Manufacturers to Begin Work on H1N1 Vaccine

The CDC has taken another step toward developing a vaccine against the novel influenza A (H1N1) virus, but several steps remain before the agency will determine whether to move forward with a national immunization program.

Anne Schuchat, M.D., interim deputy director for the CDC's Science and Public Health Program, said in a May 28 press briefing that the agency has shipped the seed virus to a number of U.S. vaccine manufacturers and plans to send it soon to international manufacturers, as well.

Although Schuchat did not name those manufacturers, vaccine maker Sanofi Pasteur had announced a day earlier that it had received the seed virus and that it planned to begin vaccine development.

Sanofi Pasteur said in a May 27 news release (2-page PDF; About PDFs) that the initial process of getting the virus to grow in a production environment at optimum yield is expected to take about two weeks. The company said that after requisite quality-control measures have been completed, it would be prepared to begin industrial production as soon as directed by public health officials.

On May 25, Sanofi had announced (3-page PDF; About PDFs) that it had accepted the first of what likely would be a series of orders for H1N1 vaccine from HHS. The manufacturer said it expects to commence commercial-scale production in June, and clinical trials could begin as early as August.

"The clinical studies that are going to be done will be vital," Schuchat said during the CDC press briefing.

The studies, which will be conducted based on direction from the FDA and with NIH oversight, will assess whether the vaccine is safe and effective, as well as the number of doses needed to achieve immunity, variations in immune response among different age groups, and whether an adjuvant is required to obtain a satisfactory immune response, Schuchat said.

She added that vaccine manufacturers would use both traditional egg-based methods and newer reverse genetics techniques to develop pilot lots for clinical studies.

Vaccine manufacturer GlaxoSmithKline announced May 22 that it has orders from HHS for H1N1 antigen, as well as adjuvant. The vaccine maker had previously said it had received orders for more than 125 million doses of H1N1 vaccine from four European governments.

The U.S. vaccine production work is moving forward pursuant to a May 22 announcement by HHS Secretary Kathleen Sebelius that her department is directing about $1 billion toward clinical studies on a candidate vaccine and commercial production of vaccine antigen and adjuvant.

In an earlier press briefing, Schuchat had said that it likely would be late summer or early fall before the agency decided whether to recommend a national immunization program against novel H1N1. She reiterated that statement in the May 28 briefing, saying that vaccine probably would not be available outside of clinical trials before October.

As previously reported by AAFP News Now, CDC officials have said that production of seasonal influenza vaccine is nearly complete, and the agency may move up the start of seasonal flu vaccinations, which typically begin in October, to allow time for H1N1 vaccinations.

The World Health Organization's Strategic Advisory Group of Experts on Influenza A (H1N1) Vaccines said in a May 19 report (4-page PDF; About PDFs) that it estimated nearly 5 billion doses could be produced in a 12-month period after initiation of full-scale production if vaccine yield is similar to that obtained for seasonal flu vaccine and dose-sparing formulations are used.

The group also noted that because such factors as optimal antigen content, appropriate dosing regimens, vaccine safety profiles and the interchangeability of H1N1 vaccines from different manufacturers are unknown, postmarketing surveillance would be critical.

The CDC's Advisory Committee on Immunization Practices, or ACIP, is scheduled to discuss the novel H1N1 vaccine during its June 24-26 meeting in Atlanta.

Jonathan Temte, M.D., Ph.D., an associate professor in the department of family medicine at the University of Wisconsin School of Medicine and Public Health, Madison, and a member of the ACIP, said prioritizing who will receive the new vaccine and determining mechanisms for mass immunization will be important issues.

Temte said the novel H1N1 virus' antigenic similarity to the 1976 H1N1 virus needs to be determined as a guide to potential Guillain-Barré syndrome occurrence with use of the vaccine. An estimation of seroprevalence of novel H1N1 in late summer also will be important.

"We will have to know how many people are likely (to be) immune (to) H1N1 due to natural circulation," he said.

In other news, the CDC has updated its interim guidance for submission of tissue samples for testing and the use of face masks and respirators.