July 24, 2009 — Vaccine makers told an FDA panel of experts that they're moving ahead with rushed plans to produce a swine flu vaccine and could have doses ready to distribute to the public by mid-October.
Federal officials are planning a massive fall vaccination campaign against H1N1, the virus that causes swine flu and has caused thousands of hospitalizations and more than 170 deaths since the spring.
The government has devoted billions of dollars to private companies as part of an emergency vaccine production program.
Companies and government officials are rushing to test and produce a swine flu vaccine in time for an expected resurgence of the H1N1 virus in the fall. The effort is potentially complicated by the fact that manufacturers must also continue making a separate vaccine against the seasonal flu, which kills an estimated 36,000 people per year in the U.S.
"Time is really not on our side," FDA official Wellington Sun, MD, said.
Company officials told the FDA panel Thursday that they would probably be able to produce enough vaccine to protect 50 million people by mid-October. That's an uncertain estimate, the companies said.
Up to 100 million doses could be produced by that time, but it's unclear whether it will take one dose or two to generate immunity against H1N1 in most patients.
At the same time, companies warned that the process of growing H1N1 viruses for use in a vaccine has shown lower than usual yields, suggesting vaccine production could go more slowly. Some gave a "worst case scenario" that H1N1 vaccine production may not peak until December or later.
Monitoring for Potential Changes in H1N1 Virus
Scientists are also closely watching H1N1 as it circulates through the flu season in the Southern Hemisphere. Flu vaccines are notorious for rapid genetic shifts that can help them evade vaccines. That's a wild card in vaccine development.
Nancy Cox, MD, PhD, director of the influenza division at the CDC, said H1N1 has so far shown reassuring stability.
"We're continuing to monitor very carefully but we haven't actually seen anything we believe is significant" in terms of increasing virulence, Cox told the panel.
Children and adolescents appear more vulnerable to H1N1 infection than adults. Federal officials earlier this month suggested they will mount a large-scale vaccination campaign in U.S. schools provided that adequate vaccine supplies become available in the fall.
In mid-July, the National Biodefense Safety Board (NBSB) -- a board of advisors to the Health and Human Services Department -- recommended that swine flu vaccine should be fast-tracked. The NBSB recommended vaccinations should begin in mid-September -- soon after schools open.
The Advisory Committee on Immunizations Practices (ACIP) is set to meet next week to decide which groups should be first in line to receive vaccines. That list will likely include children, but could also include health care workers, pregnant women, and adults with chronic diseases.
Five manufacturers are licensed to make influenza vaccines in the U.S. All five are ramping up efforts to produce and test H1N1 vaccine.
Companies change the virus strains that go into the regular flu vaccine for each flu season. Companies are typically not required to submit brand-new safety and effectiveness data for each new vaccine. FDA officials said they are allowing companies to test the separate H1N1 vaccine under the same rules.
But that could mean that the pandemic vaccine gains an FDA license and hits the market before full safety data is available, though officials stressed that the process is typical of new vaccine licenses for each new flu season.
"If an immunization program is recommended, we may not, depending on the situation, may not have all that information," said Jesse Goodman, MD, FDA's acting chief scientist.
SOURCES:
Wellington Sun, MD, FDA.
Jesse Goodman, MD, acting chief scientist, FDA.
Nancy Cox, MD, PhD, director, influenza division, CDC.
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