Despite scientists promising to develop long-lasting flu vaccines, we still have to get shots every year in order to get best possible protection against seasonal flu virus. It means that pharmacy industry has to manufacture massive amounts of vaccines every year, which is long and expensive process. However, now scientists at the University of Wisconsin-Madison have created a technology which can make manufacturing of avian influenza pandemic as well as seasonal flu vaccines a quicker and more efficient process.
What is really interesting is that the research that yielded this new technology was paused by the federal government of United States, because of new regulations for how some viruses can be manipulated. Such discoveries show how important these researches are and are just one more argument against such regulations. Science should not be limited by policies, because limited sciences may produce only limited discoveries.
Coming back to the story, it is important to note that currently seasonal flu vaccines are produced using complex processes. In fact, most flu vaccines are manufactured using fertilized chicken eggs. They serve as crucibles to grow vaccine viruses — viruses that are a good match for anticipated seasonal or pandemic flu strains. During the manufacturing process, flu viruses grown in eggs are deactivated with chemicals and purified. At the end of this process the raw material for a vaccine is produced. There are serious disadvantages of such technology. Most obvious is that millions of eggs are required worldwide to make vaccines, which means that avian influenza, affecting birds, can very seriously disturb manufacturing of seasonal flu vaccines.
Since flu virus mutates every year, new vaccines have to be produced every year too. Vaccines against potential pandemic strains of avian influenza are mass produced and stockpiled every few years based on surveillance of the ever-evolving strains of avian flu circulating in fowl worldwide. Avian influenza can strike the flocks that produce eggs needed for vaccine manufacturing, which means that serious outbreaks of avian flu could impede vaccine production. But there are other disadvantages to this manufacturing technology.
Another drawback is that produced vaccines may not be completely effective. In fact, there have been cases of inaccuracy already. The virus, chosen to be as close a match as possible for an anticipated strain of flu, can change during incubation. In 2014-15 flu season this happened and vaccine was less effective due to changes in the circulating virus itself as well as antigenic changes to the vaccine virus propagated in eggs. Most people probably would never think of that, but current flu vaccines are not suitable for everyone, because some people are allergic to eggs.
So we can see that there are some serious problems with current manufacturing process of flu vaccine using eggs. But there are alternatives. Flu vaccines can be manufactured using mammalian cell cultures. However, this technology used to be even less efficient than making vaccines in eggs. But before government imposed a moratorium on a new study in October 2014, scientists managed to describe a new high-yield method of producing flu vaccines. Scientists say that using new methods could help increase production of vaccines from two to ten times.
Not only new technology would avoid the drawbacks of egg-based vaccine production, but it is also more flexible. Flu vaccine production using mammalian cells could be altered or ramped up more easily – scientists say that cell-based vaccine production can be scaled up very quickly. This new technology relies on viruses engineered to replicate more efficiently in mammalian cells. Professor, Yoshihiro Kawaoka, leader of the research team, explained – “we simply looked for strains that grow well in mammalian cells and picked those mutations that contribute to high yield”.
This discovery may help industry to switch from egg-based vaccine production to cell-based vaccine production. Currently in U.S. there is only one company that produces vaccines relying on cell-based manufacturing methods. But if such researches will not face more obstacles from policy makers, in the near future we may have more effective flu vaccines.