June 26, 2009 – The U.S. is racing to make huge supplies of swine flu vaccine -- and trying to figure out who needs it most -- even as the pandemic sweeps the globe.
Clinical tests will begin within days as researchers struggle to answer basic questions about whether the vaccine works, how big a dose is needed, whether protection will take one shot or two, and whether the vaccine seems safe.
The biggest question -- whether to go ahead and try to vaccinate all 300 million U.S. residents -- won't be answered until the last minute. If the answer is "yes," it will mean a gargantuan effort.
That effort already is well under way, a series of experts reported at this week's meeting of the CDC's Advisory Committee on Vaccination Practices (ACIP).
"It is very clear to us that flu virus can cause serious illness and death. This pandemic virus is no exception," CDC flu chief Nancy J. Cox, PhD, told reporters at the meeting. "It is very clear a vaccine should be developed. If we see a good clear immune response and no safety problems, we will proceed."
The U.S. government already has sunk well over than $1 billion into production of a swine flu vaccine. What has that bought? A lot, says Robin Robinson, PhD, director of BARDA, the Department of Health and Human Services (HHS) branch responsible for ensuring production, procurement, and delivery of biomedical supplies crucial to national preparedness.
If all goes as planned, Robinson says, manufacturers will have 60 million vaccine doses on hand at the end of October, with 100 million more doses by the end of November and 80 million more doses each month thereafter through March 2010.
Mixing the vaccine with an immune-boosting substance called adjuvant would multiply this number of doses, but might delay the start of vaccine production. Manufacturers already are making massive quantities of adjuvant, but these products aren't yet licensed by the FDA; their use would require emergency authorization.
Moreover, flu viruses are tricky -- and so is the making of a flu vaccine. Lots of snags can slow production. And swine flu could become more severe, making it ethically imperative for the U.S. to use adjuvant to stretch vaccine supplies so they can be shared with other nations.
Adding an adjuvant would delay vaccine production to November, Robinson says, although it might be possible to start making regular vaccine and then switching to production of the boosted product.
"Just because we have a lot of vaccine doesn't mean we are going to use it," warned Bruce Gellin, MD, MPH, director of the National Vaccine Program Office and deputy assistant secretary of HHS.
Gellin's point is that making vaccine is one thing, and implementing a huge vaccination program is another. Deciding to make a vaccine requires major decisions:
- Who should get the vaccine first?
- How will the vaccine be delivered?
- How will state and local health departments -- now struggling with huge budget shortfalls and staff reductions -- manage vaccination programs?
- How can vaccine safety be monitored in real time?
Another issue is whether swine flu will wait to strike until people get vaccinated. Since swine flu most frequently attacks school-age children, many experts fear there will be a big wave of cases as schools open in the late summer and early fall.
During the Asian flu pandemic of 1957, Cox says, there was an early wave of flu in September. By the time a vaccine was ready in December, many people had lost interest in vaccination.
That was a big mistake.
"A lot of people died when a new wave came through later that winter," Cox says.