Flu vaccine grown in insect cells

The technique may speed up production

Scientists have made an experimental - and apparently effective - flu vaccine inside insect cells.

They hope the technique could provide a way to produce vaccine quickly and in volume in the event of a flu pandemic.

At present flu vaccine is produced in hens' eggs, but this is time-consuming, and each egg can only produce one dose of vaccine.

The University of Rochester study appears in the Journal of the American Medical Association.

Scientists believe it is inevitable that the world will face a flu pandemic in the future.

Rapid development, production and distribution of a vaccine will be key to saving lives.

Researcher Professor John Treanor said: "Eggs can be very cumbersome to work with.

"When you need hundreds of millions of fertilized eggs, you're dealing with a whole host of agricultural issues, as well as scientific concerns regarding the flu virus itself.

"Flu viruses can be temperamental, and it's not always an easy matter to get the virus to grow as you want in eggs."

The researchers tested a vaccine called FluBIOk, which relies on a virus which normally infects insects known as baculovirus to churn out its key components.

Promising trials

Tests on 460 volunteers showed nobody who received a 135 microgram dose of the vaccine went on to develop the three strains of flu thought to pose the biggest threat when the study was conducted in the winter of 2004-2005.

The researchers estimate that using insect cells rather than eggs to manufacture the vaccine could slice up to two months off a process that at present takes about six months to produce enough supplies to protect the US public.

They also argue that not relying on chicken eggs might also be advisable in case a bird flu pandemic hits chicken flocks hard.

In addition, a live flu virus is needed when growing vaccine in eggs, a danger when working with a potent bird-flu strain.

Another potential advantage of FluBIOk is that, unlike other flu vaccines, it does not contain neuraminidase, an enzyme that allows a flu virus to replicate and spread.

Professor John Oxford, an expert in virology at London's Queen Mary College School of Medicine, said other researchers were exploring similar techniques for producing flu vaccines.

He said two groups had used mammalian cells, while another was experimenting with the use of plants.

"Using eggs has been very successful for the last 40 years," he said.

"But if you need to increase supplies quickly in the wake of a pandemic you just can't do that using eggs."

Source : BBC