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Just as the CDC issues a scary warning about the threats of antibiotic-resistant bacteria comes another bit of optimistic medical news in the fight against HIV/AIDS: a vaccine has eradicated the simian immunodeficiency virus (SIV) in infected monkeys.
Researchers have been making encouraging strides in HIV treatment recently—a newborn treated with antiretroviral therapy was “functionally” cured, as were 14 adults who similarly received early treatment for the disease. While these are groundbreaking achievements, they both rely on early diagnosis and treatment—we’re talking a matter of days after the infection started. If one can catch HIV and start treatment that quickly, the odds of survival increase exponentially. A couple months ago, two patients with both HIV and cancer had bone marrow stem cell transplants, a fairly conventional means of treating cancer, but not HIV. The transplant seemed to work double-duty, removing the cancer and, after the course of antiretrovirals, appearing to have functionally cured the HIV.
But early detection and treatment, as well as bone marrow transplants aren’t always possible. The difference with the vaccine developed by Oregon Health & Science University researchers is that it appears to have elicited immune responses that enables the body to purge itself of the virus.
According to their study, the scientists used a strain of SIV called SIVmac239, which develops into AIDS in primates and is far deadlier than HIV. When monkeys contract SIV, they usually die within two years. The vaccine was derived from a cytomegalovirus (CMV), which is related to herpes. The vaccine effectively hitched a ride on the infectious CMV virus, but catalyzed responses in the monkey’s immune systems, rather than infect them.
Researchers vaccinated rhesus monkeys and then infected them with SIV. Initially, the infection took hold and started to do its dirty deed, but then the monkeys’ immune systems started fighting back, destroying the virus. The vaccine was effective in 9 of 16 monkeys. The 9 monkeys that responded to the vaccine were still SIV-free years later. Researchers will soon study whether the vaccine works after the monkeys have already been infected.
The team isn’t sure why the vaccine only worked in just over half of the monkeys—that might simply be due to the virulence of SIV. Still, those are better odds than what we normally associate with HIV treatment. And anyway, those monkeys don’t want to be told the odds.
The next step, of course, is to see if the vaccine could work with humans who have HIV. The treatment would have to undergo scrutiny and testing to assure its safety for human patients, but the team is hopeful that clinical trials for the vaccine could start in as little as two years. Ideally, the vaccine could be used not just to treat already infected patients, but to prevent high-risk patients from ever acquiring the virus.
All this is good news, so let’s not let it be overshadowed by the herpes-infected monkeys that are apparently threatening the health of Floridians. Or maybe scientists have just found their new test subjects. Now we just need to teach these monkeys better manners.