Hello! I have been a doctor for 21 years. My name is Georgy Olegovich Sapego. In this article I will talk about herd immunity in diphtheria.
The idea of the impossibility of herd immunity in the case of diphtheria came, as it seems to me, from one neighboring country, where there was no vaccine. It is easy to get confused here, because with diphtheria, it is not the diphtheria bacillus itself that is dangerous, but its toxin. The toxin is terribly poisonous. People die from it.
Children are vaccinated against diphtheria at an early age, and adults every 10 years.
The peculiarity of the vaccine is that it teaches our immunity to fight the toxin. Immunity produces antibodies that block the toxin. Well, the diphtheria bacillus itself may die, or it may survive. They don't chase her too much.
And then such a painful idea appeared. Some people think that, like, it is not necessary to be vaccinated, because immunity against bacteria is not is produced, and in case of illness in the hospital they will still inject a magic serum and block toxin.
Explain
In addition to the diphtheria bacillus, which secretes the toxin, there are also bacteria that do not secrete the toxin. They may have a common sore throat or something similar. People can carry both dangerous bacteria with a toxin, and not very dangerous without a toxin. These bacteria can be secreted by humans and infect others. You and I know how to live peacefully with several sisters of these diphtheria sticks.
If you vaccinate a large part of the population, then the bacteria with the toxin will slowly disappear. They are replaced by similar but not dangerous ones. It is a fact. That is, if people properly vaccinate children and themselves, then poisonous bacteria go away. This is the very same herd immunity.
Why are they leaving?
In the case of diphtheria, herd immunity mechanisms are complex. The simplest explanation is the spitting of disgusting films from the throat by the sick. The more severely people get sick, the more chances that pieces of meat with diphtheria rods will fly out of them, the more people around them will spit, and the more the infection spreads.
If people are vaccinated, they do not get sick, do not cough up their throats, do not infect others, and do not support the bacterial population.
Another explanation is more complicated. It is believed that vaccination against diphtheria raises the general level of immunity, and the body copes better with bacteria.
The next explanation is even more complicated and involves bacteriophages.
Bacteriophages are viruses that exclusively attack bacteria. They, like the viruses we are familiar with, are embedded in the DNA of these bacteria. The trick is that bacteriophages do not just reproduce themselves with the help of bacteria, but they can take something from the bacteria. Sometimes they take information about the toxin from the bacteria.
If such a bacteriophage attacks a harmless bacterium, then it can transmit to it a secret recipe for a dangerous toxin. It turns out that the poisonous diphtheria bacillus not only reproduces itself, but it also sends letters to its relatives with detailed instructions on how to make the toxin.
If many people are vaccinated against diphtheria, then for some reason there are more bacteria that are not susceptible to bacteriophages. Evil diphtheria sticks cannot send letters to relatives, they find themselves without the support of relatives and are slowly dying out. This leaves people with mostly harmless bacteria.
Sometimes they come back
Here we need to clarify something. The vaccine does not create immunity against the diphtheria bacillus itself. If this evil bacterium is brought from abroad, then it will easily cause diphtheria in people without immunity.
They say that this happened in the 80s in our country and in the 2000s among the Americans. In both cases, it was associated with the fighting in Afghanistan. This is the homeland of diphtheria, and servicemen returned home with the infection.
It turns out that there are two reasons to get vaccinated:
- The infection can be delivered at any time, and you need to be ready for this.
- It is necessary to create collective immunity, and then the infection will not be able to live in our home.
Do you get the diphtheria vaccine?
