30 March 2006
Bird Flu Vaccine Would Require Supplies Beyond Capacity
After clinical trial, U.S. researchers search for further solutions
Washington -- A trial vaccine against the H5N1 strain of avian influenza produced some immune response in a study conducted on 450 healthy adults, but unusually high levels of the vaccine were required, according to results published in the New England Journal of Medicine (NEJM) March 30.
An accompanying editorial says worldwide vaccine production capacity would be inadequate to make enough vaccine to protect the large populations that could be vulnerable if pandemic influenza begins to sweep the world.
The level of vaccine required to produce an immune response in trial subjects was 12 times that used in normal annual influenza immunization campaigns.
Projecting the results of the trial across the world, editorialist Dr. Gregory Poland writes that the world’s vaccine supply would be sufficient to provide dosages for only 75 million people – 1.25 percent of the world’s population.
The trial also showed that the vaccine produced a lower-than-hoped-for level of immunity. Poland calculated that, of the 75 million who received vaccine doses, only half would achieve a reliable level of protection.
The National Institute of Allergy and Infectious Diseases (NIAID), one of the U.S. National Institutes of Health, backed the study conducted at three university-based NIAID-supported Vaccine and Treatment Evaluation Units.
In a press release, NIAID Director Anthony Fauci said researchers are working to address the challenges in the development of a vaccine against the H5N1 virus.
“We are investigating other options,” he said, “that may allow us to reduce the dosage – for example, adding an immune booster, or adjuvant, to the vaccine –so we can achieve a more practical immunization strategy.”
NIAID announced the preliminary results of the trial in August 2005, and publication of the results in NEJM marks completion of analysis of the trial findings.
In his editorial, Poland writes that the development of alternatives is “imperative both to improve immunogenicity [its capability to promote an immune response] and to increase the number of doses available.”
Poland is involved in a trial of a flu vaccine being conducted by Merck Research Laboratories. His essay echoes observations made by a number of U.S. officials over the last several months, as concerns about pandemic influenza have increased.
Vaccine production methods are slow and outdated, and already have led to U.S. supply problems in the routine preparation and distribution of serums for each annual flu season.
Pandemic influenza resulting from a highly virulent strain would produce a staggering level of illness that would make the annual flu season seem tame in comparison.
The annual flu results in about 36,000 deaths and more than 200,000 hospitalizations each year in the United States alone.
An estimate compiled by the Congressional Budget Office predicts that pandemic influenza could cause as many as 90 million critically ill and 2 million dead in the United States, with vastly higher numbers worldwide.
The National Strategy for Pandemic Influenza, released by the Bush administration in late 2005, calls for “significant and targeted investments in promising technologies” to produce “next-generation countermeasures against influenza.” (See related article.)
A form of bird flu that began in Southeast Asia more than two years ago has spread to dozens of countries and caused the deaths of tens of millions of birds from disease or through culling ordered to prevent the further spread of sickness through flocks of domesticated birds.
The disease has infected almost 200 humans, resulting in 105 deaths. Those cases most often have resulted from direct contact with diseased animals.
If the H5N1 virus mutates to become contagious among humans, widespread illness and death would occur because humans do not have immunity to this strain.
The NIAID press release is available on the institute’s Web site. The National Strategy for Pandemic Influenza is available on the White House Web site.
For ongoing coverage of bird flu and pandemic influenza, see Bird Flu (Avian Influenza).
(Distributed by the Bureau of International Information Programs, U.S. Department of State. Web site: http://usinfo.state.gov)
|
NEWSLETTER
|
| Join the GlobalSecurity.org mailing list |
|
|
|
