The US Food and Drug Administration (FDA) has approved the first flu vaccine grown using insect cells in culture. The method does not require the use of live animals including insects.
This is exciting because the majority of flu vaccines are currently prepared using live, fertilised chicken eggs and this new cell culture technique could now replace this. In chicken egg-based vaccine production, holes are drilled through egg shells and the influenza virus is injected into the fluid that surrounds the growing chicken embryo. The virus infects the unborn chick and begins to multiply in the fluid. After several days of incubation, the eggs are moved to a fridge in order to chill the growing chicks so much that they die. The shells are then cracked open and the virus is removed, purified and used to make the vaccine while the unborn chicks are left to die and thrown away. According to the US Department of Health and Human Services, in order to produce 300 million doses of vaccine, 900 million eggs would be needed.
This January, the FDA announced that it has approved a cell-based vaccine called FlublokTM. To produce this vaccine, cells are taken from a continuous (immortal) line of expressSF+ cells that were isolated from the ovaries of fall armyworms (a type of caterpillar) way back in the 1970’s. They are genetically altered using recombinant DNA technology to make large amounts of protein called hemagglutinin (HA), which is the active ingredient in all inactivated flu vaccines.
Another cell-based flu vaccine called Flucelvax (manufactured by Novartis)- produced in dog kidney cells from another continuous cell line derived from a dog in the 1950s- was granted FDA approval in November 2012.3 Both cell lines can also be grown in serum-free media avoiding the use of foetal bovine serum which is derived from unborn calves killed in the slaughterhouse.
As well having the potential to save millions of animals, cell-based flu vaccines can be made much faster than egg-based vaccines, which is an advantage in case of an epidemic. Due to these promising developments in the USA, we anticipate that a cell-based vaccine will be available in the UK in the very near future.