 Types of vaccination. As we know that the vaccination or immunization is a process by which there is a specific protection provided against the common pathogens. So, on common pathogens against protection, how it will be given using the compounds or molecules or you can say that certain substances, those are called as vaccines. So, how many kinds of the vaccines there would be there? So, there are different variety. You can say that two modes of providing specific protection against many common and pathogens, common and damaging pathogens. It depends upon how we have just to combat those common and damaging pathogens. So, there are particularly these mode of immunization can be natural or artificial in their nature. Natural means that it is going to be activated or artificially that we have just to induce means in both cases the immune system is going to induce because immune system's induction will be, stimulation will be, so it will provide the protection. So, one production, one induction or stimulation is going naturally and one by artificial ways. So, how many ways of immunization are being there? There are two basic ways by which the immunization or vaccination process occurs. The first one is active immunization and the second one is passive immunization. Now, these two are different according to their nature that how they have just to perform their action. So, the active immunization as a name suggests that it is active form means is the induction of the immunity after exposure to the antigen. It means that the immune system's induction will be done in such a way that it is exposed by antigen. Agar to, because antigen is only one such thing which can activate the immune system. So, actively it can activate it. That's why we are using the term active immunity. Means antigen or microorganism which can directly activate the immune system that has the ability for active stimulation of the immune system. That is why it is called as active immunization. Now, the antigenic exposure is mandatory for such kind of immunization. Means without antigenic exposure, we can't say that active immunization we can achieve. So, antigenic exposure, it is mandatory. The active immunization can occur naturally or by exposing to microbe or other antigens. That means, I have told you that there are two ways to induction immunity that the immune system has to be induced. It has to be actively induced. Means, actively means that it has to be activated after exposing to antigens. Now, how can it be activated with antigens? There are two ways. One is naturally. Naturally, it can be exposed naturally to the antigens, to the organism. And the other is artificially. Artificially means that if we do it by ourselves by using the manufactured form of antigens or you can say a different variety of the pathogens. So, natural or artificial, these are two ways by which the active immunity can be activated. Now, it is also being important regarding active immunization that there would be no prior exposure before the entry of the antigen. It means, now before this, there would be no exposure before that antigen. Because if there was an exposure before that antigen, that means that immune system would definitely be activated before. But in this case, that means that there should not be prior exposure to the antigen. For example, it happens. Most of the cases, in case of infants who have more children who have an antigen exposure as compared to adults, it is less. So, that's why their prior exposure, their no experience in order to expose to antigen, that's why whenever they are going to expose to the antigen first time, they will develop the immune system against such kind of antigens or pathogens. So, there would be no pre-made antibodies. What does it mean? It means that against those antigens already formed antibodies will not be. Why not? Because they already have no exposure with such kind of specific antigen. So, if there is no exposure, how can antibodies come? Because antibodies are only there when they are exposed to antigen. Immune system, immune system will be activated, so antibodies will be formed. If they are already exposed, then that means the antibody should be there. But in this case, in case of active immunization, that means that the immune system should not have to expose to antigens before. And that's why as a result, they should not be pre-formed antibodies against such kind of antigens. Okay, the immune system develops the antibodies against the microbe, means antigens. The antigens that are entering the body or entering, what will they do? They will activate the immune system so that the generation of antibodies or antibodies start to be produced. So, those antibodies will produce, it would be a slow process of antibodies generation. Slowly, they are just going to develop. So, as a result, there is another important aspect of the immune system, that is the memory response. That memory response will come. Or antibodies remained in the blood or remained in the body for the longer time. That if next time, if there is any exposure, that antigen or that microorganism or that pathogen against, then antibodies always should be there. So, they have memory and that memory can protect them against such kind of pathogen. So, artificial active immunization, it can be achieved whenever we are just going to inject the microbe or before the natural exposure. That means, it has not been natural exposure and before natural exposure, if we inject it artificially in the body, then immune system will be activated and antibodies will start producing it. That is called as artificial active immunization. On contrary, you can say that treated microbes or toxins, they can also be used for the active immunization purpose. So, in contrast to the active immunization, there isn't a passive immunization. That means that induction of the active hemoral immunity. That in this, the activation of the hemoral immunity so that more than enough, what can be produced as antibodies? In this, antibodies are mandatory. The production of antibodies or the entry of antibodies directly by this process, it is very important. That's why it is called as passive immunization. So, passive immunization can occur naturally by the transfer of the maternal antibodies that are antibodies will go to the mother's fetus. So, that would be called as the natural passive immunization. On the other hand, it can be artificial induction that by injecting the gamma globulins which are immunoglobulins, antibodies which are already exposed to those antigens if they are injected into the other individual or animals who have been immunized against the antigens against the antibodies produced, if they are injected into the other individual, so that would be called as artificial way of passive immunization. Passive means that means this directly the antigen or the pathogen is not being introduced rather the antibodies produced in response are being entered into the body. So, those antibodies will protect against such potential pathogen. So, that's the difference between active and passive immunization.