November 2, 2009
Meeting The Challenge Of H1N1 Vaccine Production
By Michael D. Shaw
Frustration seems to be the byword. After months of hype, and even hysteria over the H1N1 flu, frustration reigns as many people who want to get vaccinated are unable to find a clinic that has the vaccine. Those expressing concern include Thomas R. Frieden, MD, MPH, director of the CDC: “We are now in a period where the vaccine’s availability is increasing steadily, but far too slowly. It’s frustrating to all of us. We wish there was more vaccine available.”
As it is, this effort is the most ambitious vaccination program our country has undertaken since the anti-polio campaign of the 1950s. The vaccine manufacturers are working hard to meet the demand, but this year’s situation presents some additional challenges.
- Two flu vaccines are needed—one for the seasonal flu, and one for the H1N1 variety
- The H1N1 vaccine is being offered as a nasal spray, in thimerosal-free single-dose syringes, and in multi-dose vials
- Since the H1N1 vaccine is new, the FDA required additional testing before granting approval
No doubt, the voices of anti-vaccination activists, some of whom have absolutely no background in health care, and others who are not aware of the plain facts, served to gum up the works, as well. For example, vaccine opponents have expressed concerns about the safety of adjuvants—ingredients used to boost the immune response a vaccine generates. While adjuvants will be used in many H1N1 shots outside the U.S., they aren’t being used in the U.S. vaccine. In any case, manufacturers and health officials note that adjuvants have been studied extensively and are safe.
Not surprisingly, there have been plenty of complaints about the 50-year-old technology used in vaccine production.
Traditionally, influenza vaccines are produced in fertilized chicken eggs. Eleven days after fertilization, the influenza virus is injected into the eggs and accumulates in the fluid surrounding the embryo. The embryo becomes infected so that the virus can multiply. After several days of incubation, machines open the eggs and harvest the virus. The virus is then carefully purified, chemically inactivated and used to produce the vaccine. Typically, between one and two eggs are needed to produce one dose of vaccine. The entire production process takes at least six months.
Unfortunately, yields in the initial H1N1 production seed strain provided by the World Health Organization were far below normal. Vaccine makers reported yields 50 to 75 percent less than that of the typical seasonal flu shot. The low yields slowed production, but have increased dramatically since July, and the advent of a new seed strain. To be sure, vast quantities of chicken eggs are required for this process, and more than 30 farms in the eastern United States are under long-term contracts to provide eggs for vaccine production.
Responding to calls for improving the process, the government has invested in novel technology for vaccine production.
Novartis has received a $487 million contract to run a plant in North Carolina that will make flu vaccine by growing the virus inside animal cells, preferably from mammals. The plant is expected to be up and running by 2011 or 2012. Another interesting approach is being used by Protein Sciences Corporation, awardee of a five-year, $147 million contract to develop a vaccine using its recombinant technology—flu proteins grown in insect cells. It is thought that this method can produce vaccine within 12 weeks, a big improvement over current methods.
“I think you’re going to see these new technologies come on board rapidly, especially given what’s happened this year,” said Paul Radspinner, president and chief executive of FluGen Inc., a company working on several new vaccine technologies.
Still, the tried and true chicken egg method is what we have now, so patience and understanding, rather than political gamesmanship is what is needed. According to Dr. Nicole Lurie, assistant health and human services secretary for preparedness, the government now hopes to have about 50 million doses out by mid-November and 150 million in December. “By the end of November, I think we’re going to be pretty well back on track,” she said.
Until that time, though, prudence and good policy demand that certain groups be vaccinated first. This would include…
- Pregnant women
- People who live with or care for children younger than 6 months of age
- Health care and emergency medical services personnel
- Persons between the ages of 6 months through 24 years of age
- People from ages 25 through 64 years who are at higher risk for novel H1N1 because of chronic health disorders or compromised immune systems
Check with your health care provider for updates on availability of the H1N1 vaccine.