Sthe immune system helps us not get sick and fights infections. It has several components.
The immune system takes action when we are exposed to a disease, whether it is caused by a virus, an infection or a fungus. To fight these invaders, our body releases chemicals and white blood cells.
But the immune system can also give a targeted response against certain viruses or bacteria, producing specific antibodies – proteins that catch the virus and prevent it from entering.e in the cells and T lymphocytes, which destroy already infected cells.
But if we are exposed to a new virus, such as SARS-CoV2, or any new virus we have never encountered, the immune system needs more time to know how to react.
If we already have antibodies to a virus we have been exposed to, they are sent to battle when that virus reappears. This is how acquired immunity appears. The same principle is used for vaccines.
If more people are vaccinated or gain immunity to a virus, it is much harder for the population to get sick, because there is collective immunity.
But the development of antibodies after exposure to a virus or after vaccination does not mean that we are completely safe from a new disease or that we will be protected for life.
Some viruses, such as measles, leave a strong “memory” for the immune system, and if we got the disease or were vaccinated, we will have antibodies for the rest of our lives. But other viruses, such as the one that causes the common cold, are “forgotten” very easily and we can catch a cold again only after a few weeks.
Other viruses, such as the flu, invade our immune system through repeated mutations.
However, there is no evidence that the new coronavirus has mutations fast enough to need different antibodies in case of new exposure. Because it’s so new, we don’t even know how “memorable” it is for the immune system. It is not clear what the link is between the severity of the disease and the level of antibodies acquired.
In some cases, antibodies can protect us from a serious form of an infection, but we can make a mild form.
Finding out about these things would help scientists find out how – and how often – people should be vaccinated against the new coronavirus. We could also find out if a positive antibody test can be considered as proof that we have acquired immunity.
Web editor: Monica Bonea