For the first time in more than 10 years, a prototype HIV vaccine has reached the last phase of the trials, the 3, which must determine whether in the real world it is capable of protecting against the transmission of the virus that, if left untreated, causes AIDS. The drug has been developed by Janssen, and uses the same technology that the pharmaceutical company has used in your covid vaccine: an adenovirus modified so that it transports the DNA of its most representative proteins into the cells of the subject so that the individual’s body creates antibodies against them. In truth, they are two vaccines (one encoded with three proteins and another with four, which because they have this mixture are called mosaic), says Antonio Fernández, a researcher at the pharmaceutical company. Both have passed safety studies and have been seen to create antibodies, as this article attests to. The Lancet, but it remains to be seen if they work in real conditions. The trial will last from 24 to 36 months, says Fernández, to verify the permanence and intensity of the protection. The previous attempt to get an HIV vaccine it ended in 2009 when it was found to prevent only 30% of infections.
José Moltó, of the Foundation for the Fight against AIDS, is one of the doctors who will participate in the trial, which has begun to recruit volunteers (there will be 250 out of 3,800 in Spain). Moltó explains that the delay in getting this vaccine is due to the fact that HIV has “tremendous variability.” “Being pressed [por las células del sistema inmune] it changes its external appearance and escapes ”. What this drug does is that it targets different variants of the gag, pol and env proteins of the virus, which makes it more difficult for it to evade the action of the antibodies created. It is, at another level, similar to what happened 25 years ago with antiviral treatments: they began to be effective when several were combined that interrupted the replication cycle of the virus at different points.
Indeed, the success of these treatments is one of the causes that has led to less talk about HIV and AIDS, despite their prevalence. The National AIDS Plan calculates that last year there were more than 2,600 newly infected, in line with a slightly downward trend from 3,000 or 3,500 a decade ago. 85.8% were men and the median age (the central value of the ages of all the infected placed in order) was 36 years, but even so, according to the National Institute of Statistics (INE), with a mortality of more than 400 people per year. The result is that some 150,000 people with HIV live in Spain, according to the latest estimate by the Spanish Group for the Study of AIDS (Gesida), a number that is increasing slightly each year.
This gradual reduction in transmissions has meant that for the test men or trans people are sought as volunteers who have sex with men, explains Moltó, since it is the population group where the incidence is higher (they represent more than half of the new infections in Spain, according to data from the national plan). In another branch of the study, in South Africa, on the other hand, 1,500 women are going to be tested, since there the transmission is mainly through heterosexual sex. This trial, called Invocodo, is a phase 2 (it measures safety and the generation of antibodies), but given the profile of the participants, it will also be seen if there is a real protective effect of the vaccine, says the representative of Janssen. And it is that the African continent represents more than 40% of new HIV infections in the world, which are about 1.7 million and the same percentage of deaths (690,000 on the planet in 2019). Despite being discovered 25 years ago, UNAIDS still estimates that 12 of the 38 million people in the world living with the virus they do not receive treatment. They are the ones who over time may develop AIDS, the set of diseases caused by infectious agents that a person with an undamaged immune system rejects without knowing it.
The success of current treatments makes one pill a day keep the virus in check and reduce it so much that the infected person cannot transmit it to another (which is reflected in the motto undetectable = untransmittable)But its success has slowed recent research for a vaccine, says Esteban Martínez, president of Gesida. Already in 2009, the attempt that went the furthest was rejected after achieving 30% protection. Now, “the standard with which it is compared is very high,” says Martínez. “20 years ago, the urgency was greater,” says Martínez, because there were no other alternatives like now, in which antiviral therapy for those who already have the virus and the so-called pre-exposure prophylaxis (Prep), a pill that protects against HIV if taken before unprotected sex, they have achieved good control of the disease at a reasonable cost, since in many cases there are generics of the preparations, says the president of Gesida, who sees in the development of a vaccine a series of obstacles – its cost, that its protection is not very durable, that the response is not very intense, the need to revaccinate – which makes him say that although he would like there to be one, he sees it as very difficult and believes that prevention can be achieved by other means.
Ramón Espacio, President of the State Coordinator for HIV and AIDS (Cesida), believes, however, that the doctor’s objections are justified in rich countries, but that “everything will depend on the efficacy and regimen” of the vaccine. If it can work with one or two punctures for life or every five years, “it will be more comfortable and more applicable to the population of poor countries.” This is what Fernández, from the manufacturing laboratory, argues. “You can get a lower cost than the treatments and it can be easier to administer than relying on people in places where even drinking water is lacking to take a daily pill.”
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