A doctor at the Centers for Disease Control examines specimens in an effort to develop new influenza vaccines
With the first reported death from the 2009 H1N1 flu, or swine flu, in the U.S., the Federal Government and flu-vaccine manufacturers are preparing for the possibility that a new vaccine will be necessary to control the outbreak. Should the call for vaccine production come from health officials, both traditional and newer, faster vaccine-making methods could be employed.
Dr. Richard Besser, acting director of the Centers for Disease Control and Prevention (CDC), said the agency has begun cultivating the seed stock of virus needed for a swine flu vaccine. (The current seasonal flu vaccine would not be effective against the swine flu.) "We're moving forward aggressively so that if a decision is made that we need to rev up production to make that vaccine, we would be ready to do so," he said. (See pictures of thermal scanners hunting for swine flu.)
But even if the CDC's seed stock of virus were to be released to vaccine makers today, it would take the companies anywhere from four to six months before the first inoculation could be ready for public use. That's because flu-vaccine production — whether for swine or seasonal flu — is time-consuming and laborious, requiring vaccine makers to grow millions of copies of the flu virus in chicken eggs, then purify those bugs into a ready-to-inject formula safe for patients. "We are moving things around to accommodate this and getting our raw materials ready and having our scientists ready. We are on alert, waiting on the CDC. We're in daily contact with them," says Donna Cary, spokeswoman for Sanofi Pasteur, which currently makes 50 million doses of the seasonal flu vaccine used in the U.S. each year.
But if and when the CDC gives the go-ahead, companies such as Sanofi will have to do an about-face, scrapping their current vaccine projects to switch to swine flu. Sanofi and other vaccine makers received the seed stock for the upcoming flu season last January and are now in the midst of culturing and purifying that virus for this fall's flu season. Nevertheless, Cary is confident: "We have two plants that both have the capability of producing what the U.S. market demand is for the seasonal and swine influenza vaccine," she says.
History teaches us, however, that it won't be easy. The last time the U.S. recommended nationwide vaccination against a suspected swine flu was in 1976, with less than successful results, to say the least. Under orders from President Gerald Ford, a vaccine was rushed into production and administered to 45 million Americans, at a cost of $135 million. But within weeks, people started developing Guillain-Barré syndrome, a paralyzing immune-system disorder that can result from the vaccine. Some experts estimated the risk of Guillain-Barré as being seven times higher in those who were immunized vs. those who were not. After the immunization program was terminated nine months after it began, government officials paid $90 million in damages to patients who were injured by the vaccine. The widely feared swine flu epidemic never emerged. (Read "5 Things You Need to Know About the Swine Flu Outbreak.")
Much has changed since then. Genetic advances have given researchers entirely new ways of developing vaccines. For example, instead of using the entire virus or bacterium to activate the human immune system, new strategies rely on genetic snippets from infectious bugs, which can trigger immunity without the risk of infection.
At the biotech company Novavax, researchers are testing the use of virus-like particles (VLP), instead of the virus itself, to stimulate a flu immune response. Using this method, a vaccine for the 2009 H1N1 virus could be in production in 10 to 12 weeks, rather than the usual four to six months. "We have made vaccines against multiple flu strains and tested them in humans and gotten relevant and robust immune responses, which checks off the major boxes that the technology works against flu," says Rahul Singhvi, president and CEO of Novavax.
Novavax's strategy involves isolating three proteins from the virus that flag the human immune system, which then churns out neutralizing antibodies against the proteins. These antibodies are robust enough to fight off the actual virus should an immunized person become infected. This is the same way the recently developed vaccine against human papilloma virus, Gardasil, works. "It provides the look and feel of the flu virus but does not have the genetic materials to cause disease," Singhvi says. (Read about the vaccine being prepared in case of a pandemic.)
A VLP vaccine may also prove easier to develop since all it requires is an accurate genetic sequence of three critical virus genes. That could especially help with swine flu, since researchers found back in the 1970s that the virus doesn't grow well in chicken eggs; that could slash the yield and slow production of a potential new vaccine. "As long as we get the genetic sequence of some viral proteins, it doesn't matter where the virus came from — human, swine or bird," says Singhvi. So far, Novavax's shot is still in the testing phase, but its VLP-based vaccines against seasonal and bird flu are providing good results. The company stands ready to try its strategy against swine flu if needed. "The CDC is aware of what we are doing, and we have offered to help both the Department of Health and Human Services and the CDC," says Singhvi.
Other companies are taking an entirely novel approach and hoping to pick off influenza viruses in the nasal passages before they get deeper into the body and infect other cells. At NanoBio Corporation, a biotech company in Michigan, scientists are perfecting a topical nasal spray that would destroy any single-celled particles, like viruses, bacteria or fungi, on contact, while leaving our multicelled tissues intact. (Blood cells would be fair game for the destructive emulsion, however, so the solution could not be injected into the body.) In animal studies, says Dr. James Baker, the company's chairman of the board, the spray protected 90% of mice from a lethal dose of influenza. The company is also testing a combination of the traditional flu vaccine with the emulsion, which, says Baker, provides a 50-times-greater immune response than the vaccine alone, even if using only one-sixth the usual vaccine dose. This technique is still too experimental to be helpful against the current swine flu outbreak, however.
So far, 10 states have confirmed cases of swine flu, including a death in Texas, but all 50 have already requested their portion of the Strategic National Stockpile (SNS) of antiviral medications, according to the CDC. (The SNS, maintained jointly by the Department of Homeland Security and the Department of Health and Human Services, is the nation's emergency medicine chest, containing critical drugs and medical equipment to be used in a public-health emergency.) Although the stockpiled antiviral drugs can treat existing cases of flu, a vaccine is the only way to protect people who are uninfected and halt further spread of the virus.
The CDC, the only agency that possesses the virus needed to make a vaccine, says it is still "looking very intently" at a swine flu vaccine, but it has not yet given the green light to scale up production. In the event that it does, either in response to the current outbreak or down the road when the next pig-to-people flu causes massive illness, they may have better ways than they did in '76 to battle the bug.