To vaccinate or not?

Page content

To vaccinate or not?

TL;DR: Current vaccination rates against COVID-19 seem to decrease and there are indications that the vaccination coverage among adults could be less than 85 percent in a number of European countries. Why would a significant number of people not want to vaccinate themselves, especially now that millions of Europeans have already done so (mostly) without any serious complications? It is important to realize that there can be very valid personal reasons for this! But for most people the ethical choice seems to be to vaccinate, in order to protect the weak and vulnerable - which currently includes most children! Not doing so seems to indicate either misinformation - or very selfish behavior. Read on to find out if you can improve your own risk-benefit analysis, and make the choice that is right for you!

Disclaimer: Since I will be discussing some controversial topics here, I want to stress that I write in my capacity as a scientist. What that means is that my main interest in the following musings is to understand. I am not an expert on this topic, and if I learn more about it and come to a different understanding in the future, I will happily change my beliefs and opinion (and update this text correspondingly). Moreover, I have no immediate or hidden agenda here (at least not that I am aware of), and no conflicts of interest to declare (in other words: no one is paying, forcing, or otherwise motivating me to write this). I am trying to be neutral and apolitical. But of course my opinions and beliefs are shaped by values and concerns, only that these - to say that again - originate in what I think amounts to a professional, scientific mindset. Or to make this even shorter: I think the truth is important (even if it sometimes gives you a headache because it is so complicated).

It should also go without saying that the beliefs expressed here are my personal ones, and not in any way an official statement I would do in my professional capacity as a professor in a large university. (This is, among other things, since I am not an official expert on this topic but work in a different field.)

So, be nice and considerate. If you think I am wrong - well, it could actually be the case that you are right! If you help me to a better understanding, I will thank you.


The current COVID-19 situation has many aspects. It is easy to see only the enormous costs and losses, but we can also try to identify if there is something that we can learn from it, or if there is not some other important insight to be gained.

One thing that should have become clear by now is that we not only have agency, but that it also matters: What you do (or do not do) does have an impact. By being careful we contribute to making life not only safer for us, but also for others. Taking risks and engaging in unsafe practices can lead to complications for your family and acquaintances, but also for theirs, and for lots of other people you never met1.

On vaccinations

Vaccinations are a case in point, and the whole point of this article. What COVID-19 has been showing us in Europe, these last few weeks, is that a large part of the population is still not being vmaccinated. Statistics from the European Centre for Disease Prevention and Control2 show that after 30 weeks of on-going vaccinations only 70 percent of the adult population have received at least a first dose. Moreover, the rate of new vaccinations is getting lower and lower, which seems to indicate that we might not even reach 85 percent in most countries. From the public discussion in Germany (which I try to follow) it appears that this is not (anymore) due to availability of vaccines. Apparently a large part of the population simply does not want to be vaccinated.

Anecdotally, I had some discussions with acquaintances that have been sceptical about getting vaccinated. This post is partly a response to this experience, but also to help me clarify the situation for myself.

What interests me here is that the fraction of people not getting vaccinated seems so large - potentially a whopping 15-20 percent of the adult population! To me this is unexpected. Or not? I understand that there are people who cannot be vaccinated due to medical risks (more about that below). There is also “inertia”, or “transactional costs” as an economist would call this, which might keep some people from getting vaccinated in a timely manner. It costs time to make an appointment, to travel there, etc. People are not always rational and might be too busy or stressed to realize the importantance of the vaccination and reason (somewhat incorrectly) that there is no harm if they delay. But even if we account for this, there still seems to be a significant number of people who actively oppose vaccinations.

Of course this is nothing new. We see the same happen with “traditional” vaccinations for deadly diseases such as tetanus, although here the vaccination coverage amounts to around 95 percent of the population3. A more relevant example is measles, which does not seem so dangerous at first sight, and for which the coverage amounts to slightly more than 90 percent4.

One observation is that apparently the deadliness of a disease seems to be correlated with the vaccination coverage. Intuitively, this seems rational: assuming a constant risk of adverse effects from a vaccination but different risks of severe effects from contracting the disease unprotected, we would expect more people to willingly take that risk, when it decreases. At least, if we were to take a purely economic perspective, and would only care about our own indivual benefit!

Personal objections against vaccinations

There are other, highly personal reasons that can result in scepticism against vaccinations (or other medical interventions), and we should try to respect them. Some people think that medical interventions are unnatural and would rather let nature run its natural course. But it is difficult to accept this romantic viewpoint in extrema, as surely we would probably want to accept medical help during accidents? And maybe also visit the dentist regularly - to name just one example where most people usually require non-trivial medical interventions. When faced with a disease known for serious complications might maybe not be the right situation to study if your body can be the exception that can deal with it naturally?

Unfortunately I cannot find a reference, but if I remember correctly the singer Björk once said something to the extent that (and here I paraphrase from memory, probably badly):

many people have this very romantic image of the nature when coming to Iceland. But nature is - just nature. It does not care about you and will not magically provide for you if you make a mistake and end up in a bad situation outdoors.

To a lesser degree then, we can maybe accept that we should not try to avoid all diseases by any means, but that the occasional experience - or even just the possibility - of being (seriously) ill might be important and meaningful, at least to some people.

However, we should also realize that there are many, unbelievably many diseases, and we mostly developed and use vaccinations only against the ones that have potentially really serious consequences! What is somewhat new with the COVID-19 vacinations is that these consequences might be quite different across the population. So personally, indeed, most people probably do not have to fear too much from COVID-19. The problem - and why you should consider to vaccinate - is the other parts of the population that do.

Vaccinations and society

Individually, vaccinations are a gamble. Any vaccination has a risk of adverse effects. People can get seriously ill - or even die - from vaccine shots. That is an undisputed fact5. But it is also a fact that people can get seriously ill - or even die - from the disease that a vaccine protects against. And the chance of the latter happening is usually much, much larger than of the former. If we want to argue on purely probabilistic grounds this is already some indication that vaccines usually make sense. But - and this is a point that vaccine opponents point out rightly! - this is not enough information for a rational decision.

For an informed risk-benefit analysis and decision based on it, we also need to know the risk of actually being exposed to the disease. And this is where the discussion becomes an ethical, moral and political issue (if it was not already).

But let us start slowly. Consider tetanus, which is not a communicable disease. In other words, you cannot get it from other people, only from rusty nails, soil and dust, or other places where the relevant bacteria might live. The decision to vaccinate yourself is purely a personal one therefore. The risk of contracting Tetanus depends somewhat on where you live, what you do and how likely you are to break your skin, but is fairly high for most people. The risk of suffering catastrophic consequences is also very high, as tetanus is a deadly disease. The risk of adverse effects from tetanus vaccinations is low and virtually unknown. This usually makes the vaccination a no-brainer for most people. The important issue, though, is that this is primarily6 a personal decision. You yourself can weigh all those risks and take responsibility for this decision without having to consider other people’s lifes (apart from, maybe, people close to you).

Protecting the weak

The situation is different when it comes to communicable diseases.

The paradox that vaccine opponents are facing is that the less people are getting vaccinated, the larger the risks are getting, and therefore there is less justification for being opposed to getting vaccinated.

Usually vaccine opponents argue the opposite: Since the risk of getting the disease (and therefore of getting seriously ill or dying) is low, it can make sense to avoid the risks that the vaccination poses. But the more people believe that and act upon it, the less it becomes true!

It seems we could expect that the percentage of vaccine opponents reaches a certain equilibrium that reflects the balance between these different risks and how they are perceived. And although that is very interesting (there is information in these numbers!) it is unfortunately not the end of the story.

The key problems that make this an ethical and political challenge are:

  1. Vaccinations are not perfect. Even fully vaccinated people can become ill and suffer debilitating consequences from exposure to the disease.
  2. For some diseases, such as COVID-19, there are large groups of people that cannot be vaccinated because for them the vaccinations are too dangerous. This is on the one hand the group of immuno-compromised persons (which probably includes, e.g., cancer or AIDS patients, and people after transplations) and - most children (since it is deemed too risky to even assess the risk for them)! Indeed, there are some very worrying reports and indications about long-term effects of COVID-19 in children.

It is unclear to me to what extent vaccine opponents do realize the existence of these problems. But what these problems imply is that we should all try to avoid and limit exposure to SARS-CoV-2 as much as possible.

Afraid of the vaccine?

It seems difficult to understand the seemingly large percentage of active vaccine opponents. The most straightforward conclusion seems to be that people are fearing adverse effects from the COVID-19 vaccine more than from COVID-19 itself. Is there a reason to do that?

At first sight, this is counter-intuitive. The principle of a vaccine is to expose the body to an inactivated or otherwise weakened form of the disease itself. In other words:

If the body reacts badly to the vaccine, it would - with high likelihood - react even worse to the disease!

But there are exceptions. The following two come to mind:

  1. Common vaccines often contain additional chemicals (called adjuvants) that aim to increase the response of the immune system, in order to increase the protective effect7. It is known that some of these chemicals can cause adverse reactions. However, to my knowledge, such adjuvants are not used with common COVID-19 vaccines.
  2. Apparently one scientific study has seen that the adverse effects of SARS-CoV-1 coronavirus can be more severe after vaccination than without8. This is a very interesting and problematic phenomenon and indicates caution is necessary. However, this study was done on the SARS-1 coronavirus and its vaccines (and not for the SARS-CoV-2 virus that is causing COVID-19). And it was only studied in mice. It seems not relevant for COVID-19, especially with all the experience with the vaccines nowadays.

A major concern among vaccine opponents seems to be that the commonly used vaccines have not been tested sufficiently. And that there could be long-term adverse effects. Especially since many of these vaccines have been developed using the new mRNA technology. However, it should be remarked that mRNA vaccines have been previously developed and tested for a number of other diseases (e.g. HIV and Zikavirus) and are also being used extensively in treating various cancers - so there is already a substantial amount of experience with this type of treatment9.

Of course it is also true that vaccines were released for use after testing with a limited number of probands. For example, the safety of the Pfizer/BioNTech vaccine has been tested on around 40 000 people (of which half received the vaccine and the other half a placebo)10. For some people this might feel too small a number to trust in the safety of the vaccine - and it seems admissible, or even a good individual strategy to delay your own vaccination somewhat then and give the opportunity to eager “early adopters” instead (with a different risk assessment). However, now with the experience of millions of vaccinations, we should be able to trust the vaccines a lot more.

Long-term effects are difficult to understand, indeed, after only two years of experience with a new vaccine. However, it is difficult to see any indication of long-term adverse effects from any other vaccines either. In particular, I could not find significant indications of long-term damage from, e.g., measles or tetanus vaccine (although I have to admit that I did not check very carefully or searched long for it!). For other vaccines a few cases of concern have been documented, but ultimately the risk seems to be extremely low11. This makes it an unlikely risk also for COVID-19.

Finally, what seems to remain is the relative newness of the mRNA technology used to produce the main COVID-19 vaccines. Instead of breaking down and damaging a live COVID-19 virus, these vaccines use specific parts of the viral RNA and package them for delivery right into our cells. This sounds scary, but it is not more or less scary than what all viruses (e.g. also for the common cold!) do all the time - hijacking the internal machinery of our own cells for their own purposes12. Luckily RNA (either from viruses or from mRNA vaccines) does not enter the cell core. There is no mechanism for incorporating mRNA into our own DNA, and therefore RNA does not change our genetic information.

In fact, it is commonly believed that mRNA vaccines are, if at all, a lot safer than conventional vaccines - since most of the virus “program” is not present in the vaccine, only a very short, characteristic segment13.

The only other aspect that vaccine opponents use to argue against mRNA vaccines seems to be that these are sometimes considered genetically modified organisms (GMO). Being a heavily regulated topic, this depends on the definition of a GMO and sometimes even on what the vaccine is used for. It is clear that working with genetic information is not unproblematic. If at all, the European Union seems very strict and conservative (especially when seen in an international perspective). And yes, it is true that the EU has decided to deviate from their own strict regulations to speed-up and allow for the testing of COVID-19 vaccines inside the EU, even if some of these are formally considered GMOs14. Should that influence our decision whether to use the vaccine or not?

Virus variants

A major omission that I feel I have done is that I have so far not talked about mutations and virus variants. At least a short note feels appropriate.

This is somewhat simplified, but it should be clear that the more hosts a virus has access to, the larger the risk of further mutations. In other words, vaccinations not only protect weak members of our society, but also potentially protect against even worse or deadlier virus variants. This should also be considered.

Instead of a summary

Let me try to come to some kind of conclusion here:

  • Any vaccine has the risk of potentially severe consequences. Therefore it seems an ethical imperative that the decision to vaccinate should be voluntary.
  • That said, the risk of severe consequences from the disease itself is usually much, much larger. It seems difficult to justify not getting vaccinated on an invidivual basis. Even for a disease that - for many people - seems not very severe. Contracting COVID-19 will almost always do something worse to your body than the vaccine will. Still it is a personal decision, and people should have the right to take a personal risk if they are not comfortable with a vaccine produced by modern biotechnology.
  • Unfortunately there are large parts of the population that cannot protect themselves (including most children currently!). This makes the decision to not vaccinate somewhat problematic. The personal freedom and risk assessment of the individual (see above) has to be weighted with the danger to others. This is an ethical problem, and maybe even a moral one. The above discussion suggests that the ethical choice for most people should be to vaccinate - unless they have very strong and good reasons to be selfish. There is nothing wrong with that - although these reasons should be justified (and not due to misinformation or simply fear).
  • Being careful can go a long way in avoiding getting and spreading COVID-19 - but seems very unreliable without regular testing and contact tracing. A vaccine is a much more reliable means to protect yourself and others.
  • If really a significant part (10+ percent) of the population does not want to vaccinate, this seems to be a worrying sign. It seems to indicate that either many people are acting selfishly - without regard for the health and circumstances of others - or are irrational and probably afraid of the wrong things. The latter we can and should address with better information and education about the actual risks and facts. Here I think most governments and communities have lots to learn still…


  1. Incidentally, this is also something science has been trying to elucidate. Remember the “six degrees of separation” research on small networks, showing us that any two people on this planet are potentially connected through, on the average, six acquaintances only? This is of course not directly comparable to a virus traveling in a complex human world, but similar principles are at work also there, only that the degree of separation is probably (hopefully?) somewhat larger. ↩︎

  2. European Centre for Disease Prevention and Control: COVID-19 vaccine tracker. (accessed: 29-07-2021) ↩︎

  3. World Health Organization: Diphtheria tetanus toxoid and pertussis (DTP) vaccination coverage. (accessed: 29-07-2021) ↩︎

  4. World Health Organization: Measles vaccination coverage. (accessed: 29-07-2021) ↩︎

  5. It is very rare to die from a vaccination. In fact, there are simple measures to decrease that risk immensely, and which keep most, if not all people alive, such as the practice to wait 20 minutes after an immunization shot, being prepared for the appearance of an allergic reaction. ↩︎

  6. Your health care provider, health insurance, or government might of course disagree. It is a valid question any society has to ask itself how much individual lifestyle choices should be tolerated or policed, given that they do have impacts on other people. Even if that impact is quite indirect. Treating a preventable disease costs money, and - as some economists try to stress - money also means quality of life, and sometimes even life itself, to other people. To put it simply: Someone has to pay for the consequences of your decision, if it turns out badly. And that someone is - at least in Europe! - all of us taxpayers, primarily. So should we pay for every medical treatment necessary because of someone’s personal decision? Are we OK in paying for medical treatments of chain smokers and drug addicts? Are we OK to pay for the treatment of accidents? Even for base jumpers and vaccine opponents? ↩︎

  7. Centers for Disease Control and Prevention: Adjuvants and vaccines. (accessed: 29-07-2021) ↩︎

  8. Tseng et al (2012): Immunization with SARS coronavirus vaccines leads to pulmonary immunopathology on challenge with the SARS virus. PLOS One 7: e35421. DOI:10.1371/journal.pone.0035421 ↩︎

  9. Jackson et al (2020): The promise of mRNA vaccines - a biotech and industrial perspective. npj Vaccines 5:11 DOI:10.1038/s41541-020-0159-8 ↩︎

  10. Anand & Stahel (2021): The safety of Covid-19 mRNA vaccines - a review. BMC Patient Safety in Surgery 15:20. DOI:10.1186/s13037-021-00291-9 ↩︎

  11. Centers for Disease Control and Prevention: Historical vaccine safety concerns. (accessed: 29-07-2021) ↩︎

  12. Flint et al (2015): Principles of virology, Vol 1: Molecular biology. ASM Press, 4th edition. ↩︎

  13. Pardi et al (2018): mRNA vaccines - a new era in vaccinology. Nature Reviews 17: 261-279. DOI:10.1038/nrd.2017.243 ↩︎

  14. European parliament (2020): European parliament to allow COVID-19 vaccines to be developed more quickly. Press release, 10-07-2020. Available from: (accessed: 29-07-2021) ↩︎