The moment of truth has arrived for the first HIV vaccine to reach Phase III in a decade: this is how ‘Mosaico’ works

Just a few days ago, it was 40 years old of the first official document of what would become one of the pandemics of the 20th century, that of AIDS. That is why it is especially symbolic that, for the first time in a decade, an HIV vaccine goes to Phase III. It’s called ‘Mosaic’ and it’s been developed by Janssen, the Johnson & Johnson affiliate that has developed the coronavirus vaccine. This is what we know.

One of the most sought-after vaccines of the last 40 years

How does the vaccine work? In fact, the technology behind ‘Mosaic’ is very similar to the SARS-CoV-2 vaccine. It is an adenovirus specially modified to carry proteins characteristic of the virus and cause the immune system to generate specific antibodies. Or, more specifically, two (one encoded with three proteins and the other with four).

The idea is to try cover the maximum spectrum of possible mutations (in this case, the different variants of the gag, pol and env proteins of the virus) to try to limit the possibilities of “vaccine escape”. Something that in a virus as elusive as this is really complicated. The last vaccine that reached Phase III had to be kept in a drawer because it only prevented 30% of infections.

Good initial feelings, but the most difficult remains. ‘Mosaico’ has already passed the previous phases demonstrating its safety and efficacy. The studies found antibodies in 97% of those who received the vaccine. But now comes the moment of truth: a trial that will last from 24 to 36 months and will involve almost 4,000 people from all over the world (280 of them in Spain – coordinated by the General University Hospital of Valencia).

An epidemic that became almost invisible. For the western public option. Because, although those five pneumonia Pneumocystis carinii collected by the North American CDC in 1981 were only the beginning of a pandemic that radically changed society at the end of the 20th century and for a long time the idea of ​​”finding the cure for AIDS” became the paradigm of scientific-social objective it is a problem that does not receive all the attention it should.

The arrival of antiretrovirals contained the epidemic in Western countries and, despite being active in continents like Africa with incredible ferocity, progress has been limited. The arrival of the Janssen vaccine in Phase III is, therefore, excellent news.