According to the data shared by the World Health Organization; Thanks to vaccines like measles, chickenpox and mumps as children, these diseases are almost never seen anymore. It is estimated that 2-3 million lives are saved each year thanks to these vaccines.
With technology, many things are developing in the field of health, such as treatment methods and vaccines. However, some vaccines have to be reapplied every year or at certain intervals. We have compiled the reasons for this for you.
In order to understand this, we must first learn how our body’s immune system works.
Our immune system is made up of different types of protective systems that work together to protect our bodies from harmful bacteria and viruses. These systems are divided into innate and acquired immunity.
Innate immunity is the immunity we have at birth. It consists of outer defense areas such as skin and inner defense zones such as cells. We can think of our innate immune system as the first responder in an emergency.
On the other hand, acquired immunity is the immunity that we do not have from birth and that we need to develop throughout our lives. This system is divided into active and passive. Since the system that concerns vaccines is active immunity, we will not talk about passive immunity.
Active immunity is the immune response of our body after exposure to a disease. These responses occur naturally as our bodies develop specific antibodies to fight viruses, or they can be created artificially through vaccines.
How does our natural active immunity protect us?
The interesting thing about our immunity is that it never forgets after the first attack. When first encountering a new virus, it takes time for the body to recognize the intruder and produce antigen-specific antibodies. This process can cause serious illness.
But after the immune system gains experience with a particular pathogen, it creates memory guard cells that keep the body ready for the next invasion. These memory cells initiate an immune response much faster and stronger if they encounter the same virus again. Thus, the chance of long-term protection from the disease increases.
So how do vaccines protect us against diseases?
Vaccines work by rebuilding memory as we mentioned above. Many vaccines accomplish this in different ways. But in the most basic way, most vaccines do this by inactivating or weakening the virus. When faced with a real virus, it produces antigen to reveal antibodies, just like preparing weapons before going into battle to provide protection.
The mRNA vaccines used for Covid-19, which we have recently, do not contain any viruses. But it works with the same basic purpose of generating an antibody response in the body in preparation for a real infection.
Let’s come to our main topic. Why do we need to get some vaccines every year and only once for others?
How long a vaccine will last depends on several factors. First, antibodies or defense systems don’t work forever and their rate of degradation is important. In diseases such as measles, this rate is relatively slow. This means that antibodies and vaccine-induced immunity remain durable for many years.
In some vaccines, such as tetanus and flu, antibodies are broken down faster. Booster vaccines should be given every year or at regular intervals to repair weakened antibodies and have a greater immune response.
Another factor affecting the protection of the vaccine is the constant mutation of viruses.
The more “stable” a virus is, the slower it is to reproduce, i.e. mutate. This gives us a great advantage. Measles is a stable virus that is unlikely to replicate. That’s why we don’t need to be vaccinated every year. Such viruses are almost destroyed by vaccination.
Influenza, Covid-19, and tetanus are viruses that can multiply rapidly and mutate a lot. For example, more than one new strain of flu emerges each year, which is why we need to get the flu vaccine every year.
We recommend getting vaccinated so you don’t get curable diseases or get sick again.
- Sources: Harvard Health Publishing, HealthMatch, CedarsSinai
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