Why you should vaccinate

Smallpox is a very horrible disease caused by an airborne virus. The symptoms are severe lesions all over the body, especially in the face. That, combined with influenza-like symptoms and death. Historically the average mortality rate of smallpox is 30%, but there are more deadly variants of the disease (Belongia & Naleway, 2003). Estimations point that smallpox killed 200-500 million people during the 20th century alone. However, if you are born after 1979, chances are you will never be infected or even see the disease. Smallpox has been eradicated since of 1979, something we should be really thankful for. How? Vaccines (Belongia & Naleway, 2003). 

What is a vaccine?

Vaccines are drugs that are used to prevent infectious diseases. But how does it work?

We are surrounded and filled with microorganisms and viruses. In fact, the number of human cells in our bodies is in minority, the majority of cells are microorganisms. To protect our bodies from infection from all these viruses and microorganisms, we have an immune system. The immune system is divided into the adaptive immune system, and the innate or non-specific immune system. The innate immune system is like the first defense, skin barriers inflammation and also activates and aids the adaptive- or specific immune system

The adaptive immune system is a complex system with many different cells working together to fight infectious microorganisms. Essentially the two key cells involved are T cells and B cells. The T cells are filling several roles; killer T cells kill cells that have been infected by recognizing specific surface proteins called antigens, and helper T cells are mediators to help other cells. The antigens are the way that the immune system can differentiate between the human cells, and foreign cells. Once antigens of microorganisms has been detected, T cells are specifically programmed to kill off cells with specific antigens.

The B cells like T cells also recognize specific antigens that the infecting microorganism has. But the B cells produce antibodies, small molecules that recognize the foreign object and binds to it and coating it thus neutralizing the threat.

When the infection is fought off, some B cells and some T cells remain as long-lived B memory cells and T memory cells. These cells act as a catalog of all viruses or microorganisms that’s been infecting the body in the past. This allows the immune response to react much faster, so fast that you usually won’t experience any symptoms at all – you are immune.

This is quite a simplified explanation of the immune system, since it’s very complex I cannot cover everything here, but I encourage you to read about it, it’s quite fascinating.

The traditional vaccine contains an inactive form of a virus or microorganism, which is injected. The immune response will react on the antigen, form antibodies and remember the antigen for future, but you won’t get sick of the virus, because it’s inactivated. It’s like putting the virus identity in the catalog of memory cells without having to be sick.

The virus could be inactivated (inactivated, since viruses are usually not considered to be alive in the first place) by radiation, chemicals or other agents that kills the pathogen. But there are other methods; the virus can still be active or alive, but lost the ability to infect, or just parts (proteins) of the virus are injected. There are many more modern variations. The inactivated pathogen is quite old-school.

The success of vaccines

Center for Disease Control and Prevention (CDC) estimates that among children born in the period of 1994-2013 in the United States, 21 million hospitalizations and 732 000 deaths thanks to vaccinations (Whitney, Zhou, Singleton, & Anne, 2014). WHO estimates that 2-3 million deaths are prevented by immunization every year (WHO, 2016). The influenza vaccine can reduce the risk of dying by 50% among elderly (Nichol et al., 2003). We have eradicated smallpox, and polio is getting there. Eradication of diseases is one of the major accomplishments of humanity.

Herd immunity

If a critical mass of the population is vaccinated, the spread of a disease could halt (Anderson & May, 1985). One reason is that the probability of getting exposed to the pathogen – or contagious person – if not vaccinated is much lower if the majority of the population is immune. This is referred to as herd immunity, diseases being kept away from the population since the coverage of vaccinations is high. This protects people who are not vaccinated, people that have a compromised immune system such as chemotherapy patients, and people that are not able to vaccinate for other reasons (Anderson & May, 1985; Cesaro et al., 2014).

Reasons to vaccinate

The main reason to vaccinate is that the risk of dying or getting disabled from infectious disease is dramatically lowered since vaccines will protect against several severe diseases. Another important reason is to contribute to herd immunity. Maybe you will survive a disease that is possible to vaccinate against, but someone who has gone through chemotherapy might not. They will be protected if the population is vaccinated which reduces their risk of being infected due to herd immunity. Also, vaccinations prevents a large amount of illnesses and hospitalizations which saves a lot of resources from the health care system to be used for diseases that cannot be vaccinated against. Lastly, related to herd immunity, one contributes to eradication of diseases by vaccination, which will have long lasting effects for centuries. At least, I’m very thankful for the people that took the smallpox vaccine, so I don’t ever have to worry about smallpox. 

So what is the problem?

The reason why I’m writing this post is that as you might now, there are people who oppose vaccines for several reasons. My experience is that is far much common among vegans, and therefore I see it a lot. This could also just be confirmation bias, but anyway – that it exists is bad enough. I’ll try and list the main arguments or fears that I’ve seen and try to discuss them a bit.

“Animal products and animal testing”

This is probably the most sensible(but not legitimate, in my opinion) argument against vaccines. As a vegan one strives to eliminate all consumption or behaviors that involves exploitation of animals. Sure animal testing is horrible, but right now we don’t really have an option. I really want us to find a better options – and I’m pretty sure most people involved in development of pharmaceuticals want too – not just vegans, because animal testing is expensive business. However, abstaining from medicine and vaccines even in the reality of pharmaceutical development requiring test animals is not reasonable. Veganism to me means harm reduction, and “trying to suck less”. Since vaccines are literally saving hundreds of millions of lives, it’s not the lesser of two evils to abstain from vaccines. Removing the vaccines would result horrible amounts of human deaths and suffering – see prevention above. Removing animal testing without replacement is also highly unethical since that would also result in a dramatic drop in safety of drugs, which have direct effects of severe adverse effects, but also secondary effects of loss of trust in pharmaceuticals. The reasoning here for me is the same as that I would never discourage anyone from taking vital medication that is animal tested. When it comes to production of vaccines, I also think that GM-technology could help remove animal products from the production line.

“Vaccines cause autism”

Vaccines do not cause autism. This myth I believe started with the retracted lancet paper. In short, a paper was published in the journal The Lancet in 1998, linking the MMR-vaccine to autism. The MMR- vaccine is a combined vaccine against measles, mumps and rubella. However, the paper was retracted by the lancet (The Editors of The Lancet, 2010). The aftermath showed that the data supporting the link between MMR and autism was completely bogus (Deer, 2011). The publication in the lancet started research projects to evaluate if there really was a link, now we know, that MMR does not in any way cause any autism spectrum disease(Jain et al., 2015; Taylor, Swerdfeger, & Eslick, 2014). After the MMR fraud, unfortunately the number of vaccinated people in the UK started dropping, which resulted in an outbreak of measles, and several children died (Duffell, 2001; Jansen et al., 2003; Murch, 2016). This is a very good illustration of how dangerous vaccine opposition can be.

“Big pharma makes a lot of money”

 In comparison to the rest of revenue of pharmaceutical companies, vaccines usually make up quite a small portion. This is not were the companies make the most money. Actually, since vaccinations so dramatically reduce the number of hospitalizations, they would probably make more money if people weren’t vaccinated due to the medical cost in hospitals. Neither do I see the point in refusing vaccines that saves life since the manufacturer makes money out of it? A lot of companies make a lot of money on us. Also, the system we have today is that the pharmaceutical companies are the ones developing new drugs, and they need financing – profit from selling other drugs. Is there other ways? Sure, but boycotting vaccines is not the way to go (Lam, 2015).

The fear of ingredients

 Vaccines of course contain different ingredients other than the active ingredient itself. The ingredients I’ve seen causing worry among people that are afraid of vaccines are aluminum, formaldehyde and thimerosal (which contains ethylmercury). First of all, toxicity is just a matter of dose. Everything is toxic, but at different doses. Even water can kill a human if one drink too much too fast. When we say toxin in biology we usually mean something that an organism produce in the purpose of having a toxic effect on someone else, basically a weapon. In everyday life we call something toxic if the compound is toxic in relatively low doses.

Thimerosal is used in vaccines as a preservative to make sure that bacteria don’t grow in the vaccine. All mercury compounds are of course not equally toxic, and ethylmercury is not as toxic as for example methylmercury. Thimerosal has been assessed in regards of safety, and there is no concern of thimerosal having any toxic effects in the very small dose given in vaccines (Ball, Ball, & Pratt, 2001; Bose-O’Reilly, McCarty, Steckling, & Lettmeier, 2010; CDC, 2015b). However, since the most vulnerable to exposure are children, many childhood vaccines are now without thimerosal.

Aluminum salts are used in vaccines to enhance the immune response thereby improving the efficiency of the vaccine. These additives has proven to be safe for over 60 years, and is not the most common source of aluminum in our lives (FDA, 2014).

Formaldehyde can exist in some vaccines in very small amounts, one reason being that formaldehyde has been used in some vaccines to inactivate the virus. However, again, the dose is so small that it does not pose any threat. We even produce similar amounts of formaldehyde in our body, and vaccines are not the source of formaldehyde to worry about (FDA, 2014).

Conclusively, the extremely small threat that ingredients pose is nothing in comparison to the threat of the diseases they protect against. 

“Some people get sick anyway”

This is a severe case of nirvana fallacy. Sure, vaccines might not give 100% protection against the disease. But is that a case against vaccinations? By the same rationale, one should avoid basically all safety measures that we use. Seatbelts do not offer 100% protection against death in car accidents, would that be a case against seatbelts? Even a parachute does not offer 100% survival rate when jumping from a plane, but if I were, I would still want to use a parachute.

The fear of adverse effects

Almost all medication has adverse effects. This is because they somehow have an effect on the body in someway and the human body is a very complex thing. The idea however, is that drugs should act as a risk reduction. As the parachute and seatbelt analogue above, one could be strangled by the strings of the parachute, or experience a severe allergic reaction to the material of the seatbelt. But still, the benefit of using the vaccine far outnumbers the risk of adverse effects. Vaccines are considered to be very safe, and the adverse effects are usually very mild (Bonhoeffer & Heininger, 2007; CDC, 2015a). One should always compare the rates of the adverse effects to the rate of harm from the disease they protect against. Taking a vaccine is not about getting additional risks; it’s changing your odds. If you don’t agree, I challenge you to find a vaccine used today where the risk of adverse effects are more serious and more likely then the disease they protect against.

Additionally, when thinking about these numbers, one should take into account the estimated effect without vaccines, since vaccines can stop an epidemic. Comparing to morbidity rates in a vaccinated population against adverse effects is not a fair comparison. 

“Natural immunity”

This is something that really bothers me. Sure, if you survive a disease you might get immunity. However, that is if you survive. A lot of diseases that we vaccinate against have quite high mortality rates compared to other diseases. To choose to expose a child to a disease that almost certainly will cause suffering and potentially death instead of taking a safe modern vaccine is to me highly unethical and irresponsible. Some people actually get together to infect one and others children to provoke immunization, which is not only hurting children, but also actively promotes spreading of diseases. But I guess, when you’re dead you won’t be sick anymore…

“Not very dangerous diseases anyway”

This is simply not true. The diseases I’ve heard that is “not very dangerous” are mainly measles and influenza. Measles caused 2.6 million deaths worldwide prior to immunization programs. Over a period of 14 years, vaccination against measles is estimated to prevent 17.1 million deaths (WHO, 2015). I’ve also heard people claiming that deaths are caused by complications – implying other than the disease. Well, being a disease, measles cause complications. It typically happen in 30% of the cases (Atkinson, 2011). And of course there are other factors such as health status that could influence the risk of death.

Influenza is also not harmless. The seasonal influenza is estimated to cause around 500 000 deaths every year (WHO, 2014). Elderly and very small children are at particular risk but remember herd immunity. Also the severity of the influenza viruses are really hard to predict, they vary quite a lot. The Spanish flu that killed 20-100 million people in only two years was an influenza virus.

The resistance

In some way, the psychology of unwillingness to vaccinate could maybe be described as an analogous to antibiotic resistance. Both are posing a threat to public health where antibiotic resistance is an issue of overuse of antibiotic and a challenge for natural sciences. On the other hand, vaccine opposition also needs to be tackled for the well being of humans. Unfortunately nothing we do today to battle vaccine opposition seems to be working (Nyhan, Reifler, Richey, & Freed, 2014), even though one study found the opposite, we need to really make an effort to combat vaccine opposition (Horne, Powell, Hummel, & Holyoak, 2015)


Being against vaccinations do not make sense. Vaccinations are one of the greatest achievements ever, and are one of the most cost-effective initiatives for world health in combating disease. There is no rational reason to be against vaccines in my opinion. Unfortunately, the people who refuse vaccines seem to be the most resistant to facts as well, so it’s a real challenge how to reach out to the people refusing vaccines.


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Atkinson, W. (2011). Epidemiology and Prevention of Vaccine-Preventable Diseases (12th ed.).

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3 thoughts on “Why you should vaccinate

  1. Thanks for putting this together! This is a topic that really bothers me – just because I don’t eat animals doesn’t mean I’m anti-science which seems to be prevalent in the vegan community.


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