Vaccine

Back in August I started a discussion about Vaccines, every week I posted a little bit more about this massive topic. I really enjoyed going through this content and sharing it with everyone on the Facebook page but I kept losing it in the thread so I thought I’d load it up here and get everything all in one place with a few tweaks to help the flow.

Enjoy

So, I want to talk about vaccines.

It can be very easy to get bogged down with over 3,000 years of human experimentation and scientific investigation. So, there’s a few things I need to say first.

  • There is far too much to talk about in one go
(post, week, month or year) I’m going to break it up over regular intervals and try to give you all some basic info and some places to look for yourself.
  • This page and group is designed to encourage and engage the Ballarat community in scientific topics. In an approachable and friendly manner. It’s not about who has the loudest voice. Any comments with insulting language will be removed. Encourage each other to learn.
  • If you have a question.  Ask it. If you have an answer or a logical argument. Provide evidence to support it.
  • Your point of view, as best as possible, will be held up to the rigors of the scientific method. If it cannot stand up to this it will be refuted. Provide evidence.
  • Be nice. Not everyone knows what you know or how to go about finding out more, help each other.
  • Science not politics.

Let’s get to it

The History of Vaccines

One of the amazing things about our species, is that we can pass on our collected knowledge. It’s how we have progressed and thrived for so long. It allowed us to collaborate and trade, to learn the language of foreign lands. For more than 3,000 years the Chinese, Indian, Greek and Egyptian civilisations enjoyed the benefits of trade and commerce, something they didn’t enjoy, but shared just the same, was smallpox. A plague virus which was only eliminated in 1980.

louis-pasteur

Louis Pasteur, who is credited with creating the vaccines for chicken cholera, anthrax, and rabies, is shown in his laboratory.

That leads us to two questions, What’s a virus? And. What’s a vaccine?

Virus

Let’s start with what a virus is and how it works. Without going into too much detail.

There is an estimated one million (minimum) different viral organisms, across all species of vertebrates. Not bad for something that isn’t technically alive.

A virus is referred to as a non-cellular organism, this means it doesn’t have the ability to reproduce on its own. Instead a virus will ‘hijack’ a host cell and will typically replace the RNA instructions of the cell with its own. (RNA is instructional information required by the cell to replicate and ‘print’ that organism’s DNA chain.) Once this process begins the hijacked cell stops its normal operation and begins building more viruses ultimately the new virus cells burst out of the host cell killing it and spreading to neighbouring cells to start the process again. The fact that it cannot reproduce by its own means and requires a host to do the work, is why it not technically alive.

But what happens to your body when your exposed to a virus?

The human immune system.

For that let’s to look at how your immune system works and why vaccines are used to increase your body’s immune response.

Any biological agent which causes disease or illness is referred to as a Pathogen, this includes; viruses, bacteria, fungi and parasites, (pollen and some chemicals affect the body’s immune system as well.) Each pathogen has on its surface a unique protein chain known as an antigen.

In the presence of these antigens, the immune system responds with white blood cells called lymphocytes which create the antibodies to combat the antigen. Antibodies are large y-shaped proteins that seek out an
d bind to antigens killing off the infection. They are unique built for a single purpose. If the immune system has never encountered an antigen before, it must fight the infection to learn how to beat it. (This is when you get sick). In some cases, your body is simply not able to withstand this battle.influenza-virus

However, if the immune system HAS encountered the antigen, it remembers and can issue the order to create the appropriate antibodies needed to kill off the infection. (This is when you don’t get sick.) The important thing about this is, the immune system doesn’t care how it learns which antibody to make. You can recover from an illness, or you can get a vaccine. So long as the immune system knows what it’s looking at it can take care of you. Another way your body normally gets introduced to antigens and learns to create antibodies is while you’re a baby and you put basically everything you can find in your mouth. Kids kind of need to chew on everything they find and play in the dirt. It’s good for their immune system to be introduced to these everyday antigens. The only difference between how an antigen is introduced, is that through vaccination you can get that immunity without the illness.

Vaccines don’t just stop pathogens though; some viruses have also been liked to other issues. For example, about 20% of all cancers are thought to be caused by a viral infection. Such as with the HPV virus and cervical cancer. Since the implementation of the HPV vaccine 10 years ago, there has been a stunning 187 million doses of the vaccine administered globally reducing the infection rate of HPV by 90% in some instances. That’s a massive reduction in a virus which causes 70% of cervical cancers.

Okay, so what’s a vaccine then?

Types of Vaccine

Broadly speaking a vaccine is a form of preventative medicine which improves your immune system allowing it to fight off a pathogen with out you suffering from the associated disease. Once again, this subject is massive. If someone tells you they can explain it all in one go be very sceptical.

There are several classes of vaccine these include:

  • Live attenuated vaccines
  • Inactivated vaccines
  • Subunit vaccines
  • Toxoid vaccines
  • Conjugate vaccines
  • DNA vaccines
  • Recombinant vector vaccines

Let’s look at two of the main ones and you can follow the links in the bibliography to find out more.

Live Attenuated Vaccines

(LAVs) are “tamed” version of a wild virus or bacterial strain which has been weakened by selectively culturing the organism over successive generations, to be more susceptible to a host immune system. The measles vaccine is a good example of an LAV, which was cultured form a sample taken from an 11 child in 1954 then subjected to multiple hostile conditions resulting wreaking it to the host immune system. LAV’s are made so they can replicate themselves once they have entered a host but do not generally cause the illness normally associated (if they do it’s a very mild case.) However, LAV’s are sensitive to heat and light requiring extra care and refrigeration for their transport.

Inactivated Vaccines

Unlike live attenuated vaccines inactivated vaccines do not contain any live antigen component. The organism is then killed using heat/chemical treatment, meaning it is no longer able to replicate its self. This means that a larger dose of the antigen is required to provide the immunity, it also requires periodic booster shots to be administered.

The CDC produced document ‘Principals of vaccination’ (see link) gives a good rundown of the basics and other kinds of vaccines. If you’re interested in some heavier reading you can check out some peer reviewed journals like, Nature. A peer reviewed journal has been reviewed and scrutinised be group of academics who usually specialise in the contents field. (check out my earlier blog if you want a refresher on what a peer reviewed paper is.)

What’s in a vaccine?

Well, 2500-3000 years of research, experiment, and understanding, so quite a lot. And unless you have a chemistry degree the ingredients aren’t going to mean a whole lot to you.

The components of a vaccine include:

  • The Antigen of whatever is being introduced to provide immunisation.
  • Preservatives to keep the vaccine viable for as long as possible.
  • Adjuvants to help boost the immune response and get the antibodies up and running.
  • Stabilisers, to make sure as much of the vaccine antigens are administered as possible.
  • Diluents, like sterilised water or saline to fill out the volume of the vaccine.
  • Residue from the production process, a minuscule amount of chemical that is used to sterilise or process the antigen.

I think these are the bits that people most often misunderstand, mainly because there is a whole lot of chemistry going on here and it’s easy for the lay person to get confused. Or have someone tell you that a chemical compound is dangerous.

To be clear, if your doctor gives you a vaccine, to the overwhelming majority of people out there, it’s completely safe. Not for everyone, there are legitimate adverse reactions out there. If you’re concerned talk to your doctor, you can ask for the info sheet that comes with a vaccine next time you get your shots. While it won’t mean much to you ordinarily, it does allow you to spot anything you know you’re allergic to. The influenza vaccine for example, is typically produced using eggs, which can cause allergic reactions in some people. As can some of the other chemicals used in the process, that’s why the full list is included. You can also contact the National Centre for Immunisation Research and Surveillance. Who are tasked with monitoring adverse vaccine reactions.

Do vaccines really, work?

Yes, yes they do.

Vaccine have successfully eradicated several very serious infectious diseases, like polio and small pox, the HPV vaccine has reduced the rate of infection in some locations by as much as 90%. That almost whipped out a virus which almost every other person will contract in their lifetime, and which is responsible for 70% of cervical cancer and 5% of all cancers worldwide. A global inoculation coverage around 85% against the measles virus has reportedly saved more than 20 million lives between 2000 and 2015.

Yes, there are often side-effects to vaccines but these are typically mild. Side-effects from the MMR (Measles, Mumps, and Rubella) vaccine include; Mild problems such as fever or a mild rash. About 1 in 6, and 1 in 20 respectively. The MMR vaccine is not a live vaccine so it takes several rounds to be fully inoculated, if these adverse reactions do occur, they are often less noticeable after the second dose. Serious allergic reaction have been reported after the vaccination a child with the MMR vaccine, including: Deafness, Long-term seizures, coma, or lowered consciousness, Permanent brain damage. However, these are so rare (less than 1 per million vaccine doses) that it is hard to tell whether they are caused by the vaccine.

And just so we’re clear, there is no credible evidence linking vaccines to Autism. It is utterly false to say otherwise.

Conclusion

So, to recap, there is a staggering amount of human time, knowledge and study that has gone into researching and refining vaccines. We’ve had a good overview look at some the subject matter, there’s a small library’s worth of links, articles, papers and other credible sources of information for you to peruse through.

If vaccines are something that you’ve been made to feel scared of, I implore you to have a look at what I’ve collected here. I’ve taken the time to track down credible sources and quality information, but please don’t just take my word for it. Talk with your doctor, talk with someone else’s doctor, one of the goals of this blog and the Ballarat Science in the Community project is to help you improve the skills needed to figure this stuff out for yourself. To figure out whose opinions are relevant. To empower.

If there’s anything which you think I’ve gotten wrong, that I could improve or clarify, or if you would like to clarify something. Please do, I want to have discussion with people and encourage others to discuss.

Until next time.

Ask your questions, support your opinions with evidence, discuss, edify.

Bibliography

History of Vaccines

Virus

Human Immune System

Types of Vaccine

What’s in a Vaccine?

Do vaccines work?

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