An HIV vaccine may be 10 years away

Researchers say a cure for the virus that causes the deadly AIDS disease could be on the horizon

Topics: Scientific American, HIV, AIDS Vaccine, Health, stds,

This article was originally published by Scientific American.

Scientific AmericanIf a breakthrough in developing an HIV vaccine occurred today, scientists and drug companies would need another decade to provide a commercial product. But, after a long struggle, researchers may indeed have made that breakthrough using a new vaccine approach that combines two prior ones. Given that the AIDS pandemic has been around for 30 years and has claimed 36 million lives, with 35 million more people currently infected with the HIV virus, the long-awaited goal might finally be attainable, according to researchers attending the 13th Aids Vaccine Conference last week in Barcelona.

This optimism is refreshing because the HIV vaccine track record has not been stellar. Of the five efficacy trials to date, four proved disappointing, with two of them even indicating an increased likelihood of contracting the virus among individuals who were vaccinated. It was only with RV144 (the so-called Thai trial) that a light appeared at the end of the tunnel.

Widely discredited by some heavyweights in the field before the trial results were announced, the RV144 vaccine showed the efficacy of an approach called prime boost—combining a DNA vaccine with a protein vaccine. RV144 provided 31 percent more protection than a placebo. The modest success was enough to spark the creation of the Pox Protein Public–Private Partnership (P5), a consortium of governments, companies and nongovernmental organizations that plans to take RV144 all the way to licensed product.

Despite the optimism about RV144, other researchers still question whether governments should be investing in a vaccine instead of concentrating on prevention and treatment strategies. Yes they should, said Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases, during a plenary speech. “An HIV vaccine is essential to durably control and effectively end the pandemic,” Fauci asserted.

Of antibodies and T cells
Researchers follow two main approaches to an HIV vaccine: antibodies and T cells. Antibodies, proteins produced by the immune system to identify and neutralize foreign objects, were big in the early years of the research, but after disappointing results interest moved to responses conducted by immune cells. This changed again with the discovery of broadly neutralizing antibodies, which are produced by 20 percent of HIV-positive individuals two or three years after infection.

These antibodies are able to target specific regions of the virus that are important for its survival and are present in many of the different HIV subtypes. So a vaccine comprising them might be effective despite the virus’s variability, a problem that has been a considerable hurdle. They are so promising, researchers at the meeting said, that one of the recommended therapeutic approaches is to inject the antibodies directly into the bloodstreams of those at risk. Although these antibodies have been used to treat specific illnesses, they have not been considered as a vaccine substitute for the broad population.

You Might Also Like

Another strategy is to use the parts of the HIV virus these antibodies recognize as models to teach the immune system how to make more of their own broadly neutralizing antibodies. But neutralization is not the only ability these molecules bring to the fight. The RV144 trial showed that antibodies can also battle the virus tapping other abilities that, for example, lead to the death of the infected cell.

Despite these novel investigations, researchers at the conference noted that work to exploit the body’s own T cells—immune cells that can promote a response or kill an infected cell—has not been forgotten. Although vaccines based on them have thus far failed to prevent infection, they still prove somewhat effective in therapeutic applications directed at controlling viral load in those already infected. In fact, the combination of antibody and T cell approaches is one of the avenues the researchers are beginning to explore—the holy grail being a vaccine that can prevent infection as well as control virus replication.

The way forward
As that work proceeds, experts are anticipating more results from follow-up studies of RV144 that should determine the effects of additional booster shots. One of the studies, RV305, showed that patients from the original RV144 trial displayed a spike in immune response with a boost six or eight years after being vaccinated. The P5 consortium is also planning to use the same vaccine structure from RV144 in South Africa, adapted to the HIV subtype common there.

The future will probably also see much greater cooperation among the various camps within the field: vaccinologists and pathogenicists, preventive and therapeutic vaccines, vaccine and microbicide approaches. As a matter of fact, the Barcelona meeting was the last Aids Vaccine Conference. Next year the gathering will be called the HIV Research for Prevention Conference (H4P) and will bring together the fields of vaccines, microbicides and antiretroviral drugs.

The new crossover of work and communication can only help in finding an effective vaccine, said Jose Esparza, senior advisor on global health of the Bill & Melinda Gates Foundation, during a closing plenary. It will generate even more human data, which trumps everything that is done in vitro, he said. “Different vaccine concepts need to be tested in parallel. Clinical trials are critical, especially large-scale ones,” Esparza declared. “We need to conduct our research with the necessary sense of urgency that the epidemic is imposing on us.”

More Related Stories

Featured Slide Shows

  • Share on Twitter
  • Share on Facebook
  • 1 of 13
  • Close
  • Fullscreen
  • Thumbnails

    The 12 most incredible pint-size look-alikes in "Orange Is the New Black" season 3

    DAYA  
    Young Daya has yet to become entirely jaded, but she has the character's trademark skeptical pout down pat. And with a piece-of-work mother like Aleida -- who oscillates between jealousy and scorn for her creatively gifted daughter, chucking out the artwork she brings home from summer camp -- who can blame her?

    The 12 most incredible pint-size look-alikes in "Orange Is the New Black" season 3

    MORELLO   
    With her marriage to prison penpal Vince Muccio, Lorna finally got to wear the white veil she has fantasized about since childhood (even if it was made of toilet paper).

    The 12 most incredible pint-size look-alikes in "Orange Is the New Black" season 3

    CINDY   
    Cindy's embrace of Judaism makes sense when we see her childhood, lived under the fist of a terrifying father who preached a fire-and-brimstone version of Christianity. As she put it: "I was raised in a church where I was told to believe and pray. And if I was bad, I’d go to hell."

    The 12 most incredible pint-size look-alikes in "Orange Is the New Black" season 3

    CAPUTO   
    Joey Caputo has always tried to be a good guy, whether it's offering to fight a disabled wrestler at a high school wrestling event or giving up his musical ambitions to raise another man's child. But trying to be a nice guy never exactly worked out for him -- which might explain why he decides to take the selfish route in the Season 3 finale.

    The 12 most incredible pint-size look-alikes in "Orange Is the New Black" season 3

    BOO   
    In one of the season's more moving flashbacks, we see a young Boo -- who rejected the traditional trappings of femininity from a young age -- clashing with her mother over what to wear. Later, she makes the decision not to visit her mother on her deathbed if it means pretending to be something she's not. As she puts it, "I refuse to be invisible, Daddy. Not for you, not for Mom, not for anybody.”

    The 12 most incredible pint-size look-alikes in "Orange Is the New Black" season 3

    SOSO
    We still don't know what landed Brooke Soso in the slammer, but a late-season flashback suggests that some seriously overbearing parenting may have been the impetus for her downward spiral.

    The 12 most incredible pint-size look-alikes in "Orange Is the New Black" season 3

    POUSSEY
    We already know a little about Poussey's relationship with her military father, but this season we saw a softer side of the spunky fan-favorite, who still pines for the loving mom that she lost too young.

    The 12 most incredible pint-size look-alikes in "Orange Is the New Black" season 3

    PENNSATUCKY
    Pennsatucky had something of a redemption arc this season, and glimpses of her childhood only serve to increase viewer sympathy for the character, whose mother forced her to chug Mountain Dew outside the Social Security Administration office and stripped her of her sexual agency before she was even old enough to comprehend it.

    The 12 most incredible pint-size look-alikes in "Orange Is the New Black" season 3

    CHANG
    This season, we got an intense look at the teenage life of one of Litchfield's most isolated and underexplored inmates. Rebuffed and scorned by her suitor at an arranged marriage, the young Chinese immigrant stored up a grudge, and ultimately exacted a merciless revenge.

    The 12 most incredible pint-size look-alikes in "Orange Is the New Black" season 3

    HEALY
    It's difficult to sympathize with the racist, misogynist CO Sam Healy, but the snippets we get of his childhood -- raised by a mentally ill mother, vomited on by a homeless man he mistakes for Jesus when he runs to the church for help -- certainly help us understand him better.

    The 12 most incredible pint-size look-alikes in "Orange Is the New Black" season 3

    NORMA
    This season, we learned a lot about one of Litchfield's biggest enigmas, as we saw the roots of Norma's silence (a childhood stutter) and the reason for her incarceration (killing the oppressive cult leader she followed for decades).

    The 12 most incredible pint-size look-alikes in "Orange Is the New Black" season 3

    NICKI
    While Nicki's mother certainly isn't entirely to blame for her daughter's struggles with addiction, an early childhood flashback -- of an adorable young Nicki being rebuffed on Mother's Day -- certainly helps us understand the roots of Nicki's scarred psyche.

  • Recent Slide Shows

Comments

Loading Comments...