May 31, 2023

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RV144: The largest HIV vaccine trial in history

RV144: The largest HIV vaccine trial in history


RV144: The largest HIV vaccine trial in history.  In less than a year, scientists have developed several vaccines against COVID-19. But when we cheer for joy, we still live in the shadow of another pandemic. The search for a vaccine against HIV (the virus that causes AIDS) has been going on for nearly forty years.

So far, only one large-scale trial has proved its effect in preventing viral infections is even negligible: Thailand’s RV144 trial is the largest HIV vaccine trial in history.

Powel Kazanjian, an infectious disease expert, wrote that after the discovery of HIV in 1983, some scientists hope to launch a vaccine against AIDS within two years. Unfortunately, the traditional methods of developing vaccines are not suitable for HIV. The virus mutated too quickly.

RV144 lasted for three years, from 2003 to 2006, it is the fourth HIV vaccine efficacy test completed so far. Kazanjian wrote that this is also one of the first coordinated methods to test vaccine treatments. The Phase III clinical trial recruited 16,000 volunteers in Thailand to test the broad efficacy of two vaccine combinations (one “normal” and one “enhanced”). It is mainly funded by the US government and recognized by 11 international review agencies.

Some people think that this kind of cooperation is not enough: the National Institutes of Health has not solicited enough independent scientists, nor has it established a transparent process to decide which treatments to move forward. Moreover, neither vaccine was independently successful (hence the introduction of a novel “boost injection” concept).

Several groups of scientists expressed their concerns in a letter to “Science” magazine: “We believe that greater selectivity is needed to ensure that products that meet the Phase III efficacy test are promising products with a reasonable chance of success.” Robert Gallo, a co-discoverer of HIV, expressed his concern in another letter, “The high cost of phase III clinical trials can easily make the field of resources scarce and unable to promote the development of these drug candidates.”

Some scientists disagree: In the same issue of Science, Robert Belshe and others. He wrote: “If this trial increases the knowledge about AIDS vaccine development and can even prevent some HIV/AIDS cases in the future, its contribution will be very important.”

In 2009, three years after the trial was completed, the results were published. They found that the HIV infection rate has decreased slightly, and the reported effective rate is about 32%. This is not an encouraging statistic. The treatment requires at least 50% of the efficacy to support approval. This is the first evidence that any type of HIV vaccine is effective. During the study, a total of 160 volunteers died, none of which had symptoms directly related to the treatment.

Ten years later, Mitchell Warren, executive director of the AIDS Vaccine Advocacy Alliance, reviewed the results of the RV144 trial and believed that it “redirected the collective search for AIDS vaccines”, which triggered “unbelievable Proof-of-concept cascade”. He called RV144 a catalyst, a revival in the field. Recently, a new HIV treatment method has shown promise in the early “proof of concept” stage, and may be combined with RNA technology for further innovation. The fight against HIV is far from over, but scientists have not given up because of it.


(source:internet, reference only)

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