Plant-based flu vaccines

New plant technologies are faster and cheaper than the old egg-based systems.

When the H1N1 pandemic was officially declared on April 24 of last year, the first dose took six months to make, meaning no one was treated during the first infection wave that summer. According to the Public Health Agency of Canada, 426 Canadians died from the influenza, and only 41% of the population was ultimately vaccinated, far short of the national target of 70%. Thanks to a $21-million grant from the U.S. Department of Defence, a Quebec biotech company thinks it has found a solution in plant-based vaccines — a technology that reduces the production time for vaccines by almost two-thirds.

The central bottleneck in producing flu vaccine is the 50-year-old method of injecting the virus into the amniotic fluid of a fertilized hen’s egg. The process involves waiting for the virus from the World Health Organization (WHO), finding a strain that can grow well in eggs and making sure the eggs are at the proper level of maturity before incubating them. In the case of H1N1, it took four months before vaccine production could start.

Over at Medicago’s research facility in Quebec City, the company was ready to start making H1N1 vaccine in two weeks after using a much simpler process called recombinant DNA technology. Medicago has patented the process that enabled them to download the genetic sequence for the virus from the Internet, rather than from the strain itself, and clone a strand of DNA to incubate within their plants. In under a month, they produced a vial of H1N1 vaccine.

In the event of another pandemic, “we could be a first-response solution,” says CEO Andy Sheldon.

He says many aspects of the plant-based process are easier, which involves soaking nicotine-free tobacco leaves from Australia in a solution containing the virus’s DNA and incubating them in a greenhouse. Unlike fertilized hens’ eggs, which will hatch if they aren’t used, the leaves are easy to keep in stock. Leaves are also more efficient, each producing 100 vaccinations compared with the two to five doses from each egg. Then there’s cost: Sheldon says setting up a facility to produce plant-based vaccines costs less than a tenth of that by other technologies, including cell-based vaccines being used in European markets.

The Pentagon funding will pay for a new 85,000-square-foot facility in Durham, N.C., and it means Medicago will have the space and resources to move on to Phase 2 of the testing process — seeing if they can produce 10 million vaccinations per month. This could have a significant effect on preventing the spread of a pandemic, considering that according to StatsCan, during the H1N1 outbreak only 11.6 million people were vaccinated.

Scott Halperin, director of the Clinical Trials Research Center (CTRC), a research centre at Dalhousie University that worked with the Public Health Agency during the pandemic, says the only reason egg-based vaccines are still around is that the infrastructure is established. “Egg-based vaccines will disappear for the long term,” he says. “For short and medium term, they’ll be there as the main workhorse as gradual technologies scale up, because the transition cost is difficult for funders.”

The Canadian and U.S. governments have taken different strategies on vaccinations. Halperin says for the past 10 years, Canada has invested heavily in GlaxoKlineSmith, an international pharmaceutical company that produces egg-based vaccines, to make sure they have the capability to immunize all Canadians.

The U.S. government has never prioritized the infrastructure to vaccinate all Americans, but since the H1N1 outbreak, it has decided to put its money toward funding the most advanced technology out there to combat pandemics. Sheldon says this means that in case of a moderate to severe pandemic breaking out, the U.S. would have priority access to Medicago’s plant-based vaccines. He says the Canadian government is renegotiating their pandemic plan in 2011 and would like them to invest in a production facility for Medicago so Canadians could also benefit from the technology.

Halperin says though he would welcome a Canadian facility producing plant-based vaccines, the technology is still in its early stages of development. “You can make the best vaccine in world that’s 100% effective and perfectly safe,” he says. “But for something to be usable, you have to be able to make hundreds of thousands or millions of doses, or it won’t have an effect on the population.”