Experimental HIV Vaccines Likely Will Offer Limited Immunity, Might Delay Onset of AIDS, Commentary Says

Many of the most promising experimental HIV vaccines in development will offer only limited immunity against the virus but might delay the onset of AIDS, Anthony Fauci, director of NIH's National Institute of Allergy and Infectious Diseases, and Margaret Johnston of NIAID write in a New England Journal of Medicine commentary, AFP/Yahoo! News reports. The commentary was published ahead of HIV Vaccine Awareness Day, which is May 18.

Although the first generation of HIV vaccines likely will not prevent HIV infection, they might protect HIV-positive people's immune systems from the "worst ravages" of the disease and delay the onset of AIDS, according to AFP/Yahoo! News. The vaccines also are potential tools for public health authorities trying to contain the HIV/AIDS pandemic because vaccines can potentially reduce viral loads in HIV-positive people, therefore reducing their ability to transmit the virus to others (Daly, AFP/Yahoo! News, 5/16).

According to studies of HIV in humans and animal models, experimental vaccines that induce strong responses from CD4+ T cells "in the absence of broadly neutralizing antibodies may prove beneficial even if infection is not completely prevented," Fauci and Johnston write. They add that the vaccines might "prevent the early and massive destruction of memory CD4+ T cells that help control infection and prolong disease-free survival." In addition, "secondary transmission may also be reduced if the vaccine helps to control viral replication," the authors write (Johnston/Fauci, NEJM, 5/17).

According to Fauci and Johnston, some animal studies indicate peak viral loads were reduced by a factor of 10 in primates that were inoculated with these types of vaccines and then infected with the simian counterpart of HIV. The inoculations also "dramatically" slowed the progression of the disease in many animals, the authors write. They add that although it is not clear when the first vaccines will be available, Phase I and II clinical trials are "well into their execution" and large "numbers of people are being vaccinated." While these new vaccines likely will offer only limited immunity, there is "optimism that even a less-than-perfect vaccine could benefit both individual recipients and the at-risk community," Fauci and Johnston write (AFP/Yahoo! News, 5/16).

The commentary is available online.

The San Francisco Chronicle on Friday also ran an opinion piece by Fauci and Johnston on experimental HIV vaccines. The opinion piece is available online.

Newspapers Respond to HIV Vaccine Awareness Day
Two newspapers recently published opinion pieces to mark HIV Vaccine Awareness Day. Summaries appear below.

• Patricia Thomas, Atlanta Journal-Constitution: Former President Clinton 10 years ago "challenged America to develop a vaccine to prevent AIDS within the next decade," and "thousands of people will come together" on HIV Vaccine Awareness Day to "see how far we've progressed toward a vaccine that is effective and safe," Thomas -- Knight Chair in Health and Medical Journalism at the University of Georgia's Grady College of Journalism and Mass Communication -- writes in a Journal-Constitution opinion piece. According to Thomas, "Only a preventive vaccine can halt the spread of AIDS, and only large clinical trials can determine which of the candidates in the pipeline will work" (Thomas, Atlanta Journal-Constitution, 5/18).
  
  
• Omu Anzala and Walter Jaoko, Kenya's Nation: HIV Vaccine Awareness Day is a "day to renew our commitment to the discovery of technologies to halt HIV/AIDS" and "is an appropriate time for us to rededicate ourselves to the cause" of ending AIDS, Anzala and Jaoko, both of the University of Nairobi's Department of Medical Microbiology, write in a Nation opinion piece. "Although an effective, accessible AIDS vaccine continues to elude us, we can be proud of the leadership role Kenya has played in supporting AIDS vaccine research and development," Anzala and Jaoko write. "The search for an AIDS vaccine is a long and difficult process that requires time and single-minded persistence," the authors write, adding that it also requires "[l]ong-term political support and commitment, financing, education and global cooperation" (Anzala/Jaoko, Nation, 5/17).