One of the biggest challenges to producing flu vaccine lies in the fact that so far, scientists have had to grow it in hens’ eggs. Not only is this process cumbersome and slow, but it is often difficult to get the vaccine to grow as one wishes, and further, each egg only yields enough of the flu virus to make a single dose of vaccine. Additionally, problems could potentially be encountered if the bird flu epidemic spreads to those very flocks that provide eggs that produce the vaccine. Clearly, an alternative to hens’ eggs was necessary.
“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,” said Professor John Treanor. “Flu viruses can be temperamental, and it’s not always an easy matter to get the virus to grow as you want in eggs.”
In response to this problem, researchers announced that they have grown an effective flu vaccine inside insect cells. The vaccine, called FluBIOk, relies on baculovirus, which infects insects, to cause insect cells to produce the key components found on the surface of the influenza virus. Normally, these key components allow the flu virus to bind to human cells prior to infection. However, because the immune system can “see” these surface proteins, they act as antigens, which stimulate the body’s immune system to attack and kill infected cells.
Tests on 460 volunteers showed that no one who received the vaccine later developed any of the three strains of flu contained in the vaccine. These three strains of flu were originally thought to pose the biggest threat when the study was conducted during the winter of 2004-2005 when the vaccine trials were carried out.
not only was the new method effective, but it is possible to remove up to two months off the total time necessary to manufacture a complete flu vaccine by using insect cells instead of hens’ eggs to grow the vaccine. Currently, it takes approximately six months to produce enough vaccine to protect the US public.
“Using eggs has been very successful for the last 40 years,” said Professor John Oxford, an expert in virology at London’s Queen Mary College School of Medicine. “But if you need to increase supplies quickly in the wake of a pandemic you just can’t do that using eggs.”
Cited story (quotes).