As the world fights to eliminate the virus, it is time to ask how the future will be and how we will learn to live with it.In recent months, the questions have been focused on the vaccination campaign, their adverse effects and the body's immune response.On the other hand, the whole of the population that had overcome the virus by infection is made questions about the duration of the antibodies that fight it, its relationship with the severity of the disease or effectiveness in the norm established by health of receiving aonly dose to generate complete immunity.But what differences are there? What protects us most? How is the immune response generated?
When there was still no approved vaccine against COVID-19, many people claimed that infection was the best way to generate antibodies and immunize the virus.However, it is now known that even a person who has already passed the disease could be infected again, although it is a less likely case.
In a few months, Spain has achieved a vaccinated population index that already touches 70% of the population with full pattern.This invites you to reflect on how immunity we acquire, what is its effectiveness, its duration or if it is equivalent to that generated by natural infection.
Two types of immunity?
To understand how vaccines against COVID-19 act first to know how our body fights.When germs, like the virus caused by COVID-19, invade our body, attack and multiply.This invasion, called infection, is what causes the disease.In response, the fundamental elements of the immune system to deal with infection are two: antibodies and T and B cells.
-The antibodies
One of those who contain the disease in a serious way have high levels of antibody, while people who contract mild or asymptomatic disease have low antibody levels.However, the presence of antibodies does not always mean that the person is `` immune '' to a reinfection, although they are quite effective insurance that it is so.Antibody measurement is only part of the immune response, more complex in the long term.
First, to understand how the virus acts, we must understand its genetic composition.The coronavirus has four structural proteins: S, M, N and E.When the coronavirus infects us, our immune system acts in front of all the proteins of this virion generating specific antibodies against each protein (antigens).We generate four types of antibodies: - Anti -S - anti -m - anti -n - anti -e.Those that detect rapid tests are anti-n.However, induced immunity with the administration of the vaccine is different, since only one of these proteins is inoculated, the S.Therefore, the antibodies produced after injection are anti-s.
That is, vaccines do generate protection against infection, in fact, S proteins are those that return to the bloodstream and begin to manufacture new antibodies against the virus in case of reinfection.
Another difference is that antibodies produced naturally by your body in response to a vaccine, can last for a long time, but the antibodies produced in the laboratory usually last a few months, so it is required that people receive a new dose in a wayperiodic.
However, it should also be noted that the antibody levels acquired by a natural infection decrease over time.That means that the longer the infection, the less resistant it was a person to a second contagion.Therefore, vaccination is important, since the immune response neutralizes the virus and also offers us a very long term protection.
As explained in The Conversation, the antibodies that occur after immunizing with RNA vaccines better recognize the enemy than those induced by natural infection.And the same goes for adenovirus vaccines.Once again, it will depend a lot on the immune state of each person or, surely, on the severity with which the prior infection or exposure to new variants studied.
In spite.Therefore, the norm established by Health - once the infection has been overcome - to complete immunity with a single dose, has an empirical basis right.
In this sense, research suggests that the first dose in people who have exceeded the disease, produced a vigorous antibody response, similar to a serious natural infection, but the second dose did not provide an additional increase in antibody levels.This result is in line with the investigations that justify that in young and healthy people the second dose is not necessary if the covid has been passed before.
-Inity: memory cells T and B
The key to immunity is to know if despite the antibodies decay, the patient develops a complete immune response, which also includes the creation of white blood cells with memory, capable of remembering and eliminating the virus many months and even years afterEarly infection.
Vaccines help develop immunity by imitating an infection.However, such infection does not cause disease, but it does make the immune system produce T lymphocytes and antibodies.Once the imitation of the infection disappears, the body has a supply of T lymphocytes of '' memory'' and also of B lymphocytes that will remember how to combat that disease in the elofuturo.
In the case of having overcome the infection, these immune cells travel to the bone marrow and stay there in a latent state.If the virus reappears, the cells return to the bloodstream and begin to manufacture antibodies against the virus again.
In case of a reinfection, the secondary immune response allows each time a B lymphocyte meets a certain antigen, can immediately recognize it.Thus, they multiply, transform into plasma cells and produce antibodies.In this process, cooperative T lymphocytes help B lymphocytes.This answer is fast and very effective and avoids serious complications and even symptoms.
However, the body usually takes a few weeks to produce T lymphocytes and B lymphocytes after vaccination.Therefore, it is possible that a person who contracted an infection disease just before or just after vaccinating develops symptoms and contracting the disease, because the vaccine did not have enough time to provide protection.
Pros and cons
- Natural infection
Collective immunity can also be achieved when a sufficient number of people in the population has recovered from a disease and has developed protective antibodies against future infection.
But there are some important problems when trusting community infection to create collective immunity against the virus caused by COVID-19:
-Vaccines
Collective immunity can also be achieved when a sufficient number of people has been vaccinated against a disease and has developed protective antibodies against future infection.Unlike the natural infection method, vaccines create immunity without causing the disease or generating complications.
However, reaching collective immunity through vaccines can be difficult for many reasons.For example: