A(H1N1) Influenza Vaccine Production Process
(From Sanofi Pasteur)
A novel A(H1N1) influenza virus strain emerged in April 2009, with cases first reported in Mexico and the U.S. Human-to-human spread of the virus soon reached additional countries while world health officials expressed concern for a potential pandemic. As the world’s leading supplier of influenza vaccine, sanofi pasteur immediately activated its pandemic response plan and began assessing its capabilities to support public health efforts and produce a vaccine against the new strain.
The first step in developing (click for graphic)
a vaccine for A(H1N1) is obtaining a seed virus. The seed virus is a specially modified version of the virus designed to produce a vaccine in mass quantities. After world health officials analyze and identify the dominant circulating strain, they select virus strains and submit them to contracted laboratories for preparation of the seed virus. The laboratories will then distribute seed viruses to manufacturers to begin the production process. The seed virus is prepared using either conventional reassortment
or reverse genetics
Pandemic vaccine is manufactured in the same facilities as seasonal vaccine. The decision to start pandemic vaccine production, however, is a complex one that will be made by health authorities in consultation with manufacturers. The key is to balance the availability of both seasonal and pandemic vaccine in order to best meet public health needs.
Upon receipt of the seed virus, sanofi pasteur begins the development process called “passaging,” to prepare a “working seed.” Passaging is the process for acclimating virus to growth in an egg-based production environment at optimum yield. Millions of specially prepared chicken eggs are used to produce the vaccine. The eggs are delivered to sanofi pasteur and each one is injected with the working seed. The eggs are then incubated allowing the virus to multiply. After incubation, the virus-loaded fluid is harvested followed by multiple purification steps to ensure the virus in inactivated.
The FDA will determine the clinical trial protocols for testing all pandemic vaccines. Since people may respond differently to pandemic viruses than interpandemic viruses, it is important to determine safety and dosage prior to implementing a large-scale immunization program.
Quality control tests are performed on all batches for purity, sterility and potency in each step of the production process. Doses of the vaccine are formulated and filled in vials and syringes that must be properly packaged and labeled. Samples of every lot of formulated vaccine are sent to the FDA for release. Shipments of pandemic vaccines begin once health authorities authorize it and establish recommendations for immunization. Click here
for a graphic of A(H1N1) vaccine production.