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Novel H1N1 vaccine doses may be limited.

Manufacturing issues may limit the number of vaccine doses against novel influenza A(H1N1) that will be available when immunization programs begin around mid-October, officials from the Department of Health and Human Services told members of the National Biodefense Science Board in a public teleconference.

But clinical trial testing of the inactivated and live attenuated virus vaccines already is underway, and programs for distributing the vaccines and conducting surveillance should be in place when the vaccines are ready, the officials said.

Robin Robinson, Ph.D., director of the Biomedical Advanced Research and Development Authority of HHS, reported that, for the most part, vaccine production and testing are on schedule. All five vaccine manufacturers recently received their potency assay reagents so they can know how much vaccine they have produced. But an unanticipated difficulty in bulk production of the live attenuated virus vaccine has slowed its progress.

Although vaccination programs still are slated for mid-October, the number of doses that will be available by then has been lowered from 120 million to 45 million, with 20 million doses coming out each week afterward, Dr. Robinson said. The reduction in doses is a result of lower than expected vaccine yield, compared with previous yields with seasonal flu vaccines. One manufacturer also had obligations to produce vaccine for Australia ahead of other clients. Another manufacturer's difficulty in finishing up its orders of seasonal influenza vaccine has affected the time line for novel H1N1 vaccine production.

The federal government already has bought 190 million vaccine doses and, if needed, 120 million adjuvant doses. It also has stockpiled 84 million treatment courses of antivirals and another 3 million are expected to arrive soon. In May, states were able to purchase 11 million antiviral treatment courses; another 2 million have been recently purchased, Dr. Robinson said.

The government plans to distribute the vaccine in a manner similar to the Vaccines for Children Program, based on orders from state and territorial health departments that will be sent to a central distributor to fill and then go to health care providers, retail pharmacies, or state or local public health facilities. Ancillary supplies should arrive before or at the same time as the vaccines, said Dr. jay Butler, program director of the Centers for Disease Control and Prevention's H1N1 Vaccine Task Force.

The CDC will track the total number of doses administered to provide a rough estimate of the number of vaccinated people and if the doses have been given to specific age groups recommended by the Advisory Committee on Immunization Practices.

The National Immunization Survey will be set to begin collecting immunization data as early as Oct. 10 for weekly reports of national coverage estimates. While clinical trials will provide data on reactogenicity to the vaccine, rare adverse events will be monitored through the Vaccine Adverse Event Reporting System and the population-based Vaccine Safety Datalink.

Vaccine safety in the military will be collected though the Defense Medical Surveillance System, a collaboration between the Department of Defense and the Food and Drug Administration. A special surveillance program also will be set up for Guillain-Barre syndrome, Dr. Butler said.

Dr. Daniel B. Jernigan, deputy director of the CDC's National Center for Immunization and Respiratory Diseases, noted that public health laboratories will focus their testing more on surveillance than clinical testing capacity.

The CDC also is no longer posting counts of laboratory-confirmed cases of novel H1N1 virus on its Web site, but it is still working with state health departments to collect and report the number of laboratory-confirmed hospitalizations and deaths in the United States, Dr. Jernigan said.

Since the week of Aug. 2, the numbers of laboratory-confirmed hospitalizations for novel H1N1 virus have climbed from about 6,500 to 7,511 and deaths from 436 to 477. However, the overall trend in these numbers is not rising as fast as it had in the past, he said.

The percentage of outpatients presenting with influenzalike illness at clinics--out of the total number of people seen at clinics--is below the national baseline, Dr. Jernigan said, but nonetheless the percentage is still higher than what is seen normally at this time of year. The states in which this percentage has increased the most are Florida and North Carolina.

Only four states are currently reporting widespread cases of novel H1N1 virus infection; most are reporting only sporadic or local activity.

The proportion of the numbers of deaths attributed to pneumonia and influenza have been "low and are about what you'd expect for summer," Dr. Jernigan said.

Nearly 100% of the influenza specimens that have been characterized by CDC and state public health labs are novel H1N1 virus, he said. No significant antigenic drift of novel H1N1 virus away from what is in the vaccine has been encountered so far in the United States, he said.
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Author:Evans, Jeff
Publication:OB GYN News
Date:Sep 1, 2009
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