Aug 14, 2009 (CIDRAP News) – Federal officials today during a pandemic H1N1 planning update dialed back the number of novel flu vaccine doses they expect in October from 120 million to 45 million, listing several reasons for the smaller projection.
During a late July meeting of a federal immunization advisory panel, which targeted 159 million people to receive the first doses, authorities projected that 120 million doses would be available in October, with another 80 million per month in the following months.
However, during a National Biodefense Safety Board (NBSB) teleconference today, Dr. Robin Robinson, director of the Biological Advanced Research and Development Authority (BARDA) at the US Department of Health and Human Services (HHS), said the latest expectation is 45 million doses by mid October, with manufacturers delivering 20 million doses per week after that.
He said the revised estimate is based on several factors expected to slow vaccine delivery from manufacturers. Health officials have already acknowledged that yields of the novel H1N1 antigen are less than for the seasonal flu vaccine. Robinson also said vaccine makers have a limited number of fill-and-finish sites, which are just completing seasonal flu vaccine production, but that federal officials are looking for ways to maximize the current capacity.
CSL Biotherapies, an Australian company that is one of the five manufacturers making pandemic H1N1 vaccine for the US market, has a contractual obligation to produce vaccine first for its home country, Robinson said. Because Australia is in the midst of the Southern Hemisphere's flu season, the United States will work with CSL to ensure that it can deliver vaccine doses to both countries.
Another factor that has added to the delay in ramping up production of the novel flu vaccine is that one of the companies making seasonal flu vaccine is having problems finishing up production so that it can clear the decks to make novel flu vaccine, Robinson said. The delay has impacted vaccine timelines by 4 to 6 weeks, he said.
A new seed strain developed to replace the slower-growing strain in lab studies looks like it will produce better novel H1N1 antigen yields that are on par with those for the seasonal vaccine, Robinson said, adding that federal officials will be working with manufacturers over the next 2 weeks to see if the improved yields are also seen in commercial production.
In an update on the nation's antiviral stockpiles, Robin said that 84 million treatment courses are currently in federal and state stockpiles and that 3 million more doses are expected soon. He projected that a total of 100 million antiviral treatment courses will be available this fall, but he added that only a small amount will be available commercially.
Federal officials are currently discussing if the experimental antiviral drug peramivir should be allowed under an emergency use authorization (EUA) for treating critically ill seasonal or novel flu patients. He said a final decision would be made soon. Peramivir, a neuraminidase inhibitor developed by BioCryst Pharmaceuticals, can be given by intravenous (IV) or intramuscular (IM) routes. Phase 2 study results of the drug were disappointing. However, the company announced in mid July that initial phase 3 study of an IV version of the drug conducted in Asia showed that the drug was safe and well tolerated.
During the comment part of the meeting, some of the NBSB board members and members of the public expressed concerns about the current lack of an IV or IM antiviral treatment, urging officials to strongly consider approving an EUA for peramivir.
Jul 17 BioCryst press release
Jul 29 CIDRAP News story "ACIP targets up to 159 million Americans for H1N1 vaccination"