About vaccines

We live in a world that is changing as we speak. Apart from the technological breakthroughs that this era is associated with, we must be aware of the other factors in our lives that are also changing. Social life is changing, the way we see things is probably changing as well. In short, everything changes at a given rate. Everything includes medicine and health care- we have seen incredible advances that have saved lives or at least were a sign that we are going to get to that point. Getting people to act and benefit from such things seems, in theory, easy and even unnecessary-who wouldn’t want to benefit? In real life, that question does have long answers that can be viewed from different points –some people don’t want to and others would want but cannot (again, due to a variety of reasons).

When talking about advances in medicine and healthcare of the past century we have to consider vaccines. Whatever views you may have you can’t say that the science and the work behind developing a vaccine are not important. Yet, no medical procedure is in theory unable to lead to
side-effects, unwanted reactions or other diseases and so vaccines pose questions as every other element, whether it is a method or a drug, for example. These questions need answers and while sometimes they fail to come in time, the consequences become visible soon enough.

The reason I decided to write a post about vaccines, immunization and perception is the amount of buzz around the recent measles outbreak in the US and most importantly, a conversation I had with a person.  I’m going to give an overview (not too detailed-just to get everybody to understand) of the things mentioned above and then present my opinion on such situations . Of course, being informed about vaccines, the diseases that can be prevented with administration (including the side-effects and the potential threats of an actual infection with a particular disease) and whether a person should have the vaccine taken or not is a matter of choice in most cases. This is one reason why information is crucial and it should not be manipulated- information that a person gets about such topics should be as accurate as possible and to set things straight-Everybody should get informed and think.

What is a vaccine? A vaccine is a composition that leads to active acquired immunity for a certain disease. Before talking about the composition, clarifying a few terms like         natural/acquired or artificial and active/passive immunity is necessary. Immunity is that situation in your body when you have the ability to fight infection, disease, or other unwanted invasions by pathogens, with tolerance while not facing  inflammation, allergy, and autoimmune diseases. When we talk about natural active immunity, the person's body makes the antibodies: the normal pathway is followed: the body encounters a pathogen(disease-causing organism) with a foreign antigen and the immune system/response becomes active and makes the antibodies that would result in the destruction of the pathogen. There are certain cases in which we talk about natural passive immunity-a good example would be that of the unborn baby that receives antibodies from the mother through the placenta or after birth from milk-it provides temporary immunity and the baby's body does not make the antibodies in question. On the contrary, acquired or artificial active immunity is the basis of vaccines in general. The vaccine is used to generate immunity. The immune system produces antibodies against the antigen of the pathogen(for example polio) and memory cells will be made so if the body comes into contact with the active antigen(as the ones used in vaccines are attenuated, for example),the respective antigen will immediately be destroyed without the lengthy immune response having to take place(which would happen if the vaccine had not been administrated). The natural response we have is very effective and nevertheless, still we do get ill from time to time. Why? Because although it is effective it can take some time for it to become fully active and combat the intruder with full force.

There are several ways to make a vaccine generate immunity-there are types or vaccines-

•          Inactivated -which consist of the virus particles(antigens) the actual viruses having been killed (with heat or formaldehyde( CH₂O , also known as methanal), being the most common). The viruses are grown under strict conditions and as they are killed they are classified as non-infectious.Examples include the polio vaccine and the influenza vaccine .Large doses( as repeated administration) are required along with adjuvants which are helpers that boost the response to give a higher amount of antibodies or a longer protection (in some cases) in order to confer immunity. The repetition of administration is due to the fact that inactivated, the microbes are not that efficient at stimulating a desired response the first time.

 These contrasted with attenuated vaccines. => killed=attenuated

•          Attenuated vaccines are those that contain live, attenuated microorganisms. Most of these are viral so they are used in case of a disease caused by a virus. The viruses are cultivated in different conditions than that of their usual preferred cell for infection that enable them to cope and survive yet, because they do so the pathogens lose their virulent/disease-causing properties. In other words, they are able to cause the immune response of the body without actually producing damage. For one thing, these vaccines are not given to immunocompromised individuals (people that may have certain problems with their immunity response/system). These vaccines have advantages and disadvantages-you might want to read more about that –for example: it may provide more durable immunity but in contrast can cause severe problems in immunocompromised patients, as mentioned above. Why? Because their major disadvantage is that some viruses do change back and become the threats that we wanted to avoid.

Examples include the measles vaccine and the BCG vaccine (vaccine against tuberculosis).

    •        Toxoid vaccines -made from inactivated toxic compounds rather than the whole organism. Examples   : tetanus and diphtheria. The toxic compounds are those that would result in case of infection but they are not allowed/able to induce the problems correlated with the disease, again, they are utilized just to prepare the organism to act fast in case of a real encounter.

•          Subunit vaccines : a fragment of an microorganism is used to get the immune response

•          Conjugate vaccines

•          Experimental vaccines

•          You can find more about the different types of vaccines by visiting Wikipedia and other sources like scientific journals, sites like http://www.vaccines.gov/more_info/types/ (which is described as A federal government Website managed by the U.S. Department of Health and Human Services)

 How does the pathway of immunity actually looks like ? Focusing on the humoral response, it involves several stages. The first thing that happens is the arrival of the disease-causing organisms that enter our body or at least come in contact with parts of our body for enough time to be taken into consideration by our immune system. Different types of cells come in to play after this-macrophages being very important. These cells engulf the pathogen by phagocytosis (enveloping it into parts of their membrane so they can be taken inside the cell) and start to process it. You might already make a connection-by taking the pathogen inside the body's system evaluates the actual element. At the end of this process, the proteins that were originally part of the pathogen and which are called antigens are exposed on the surface of the macrophage-at this point we are talking about a special type of cell-an APC-Antigen Presenting Cell. From now on, T cells and B cells take over the process. T helper cells recognize the APCs and the CD4 complexes(glycoproteins; proteins that have a carbohydrate part in their structure) bind in order to release substances that would later activate the B cells. These are not the ones that originally make the antibodies but they do have their role as they later make plasma cells, the final player of the game that is the antibody factory.

With reference to what the natural pathway of immunity involves, we can now say what the vaccine does- it provides the substrate on which the immune system can work on , resulting in T memory cells and B memory cells that are proven to be really helpful. Then, are they toxic, ineffective or the cause of inexplicable phenomena(like autism)? Many of these questions have puzzling answers that may or may not be understood by many people, leading to decisions such as not vaccinating children because of the fear of any side-effects that have been reported. In this case I'd say an expert should be consulted because scientific studies that might try to prove links are not always reliable or valid and not everyone is capable of interpreting the data. At the same time, something like a drug or chemical is not always toxic for the body unless taken in over certain amounts. Even sugar(I'm going to refer mostly to glucose) is needed to survive but without control it can do more damage than good and the thing which I actually wanted to point out is that some people are more susceptible to problems that deal with glucose(for example) than others. A vaccine is not to be looked at as a single molecule but the same thing applies to their action: some people react well to them and some do not. The reason seems to be the genetic makeup of a person( which controls metabolic pathways that include breaking down compounds). Moreover, that is not the complete story. New studies have claimed links between the microbiome in our guts and the immune system as well as behaviour.

Another topic which I wanted to address is the one of herd immunity. Herd immunity refers to the situation when the majority of people are protected from a certain infectious disease( by vaccination) so the other individuals that are not are less likely to become infected as the pathogen would not, in theory, propagate through the population because of the previously mentioned acquired immunity. Theoretically speaking, if you have a low number of people that have not received their vaccines the chances of infection are remote because the chances of coming into contact with the pathogen are remote as well. Sadly, the situation seems to be changing these days, with more people counting on others to vaccinate their children or simply not vaccinating, having heard stories that ,to put it straight, have freaked them out. I understand that giving consent for such a procedure for a child is a lot of responsibility and involves a lot of stress. But when it comes to deadly diseases( with vaccines that have been long used) for which vaccination is recommended and consent is not given I think that the parents do not evaluate the risk well enough-when vaccines are recommended or necessary they are presented as such because the overall benefits outweigh the risks involved.

All in all, there is more than one type of vaccine but they all have the same aim, to prepare the body for immediate action in the case of infection. Also, opinions differ but these should be formed with a good amount of information and the risks of both sides should be assessed accordingly. I hope that this post has sparked the interest of the reader and encouraged him or her to look for accurate, reliable information when deciding what to do when it comes to evaluating vaccines as well as when giving consent.

                                                 Cristina

*all the links above are mentioned purely for informational purposes;