Vaccines – How do they work and are they safe?

Hey guys! It’s Joerel again! Welcome everyone to a new segment of MedicineOnMyMind called Scientific Saturdays where I will be discussing either biological or biochemical processes inside or outside of humans or other organisms. This will be a once a month blog post, but there may be guest speakers whom will write about their own Scientific Saturdays blogs. In any case, we should start off with this first post.

Assuming you have read the title, today’s topic would be vaccines. We’ll be discussing what a vaccine is, how and why a vaccine works, and any dangers in having a vaccine. (‘Dangers’ is in bold because of the stigmas people associate with vaccines.)

What are vaccines?

Vaccines are dead or weak pathogens (which is done caused by chemicals – we’ll be talking about this later) and forces an immune response in your body. This is known as artificial active immunity; you do not physically the disease, but you do become immune to a specific disease by getting a weaker or dead version of the pathogen.

How does a vaccine work?

When a vaccine is injected into your body, there is an immune response to destroy the foreign pathogen. Essentially, a vaccine causes an immune response in our immune system in order to produce T and B Memory cells for that specific disease (or diseases if you have a three in one like the MMR vaccine). By doing so, this causes a quicker immunological response than if the ‘real’ pathogen (which is not weaker or dead) ever enters our body therefore we do not get sick at all and the symptoms are not expressed. The secondary immune response is so fast, if ever the real pathogen enters our body, the immune system would have the antibodies for the specific disease(s) due to the B and T memory cells present in our body.

Okay, but how does the immune system work on vaccines?

Well, when a pathogen first enters your body, your body is not aware that it is there. That is because the pathogen is miniscule compared to the other cells in the body. Nonetheless, a vaccine gives out several dead and weak strains of a certain virus or bacteria. Your immune system tends to use the phagocytes and phagocytosis to get rid of the pathogens. Macrophages, a type of phagocyte, is the first line of defence. A single macrophage can engulf and digest approximately one hundred pathogens. This process is called phagocytosis. What happens is the macrophage engulfs the pathogen via endocytosis, in which the pathogen is trapped in a vesicle called a phagosome. A phagosome would pair up with some lysosomes to form a phagolysosome, where the pathogen is digested but the antigens are not. The antigens are presented on the cell surface membrane of the phagocyte, which turns the phagocyte into an antigen presenting complex (or APC for short).

Another significant APC is your dendritic cells. These cells oversee choosing and picking of T and B virgin cells that reside in the lymph node. Your dendritic cells are important because these cells decide what type of immunological response you have during an infection. Dendritic cells become APCs by taking a sample of the pathogen via phagocytosis. When this happens, the dendritic cell then travels to the nearest lymph node, where it picks out a T virgin cell that has a complementary receptor on its cell surface membrane. When this happens, the T virgin cells become T-Helper cells, which rapid divide through the process of mitosis (proliferation / clonal expansion). These T-helper cells tend to divide into either killer cells that kill off pathogens, more helper cells that produce cytokines and interleukins for the stimulation of phagocytosis in phagocytes, the clonal expansion of B-cells or the stimulation of plasma cells to produce antibodies. Your T-helper cell then travels to the centre of the lymph node, in which they choose a virgin B-cell which has the similar receptor to the T-helper cell. How this happens is the activated T-helper cell signals to the virgin B-cells that has the same receptors to the T-helper cells. (This is a complicated process, so I’ll link to how this process works below, from the National Institution of Health.)[2] Either way, after the correct virgin B-cell has been chosen, the B-cells become activated B-Cells. The activated B-cell can either become plasma cells or the B-cells become B-memory cells, which remembers the specific pathogen that the plasma cells created antibodies for.

In the end, the antibodies produced by the plasma cells help the phagocytes engulf, digest and destroy the pathogen. But what is important is that the vaccine injected caused an immune response to produce T and B memory cells. This means you are immune (for a long while) for the specific disease and will never contract the disease(s) (for a long time or unless the pathogen mutates, so the whole process above must be repeated).

Dangers of vaccines:

Does anyone think vaccines are one hundred percent safe? Let’s talk about that.

You must remember that most vaccines must somehow either weaken the pathogen first, which means there are several chemicals that are used to do so. It would be wise prior to a vaccination to ask what is in the vaccine or to look up some of the ingredients used to make a vaccine. For example, you wouldn’t take a vaccine that had, for a weird example to highlight my point, nuts when you know you have an allergic reaction to nuts.

Most of the time, vaccines have certain chemicals which either prevents the reproduction of the pathogen when it is injected into you body or encourages your immune system to have a stronger response, so you are immune to the disease at a faster rate.

Most common chemicals used in vaccines are:[3]

  • Thimerosal (Ethylmercury) – This is safe, as this is broken down quickly in the body and is different from the ethylmercury found in fishes. Currently, there is no scientific link that this has any harmful effects, and this is ONLY added for the flu influenza.
  • Formaldehyde – While this may dangerous in large doses, a vaccine only contains a small amount of this chemical (0.02mg) and even then, formaldehyde is diluted into smaller amount during the manufacturing process.
  • Aluminium – After six decades of using aluminium, there has been no evidence that this causes any harmful effects on humans.
  • Antibiotics – This is most likely what causes a bad reaction in your body but manufactures of the vaccines ensure a strong antibiotic is NOT used and most of the time, they are reduced so there are negligible amounts in the vaccine.
  • Gelatin – While this is a major cause in causing allergic reactions, the incident rate is significantly small. If you think you or your child would have a severe allergic reaction (meaning if they do suffer from severe allergic reactions) then it is probably wise to choose an alternative method of immunity. Most of the time, this is relatively safe due to a small amount of Gelatin in a vaccine.
  • Monosodium Glutamate (MSG) – While there has been a small minority of short-term reactions, there are no long-term reactions link to MSG. The Food and Drug Administration, The World Health Organisation and the United Nations deemed MSG safe to use. (besides you guys eat some of this as a flavour enhancer in some foods so…)

Now you may think, even after hearing about what happens in your immune system and how relatively safe the vaccines are, that vaccines are completely dangerous, and you don’t want to put yourself or your child in that situation. But you have to ask yourself, am I really protecting me or my child by not having a vaccine? The answer is no.

Do you really think having natural immunity to diseases will somehow be safer than being exposed to a weaker strain or even dead version of a pathogen? Let’s take an example of measles.[4] Measles target your immune system, leaving you vulnerable to a secondary infection. You have the measles spots and pretty much can lead you to death and even if you do survive, your immune system is weak because of the measles virus that destroyed your immune system, so you’re still weak from the initial attack. Contrast that to taking an MMR vaccine, where you do not suffer from that attack and instead become immune without suffering any severe consequences like possible death. (To read up on possible effects, there’s a link on the citation which will lead you to the World Health Organisation’s information of people suffering from mild to severe effects. There is also one for the CDC’s review on vaccines. The numbers are low, but better to see it for yourself).[5] [6]

By not vaccinating, you are risking yourself and everyone else around you. The effect of herd immunity, where much of the population is vaccinated so the disease cannot infect many people to survive and ultimately leading to the extinction of the disease, decreases by not being vaccinated.

Vaccination is a good thing and a right to have. Don’t wait until it’s too late. If you’re travelling to a country where there’s a specific disease that’s prevalent in your area, ensure you get vaccinated for that disease before you travel, so you do get sick during your travels. It is better to be safe than sorry.

Thanks for reading, and I’ll see you next month for another Scientific Saturday.









Happy 70th to the NHS!!!

Last week, our NHS turned 70 years old! This is a huge reason for big celebrations, and we decided to do a little tribute along with the rest of the country. Some of the writers at Medicine on my Mind have written a small piece about what the NHS means to us. We hope you will enjoy reading our messages of gratitude to the NHS, and hope that this serves as a reminder of how privileged we are to have such a noble service available.

What the NHS means to me

Today is the 70th birthday of the NHS. 70 years ago, Beveridge described the National Health Service as providing care “from the cradle to the grave”. Though a simple phrase, the dedication, hard work and billions of lives saved within those lines are astonishing. From grandparent to parent to child, generation to generation, the NHS has provided an amazing gift to all of us. The gift of security in our healthcare, knowing that no matter what happens to any one of us, anything will be done to save our lives, as care is based on the clinical need of a patient, not the ability to pay. What makes the NHS so unique from any other nations health service, is the powerful values that underpin it. Values of inclusivity, compassion and the highest standard of care. Happy birthday, here’s to the next 70 years.

Jenna Philpott, Guest blogger for Medicine on my Mind


Until before I wanted to become a doctor, I never really gave much proper thought into how much the NHS does. It was just something that I knew was there when anyone needed it. But that is precisely what makes it so special. The NHS is there for whoever needs it, whenever they need it. They are always there—a bit like a parent. They tell us what to do just like a parent might: ‘smoke less’; ‘drink less’; ‘exercise to reduce your risk of cardiovascular inefficiency’. We try to pick fights and find faults in them, question them just like we may do with our parents sometimes: ‘The NHS is a victim of its own success’ or ‘the NHS is failing to meet targets’ or ‘Is the NHS still the “envy of the world”?’. But, they accept us no matter our background or circumstance, just like a parent does. And their hearts only wish the goodwill for us—just like a parent’s. At the end of the day, no matter what we may say, the NHS is an absolute privilege to have access to. Thank you so much to all the staff who make it so special and selflessly give so much of themselves to benefit the rest of us.

Muskaan Jonathan, Admin for Medicine on my Mind

Happy Birthday NHS!

In the 70-year course that this organisation has worked through, I must admit, it is doing well so far.

Now, I was not born in England – I was born in the Philippines and was brought to England around 2006. There are a few things I want to say about my experience with the NHS. I think that it is the light at the end of the tunnel. I believe many of us in the UK truly underestimate or do not appreciate the fact that the NHS provides free (to an extent) services for both adults and children. The NHS is something that I always thought just made sense? You know? Free healthcare?

Seeing other countries and their massively expensive bills for a consultation and surgery, (I’m looking at you America) it pains me to know that there are others who cannot actively seek help to improve themselves, to improve their conditions physically and mentally because of the fees and costs.

The NHS has helped me out so much in the ten years I have been here. I love the free dental care and the service they give, I would not have been able to get my glasses without them and they are improving by now focusing on mental health, which people undermine these days. The people who work there are selfless people who work around the clock to save lives, to comfort others and put their patients above themselves. We should not take these things lightly but rather help to improve.

The NHS is something wonderful and we should appreciate it because I do not know about you readers, but I would much rather get free health care than having to pay for one if the NHS is privatised.

Clement Attlee was the prime minister who helped establish the NHS, and his legacy and ideals give on in the NHS. He knew that change was needed so he delivered. We should support our National Health Service, and not lose this organisation that benefits not just one person, but everyone in the UK.

May the NHS and everyone who works there live on and prosper for many more years to come!

Joerel Gestopa, guest blogger for Medicine on My Mind

NHS Appreciation

NHS has been a vital part of many people’s lives, including mine. Some may even have had NHS since birth! That fact truly calls for a celebration. Imagine you, your child or your mum, anyone, playing a friendly game of football. One thing leads to another and suddenly – SNAP – a broken knee. A bit gruesome to imagine I suppose – but fear not: NHS comes to the rescue! The knee has been fixed, and at what cost? Nothing! Did you know that a surgery for a broken knee/leg can cost the NHS around £5,120? And you get it for free!

The NHS comes with much controversy, especially with the threat of privatisation – but today, let’s really think of all the positives and all of the things we brush off and disregard; things we are ungrateful for.

I admit, I myself have been guilty of debating about whether or not the NHS should be privatised. Yet the honest truth is, if NHS never existed, we may not even be alive! Just look back at UK’S history and why the NHS began! I believe that the NHS is one of the most unique, essential part, not only of UK’S history, but of its people. The wonderful service provided and the hard work being put in is something we truly cannot repay and wherever NHS goes from here, it will always be a part of us.

Antonia Jayme, Admin for Medicine on My Mind

Happy Birthday to our much-loved NHS!

By the writers of Medicine on My Mind

About Medicine on My Mind

We are a group of sixth formers in year 12 who are aspiring to be medical students. In order to help ourselves (and for the sheer enjoyment of it), we have set up this website as a place for us to post interesting things we find and think, relating to medicine.

The 3 admins of Medicine on My Mind are Muskaan Jonathan, Antonia Jayme and Bernice Mangundu, however, we do have some ‘guest bloggers’ who will post whenever they find something they would like to share. If you would like to be a guest blogger, please contact us via our email address or facebook page.

There will hopefully be a post every Tuesday. Please enjoy!

Do not hesitate to contact us if there is anything you find good or even bad: your opinion would be much appreciated in helping us to improve!