HIV vaccine: latest news 2020

The article was prepared with the support of the site eleps.ru

Background

Some of the most important medical advances of the last century came from the development of vaccines to protect against viruses. Scientists have managed to develop vaccines against diseases such as:

• smallpox;
• polio;
• hepatitis A and hepatitis B;
• human papillomavirus (HPV);
• chicken pox.

However, there is a virus for which a vaccine has not yet been invented. The name of this virus is HIV .

HIV was first identified in 1984. At the time, the US Department of Health and Human Services announced that they hoped to have a vaccine within two years. But despite numerous studies, a truly effective vaccine has not yet been invented. So why is it so difficult to overcome this disease? And where are we now in the development of an HIV vaccine?

Why is it so difficult to develop a vaccine for HIV?

The difficulty in creating a vaccine against HIV is that the human immunodeficiency virus is different from other known viruses and requires a completely different approach to the invention of a vaccine.

The main difficulties in developing a vaccine against HIV:

1. The immune system of almost all people is “blind” to HIV. The immune system, which fights disease, does not respond to the HIV virus. It produces antibodies to HIV, but they only slow down the disease, not stop it;

2. Vaccines are generally made to mimic the immune response of people who have recovered. However, there are no recorded cases in the world where a person has fully recovered after being infected with HIV. Therefore, there is no immune response that an HIV vaccine can mimic;

3. Vaccines protect against disease, not infection . HIV is considered an infection until stage 3, that is, AIDS . Vaccines give the body more time to clear an infection on its own before disease develops. However, HIV has a long dormant period before it progresses to AIDS. During this period, the virus hides in the DNA of the person with the virus. The body cannot find and destroy all hidden copies of the virus to cure itself. Thus, in the case of HIV, the vaccine becomes powerless;

4. Killed or weakened HIV viruses cannot be used in a vaccine . Most vaccines contain killed or weakened viruses of a particular disease. However, killed HIV does not help develop the body's immune response, and any live form of the virus is too dangerous to use;

5. Vaccines are usually effective against rare diseases. For example, these include diphtheria or smallpox. But people at high risk of contracting HIV may be exposed to the virus every day. This means that the chances of contracting HIV are too high and the vaccine simply cannot prevent them;

6. Most vaccines protect against viruses that enter the body through the respiratory or gastrointestinal system. Most viruses enter the body in these two ways, so scientists have more experience in fighting them. But HIV most often enters the body through the genitals or blood. But today, humanity has less experience in protecting against viruses that enter the body in this way;

7. The HIV virus mutates quickly. The vaccine targets the virus in a specific form. If the virus changes, the vaccine can no longer affect it. HIV mutates quickly, so it is difficult to create a vaccine to counter this infection.

Preventive and therapeutic vaccines against HIV

Despite the obstacles listed above, scientists continue to search for a vaccine against HIV. There are two main types of vaccines: preventive and therapeutic.  

Most vaccines are preventive , meaning that they prevent a person from getting a disease. Therapeutic vaccines are used to boost the body's immune response to fight diseases that a person already has. Therapeutic vaccines are also considered treatments.

An HIV vaccine would theoretically have two purposes. First, it can be used on people who do not have HIV to prevent them from contracting the virus. This goal is preventive.

But HIV is also a good option for a therapeutic vaccine. Scientists hope that a therapeutic HIV vaccine will help reduce viral load .

Types of experimental HIV vaccines

Scientists are using many different approaches to develop an HIV vaccine. Potential vaccines are being developed for both prophylactic and therapeutic use.

Scientists are currently working with the following types of vaccines:

• peptide vaccines use small amounts of HIV proteins to trigger an immune response;
• recombinant subunit protein vaccines use larger fragments of HIV proteins;
• live vector vaccines use viruses to carry HIV genes into the body to trigger an immune response. The smallpox vaccine works on this principle;
• vaccine combinations use two vaccines one after the other to create a stronger immune response;
• Viral particle-like vaccines use a non-infectious analogue of HIV that contains some, but not all, of the HIV proteins;
• DNA vaccines use DNA from HIV to trigger an immune response.