By Bob Roehr
WASHINGTON – The worldwide forecast for HIV/AIDS continues to be grim, with intermittent reasons for hope, according to an update on the epidemic released by UNAIDS and the World Health Organization.
The estimate of the total number of people living with HIV has topped 40 million, which appears to be a leveling off of the rate of increase. Most troubling is that new infections are estimated to be about five million a year. Thus a slowing in the rate of total infections in large part reflects the reality that more people are dying of AIDS.
Estimates for the United States are that more than a million people are living with the virus, while 40,000 become infected and 18,000 die each year. Financial resources, already inadequate, are not keeping pace with the growing caseload.
While UNAIDS has fallen short of its ambitious “3 X 5” goal of getting three million people in the developing world into treatment by the end of 2005, it has made substantial progress toward that goal and is likely to achieve it some time next year.
But creating the health care infrastructure necessary to deliver HIV therapy to all of those who need it is a daunting task that will continue to grow, unless the number of new infections is slowed dramatically.
UNAIDS director Peter Piot said that new infections are declining in a few sub-Saharan African countries and in the Caribbean, largely because HIV prevention efforts are working.
However, “HIV stigma and the resulting actual or feared discrimination have proven to be perhaps the most difficult obstacles to effective HIV prevention,” according to the report. This has created “an ideal climate” for the perpetuation and spread of the epidemic.
Another kink in prevention is that religious moralists have successfully shifted U.S. support for prevention activities from a balanced approach that included condoms to one that stresses abstinence only.
The so called “global gag rule” prohibits U.S. government funding of any organization that provides abortion counseling or services as part of comprehensive family planning. Other provisions deny funding to organizations that do not condemn sex work. That provision is being challenged in federal court in a hearing that has been rescheduled for Dec. 20.
A preventive vaccine has been an important part of controlling every other infectious disease in the past. The search for an HIV vaccine is in its second decade but unlike with other infectious diseases, there is no model of recovery upon which to build.
The problem is compounded by the genetic instability and variability of the virus. “There are literally millions of HIV sequences in the world,” said Gary Nabel in a recent presentation. He is director of the Vaccine Research Center at NIH.
HIV also is “a moving target biochemically” in that its structure changes as it binds to and enters a cell “and the immune system doesn’t really have a chance to see the structures that you want to generate antibodies to.”
Nabel said they have developed a prime/boost strategy using DNA plasmids of HIV that look good in terms of generating antibodies in humans. They hope to move the vaccine into a proof of concept trial next year.
What they will be looking for is only the starting point that Jonas Salk and others used to develop their successful vaccine against polio. He said, “We would like to see immunologic protection in a subset of individuals, and then identify both immune and genetic correlates of protection.”
They will build upon that with second and third generation vaccines that might generate protection that is stronger and occurs in more people. The one thing that is assured is that the journey will continue to be long and hard.