturers tens of millions of research dollars to try — because if the Asian bird flu or some other influenza super-strain sparks a worldwide epidemic, today’s factories couldn’t brew vaccine fast enough to help.
“Once you run out of eggs, you can’t make more vaccine. But if you have cells banked, you can always make more vaccine,” explained Philip Krause, the Food and Drug Administration’s deputy director of viral vaccines.
FDA’s guidelines come just two days after the nation’s leading flu-shot maker, Sanofi Pasteur, opened its first safety study of a cell-based influenza vaccine. Researchers in South Carolina and Missouri will enroll 100 healthy volunteers, half of whom will get the regular flu shot and the other half Sanofi’s experimental cell-based one.
Banks of cells taken either from animals or people already are used to make numerous medical products, including a host of vaccines that protect against such diseases as polio and chickenpox. Already, manufacturers must follow rules to guard against contamination of the cells and other safety issues.
But cell-based manufacturing is becoming more sophisticated, even as flu vaccine makers explore switching to so-called cell cultures, too. So FDA’s guidelines, the first update since 1993, are aimed at all manufacturers, explaining state-of-the-art options for ensuring the safety and purity of different cell-culture types.
“The advice will assist manufacturers ... both to develop new and better vaccines and to boost production capacity, making us better prepared for the threat of a future influenza pandemic and other infectious diseases,” said Dr. Jesse Goodman, FDA’s chief of biologic products.
“Anything that helps us understand what the FDA will require as part of the licensure process is helpful. The earlier in the development process that we know about it, the better,” said Sanofi spokesman Len Lavenda, whose company entered a five-year government contract last year to speed development of cell-based flu shots.
Today’s egg-based flu vaccine does a good job. Some 100 million doses are expected this fall, and flu specialists are urging more people than ever to get inoculated.
But it requires growing flu virus inside tens of millions of eggs from specially raised hens months before the fall vaccination season begins. A cell-based system’s chief improvement: Faster production if a new flu strain suddenly appeared, because makers wouldn’t be limited by availability of the special eggs.