If only virologists had a penny for every time they were asked why a Covid-19 vaccine was produced so quickly, but we still don’t. HIV vaccine, unreliable contracts and bureaucratic races to find financing for them will end. It’s true that it’s shocking, but a vaccine against the virus that causes AIDS is one of science’s greatest challenges for many reasons. For this reason, the results obtained by a group of scientists from Duke Human Vaccine Institute They are the most interesting.
In phase 1 clinical trials, they were able to produce in humans what is known as broadly neutralizing antibodies. These are antibodies that can attack a wide range of viral strains. Its existence in relation to HIV has been known since the 1990s, but until now a vaccine has been unable to stimulate its production.
They were observed only in natural infections. The problem is that even in these cases they are difficult to generate. It is assumed that only one 10%-25% of patients They manage to develop them and invest more than two years in it. What’s going on with HIV? Why is it so elusive to our immune system? Before you can start running, you need to learn to walk. So these scientists spent a lot of time answering these questions, and once they reached this point, they began promising clinical trials for their HIV vaccine.
Why is it so difficult to get the HIV vaccine?
Generally speaking, an HIV vaccine is challenging because our immune system is completely unprepared to fight this. For example, in the case of influenza and COVID-19 viruses, survival rates are very high. Many people resist infection because our immune system is ready to fight it. Vaccines are a huge help, but at least we’re protected they know when to start.
This does not happen with HIV. The vast majority of people infected will eventually die if they do not receive treatment. Our immune system is unable to fight it, and the reasons have long remained a mystery. Now, fortunately, we know what they are.
HIV is a real escapist. It has three mechanisms by which it evades the immune system. If one fails, you still have three left. The first one consists of hide the proteins of your shell that bind to receptors. For a virus to infect a cell, certain proteins must fit into cell receptors, like a key into a lock. Typically, vaccines are designed to attack these keys before they reach the front door. However, HIV has an incredible trick: it hides the key and takes it out only when it is already stuck to the lock. Thus, the immune system does not have time to recover.
On the other hand, it has sugar shield which blocks the arrival of antibodies. Even if they had time to attack when the key came out, they would not be able to do so because it would be very well protected.
Finally, the virus mutates greatly right in those areas that can be recognized by antibodies. By the time they know where to go, the virus has already changed and they will have to start all over again.
Role of broadly neutralizing antibodies
Broadly neutralizing antibodies are capable of attacking the virus. even if it mutates many times. Therefore, this last escape mechanism will be hidden. Moreover, if they can act quickly, the first barrier can be overcome. The second part remains, but people who generate them naturally seem to be able to avoid combining the virus, at least to a certain extent.
That’s why the results of this new study are so interesting. This is the end of the first phase of the clinical trial in which they took part. 24 healthy people. Four of them received placebo and the rest is an HIV vaccine. The goal was to administer four doses, but the study had to be stopped when one person developed allergic reaction to polyethylene glycol. This is the ingredient used to stabilize the vaccine. It is not required, so a new vaccine has been developed that does not contain it. Despite this, while it was being developed, researchers took the opportunity to analyze the results obtained so far.
At the time the trial was stopped, 5 people received 3 dosesand 15 more only 2 were assigned. Interestingly, the best results were obtained with two doses. It was these patients who developed a greater number of broadly neutralizing antibodies. One of them was able to attack from 15% to 35% of viral strains and it took only a few weeks to create instead of the usual two years.
What does this all mean?
It doesn’t mean we’re close HIV vaccine. A very promising step has just been taken. Moreover, following the same mechanism, the vaccine is expected to be improved so that it affects other conserved areas of the virus envelope, and the percentage of strains will be even higher. There have been other studies that reached phase 3 and were immediately stopped, so we should read these results with caution. But also with optimism. Cautious optimism is necessary in science.
Source: Hiper Textual
