Kurzgesagt – In a Nutshell

Sources – Vaccines

Vaccines and their side effects are a hard topic to cover – we know we keep saying this, but in this case especially, there were a lot of things to consider. You can’t blame people for being worried, so we wanted to take their concerns seriously.

Because it is impossible to cover everything there is to know about vaccines in a ten minute video our sources are extra extensive and explain a lot of aspects in more detail, with extra focus on further reading.

So if you want to dive in deeper or have more arguments at hand for your next heated discussion, here you go.

A huge thanks to the following scientists and experts for their help with this video:

  • Matt Hanson

Senior Program Officer, Bill & Melinda Gates Foundation

  • Hannah Ritchie

Researcher at Our World in Data


(They have interesting stuff on all kinds of topics. Don't miss to check it out!)

  • María Bertoglia

Assistant Professor, Research epidemiologist

University of Chile

  • Anonymous

Member of the Oxford Vaccine Group

  • Anonymous

Member of the Oxford Vaccine Group

  • Anonymous

Science writer at MPLS


– Your immune system is a complex army of billions of cells.

#How the immune system works, retrieved 2019


#Overview of the Immune System, 2013


– You know these weapons: Antibodies.

#Antibody, retrieved 2019


– Unfortunately this process takes several days to complete.

#Immunobiology: The Immune System in Health and Disease. 5th edition. Principles of innate and adaptive immunity, 2001


– Our immune system automatically creates so called memory cells.

The easy version:

#Memory Cells, retrieved 2019


The techy version:

#Immunological memory cells, 2018


– We can avoid harm from the injected invaders by killing them or by ripping them into pieces.

#Understanding how vaccines work, 2018


Vaccines which use killed or inactivated germs are called dead or inactivated vaccines. Other types are subunit vaccines, which only use parts of germs.

#Inactivated whole-cell (killed antigen) vaccines, retrieved, 2019


#Subunit vaccines, retrieved 2019


– Live vaccines are the real deal, but we use weak cousins of the germs for them.

#Live attenuated vaccines (LAV), retrieved 2019


In this case a small amount of living, but weakened germs are injected. Since they will put up more of a fight than their cousins – corpses from the dead vaccines– live vaccines trigger more of a immune response which results in more memory cells.

#Principles of Vaccination, 2018


– Some, like the flu virus, mutate so often that we need a new vaccine every year.

#Influenza vaccine viruses and reagents, retrieved 2019


– Vaccines have another aspect: side effects.

#WHO vaccine reaction rates information sheets, 2018


– For example, only 83,000 cases of measles in Europe in 2018.

#Measles in Europe: record number of both sick and immunized, 2019


In this case we talk about the 53 member states of the European WHO region. 2018 the organisation counted 82,596 infected and 72 dead people, children and adults. This is triple the amount of 2017 and the highest number in this decade, continuing a dangerous trend. 2017 globally 110,000 people died, marking the turning point from sinking to rising death numbers, caused by vaccination gaps.


#Measles cases spike globally due to gaps in vaccination coverage, 2018


– The measles vaccine became available in 1963.

#The First Measles Vaccine, 2011



Back then we vaccinated for every disease separately. But thanks to research we were able to create combination vaccines, reducing the number of injections we need for immunisation against many diseases. The most commonly used combination against measles today is MMR, which covers measles, mumps and rubella.

– Estimates say 135 million cases in the 1950s occurred annually.

#Global burden of disease and injury series volume IV, 2004


#Has the 2005 measles mortality reduction goal been achieved? A natural history modelling study, 2007



#Measles, 2018


3-4 million measles cases occurred in the US alone in the 50ies, before the vaccine became available.

– 9,800,000, or 98% will suffer from high fever and a very unpleasant rash.

#Impfgegner und Impfskeptiker, 2004


The best source here was a German paper from the Robert Koch Institute Berlin, which is a federal institute for disease prevention and surveillance. To explain the numbers for our calculations, we used the data from the paper and made an english spreadsheet.

Please note that this translation was not done by a doctor and only serves as clarification for which numbers in the German document we used.

#Comparing risks – measles, 2015


This additional source at least says ‘most children’ will get a fever. For our thought experiment we preferred to use the clear number from the German source above.

– Up to 800,000 of them, or 8% from dangerous diarrhea.

#Complications of Measles, 2018


Diarrhea has such a dangerous effect on children because it causes dehydration. The body loses too much water and minerals to keep up its work, like basic cell functions and detoxification.

– 700,000, or 7%, will suffer from an ear infection.

#Complications of Measles, 2018


The source calls ear infection by its medical name ‘otitis media’, the infection of the middle ear.

– 600,000 kids, or 6%, will suffer from Pneumonia.

#Complications of Measles, 2018


Pneumonia causes 60% of the measles deaths. In our scenario 20,000 children would die, so 12,000 of them would die from pneumonia alone.


Measles, 2018


– Up to 10,000 children or 0.1% will get encephalitis.

#Complications of Measles, 2018



Encephalitis is an inflammation and swelling of the brain. It can cause different symptoms from fever, headache and vomiting to more severe effects like desorientation, impaired vision and speech ability, epileptic fits and unconsciousness. In rare cases, if the disease remains untreated and gets too severe, it can be lethal.

#Severe Measles Infection, 2013



There are other rare complications with measles, for example for pregnant women. Complications in pregnancy are not relevant for our thought experiment, since we talk about children in the video, but maybe interesting to know:

#Complications – Measles, 2018


– 2,500 kids, 0.025% will contract SSPE.

#Subacute Sclerosing Panencephalitis, 2017



This disease is a creeping one. After a measles infection it lingers in the brain and breaks out months or years after the infection. It slowly destroys the patient’s brain. First signs are forgetfulness, problems with sleeping and hallucinations. Later in the process more and more cognitive abilities like moving and speaking are impaired. All patients die from this disease:

#Subacute sclerosing panencephalitis, 2019


#Subacute sclerosing panencephalitis and measles vaccination, 2006



Available data does not suggest that the measles vaccine cause, accelerates the course or trigger SSPE cases.

– Taken together, about 20,000 children will be killed by measles.

#Complications of Measles, 2018



The source gives an estimated death rate in developed countries like the US of 0.2%. In undeveloped countries the mortality is even higher due to the lack of medical infrastructure, war, or famines.


#The Clinical Significance of Measles: A Review, 2004


– The kids who beat measles are left with a severely damaged immune system that needs a lot of time to regenerate.

#Long-term measles-induced immunomodulation increases overall childhood infectious disease mortality, 2015


– MMR Vaccination


MMR is a combination vaccine, which includes the needed serum against measles, mumps and rubella. Over time we developed combination vaccines to reduce the times we need to put needles into our skins.

– Of our 10,000,000 vaccinated kids around ten percent get a fever.

#Information sheet: Observed Rate of vaccine reactions. Measles Mumps and Rubella vaccines, 2014


#Complications of Measles, 2018


– 500,000, or 5% will get a mild rash.

#Information sheet: Observed Rate of vaccine reactions. Measles Mumps and Rubella vaccines, 2014


#Complications of Measles, 2018


– Up to 100, or 0.001% might have a serious allergic reaction and will have to be treated.

#Information sheet: Observed Rate of vaccine reactions. Measles Mumps and Rubella vaccines, 2014



These are the global estimates. In regions with good medical healthcare, like the UK, this number is even lower.


#MMR Vaccine (Measles, Mumps and Rubella Vaccine), 2019


– Up to 10 boys, or 0.0001% might get an inflammation of the genitalia.

#Impfgegner und Impfskeptiker, 2004



This is a conservative estimate. The WHO report suggests that there have been only single case reports, which indicates that the risk is probably lower.


#Information sheet: Observed Rate of vaccine reactions. Measles Mumps and Rubella vaccines, 2014


– And up to 10 kids, or 0.0001% might get the most serious side effect: Encephalitis.

#Information sheet: Observed Rate of vaccine reactions. Measles Mumps and Rubella vaccines, 2014



We talked to different experts and tried to identify such cases in literature. We only found single case reports, so this is a conservative estimate. We go more into detail below the source for ‘documented cases’, the second point below this one.

– Thanks to the good medical treatment in developed regions almost all of them will be fine.

#Risk of anaphylaxis after vaccination in children and adults, 2016



Next to encephalitis anaphylaxis, a life-treathening allergic reaction, is one of the most feared side effects of vaccines. This study, conducted between 2009 and 2011, examined 33 confirmed vaccine-triggered anaphylaxis cases after 25,173,965 different vaccine doses, including MMR. None of the patients died and all of them recovered. Only one unlucky patient out of the 33 had to stay in the hospital, but recovered.

– But in 2019 in it fair to say that vaccines do not cause autism.


One of the most controversial topics around vaccines is the claim that they cause autism. This is such a large field that it would merit a video of its own, but a lot of people have already discussed this topic in detail and explained it very well. But here is a short overview.

The most prominent reason for the autism claim is a study of A. Wakefield from 1998, who claimed that the MMR vaccine that time caused autism. But later his methods and results were debunked as false and the fact that he filed a patent for his own vaccine did lead to the end of his credibility. Other studies took care of the topic and did not find any relations between the vaccine and autism.


#Do Vaccines Cause Autism?, 2019


The most recent example is a large Danish study:

# Measles, Mumps, Rubella Vaccination and Autism: A Nationwide Cohort Study, 2019



The study accompanied more than half a million Danish children over ten years and couldn’t find any increased risk for autism caused by the MMR vaccine.

Another controversial aspect in the debate is Thimerosal, a preservative which is supposed to avoid contamination of the vaccine. It contains mercury compounds, which are often accused of causing autism. But so far there is no scientific evidence that this claim is true. True is that some people might be allergic to it, but thimerosal-free alternatives are on the market.


#Thiomersal - questions and answers, 2011


#A generalized reaction to thimerosal from an influenza vaccine, 2005


– We only could come up with a tiny handful of documented death cases after vaccination.


For our research we tried to find verified reports on death cases caused by the MMR vaccine. While we found sources on encephalitis, we could not identify anaphylaxis cases.

We ended up with between one and nine potential death cases, but what we found does not allow us to give you a number like ‘X people died from vaccines’. We will explain why in the following comments, step by step.

#Adverse Effects of Vaccines: Evidence and Causality, 4: Measles, Mumps, and Rubella Vaccine, 2012



Here we could find one case of encephalitis death. But it is crucial to add that the patient suffered from an impaired immune system. This can be caused by HIV, chemotherapies or old age. People with such deficiencies should not be vaccinated, or only receive dead and subunit vaccines, since their immune soldiers are not strong enough to deal with the live germs. We could not find a verified case where a healthy person died from vaccine induced encephalitis.

#Acute encephalopathy followed by permanent brain injury or death associated with further attenuated measles vaccines: a review of claims submitted to the National Vaccine Injury Compensation Program, 1998



Here we have a very difficult case. In this source there are 8 deaths described. But by reading the source carefully, we found a few problems that are important to keep in mind. Let’s have a look:

In this rather old study many different vaccines cases were examined, dating back to the 70ies. It is not described whether the dead children received MMR or one of the other vaccines, so we can’t link the deaths to one specific vaccine. And the second and bigger problem is that the source states that all encephalitis deaths with unknown cause within 15 days after vaccination were linked to vaccines. That is a bold claim, since no follow up examinations to proof this are described here. Also it is not clear if the children had other health issues before, which could have played a crucial part in their death.

Also the reports are taken from a compensation program. This means people report problems they had with vaccine side effects and demand financial compensation for their injury or pain. In this short source it is super hard to determine whether these reports were scientifically verified, so we don’t even know if the claims that the deaths were caused by vaccines are true. So it is not possible to determine if any of the eight deaths was really caused by MMR or one of the other vaccines.

– Children received the MMR vaccine since 1971.

#Q&As about Monovalent M-M-R Vaccines, 2019


– In 2017 alone 110,000 people died of measles worldwide.

#Measles, 2018


– This is called herd immunity.

#Vaccination, 2018


– The immunisation rate has to pass a threshold. 95%.

#Vaccination, 2018



It is important not to mix immunity level and vaccination coverage. Vaccinations are 99% effective, but this number can be lowered if the basic immunisation is not completed, meaning not all necessary doses given, or if in certain cases immunity is not obtained. This sometimes happens due to genetic reasons and other vaccines must be applied. So the vaccination rate is always a bit higher than the percentage of people immune to the disease.

Further reading:

– FAQ for MMR vaccination.


#MMR vaccine FAQs, 2018


– Who invented vaccines?

#Chinese Smallpox Inoculation, retreived 2019


#Science and Civilisation in China: Volume 6, Biology and Biological Technology, Part 6, Medicine, 2000, S. 152


– Sometimes we inject extra substances, to provoke the body to make even more memory cells: adjuvants.

#Adjuvants help vaccines work better, 2018


#Vaccine ingredients, 2019



Since dead and ripped enemies are not a huge threat for a healthy immune system, our immune response is not as huge as it would be if it encountered live germs. So sometimes adjuvants are added to vaccines to trigger a larger immune response and to get more memory cells out of the fake attack we mimic with the dead and subunit vaccines.

– Other vaccines and their side effects.


Other vaccines like DTP, a combination against diphtheria, tetanus (lockjaw) and pertussis (whooping cough), come with different side effects. To cover all of them we would have been forced to make an hour-long documentary. So we decided to focus on the MMR vaccine, since measles is one of the most contagious diseases and MMR one of the most commonly used vaccines against it. For the side effects of other vaccines you can find the sheets here:

#WHO vaccine reaction rates information sheets, 2018


– An person infected with measles will infect up to 90% of the people around them that are not immune.

#Transmission of Measles, 2018


– We talked about measles. But what are rubella and mumps?

#Rubella, 2018


#Mumps, 2018



Mumps is not thought to cause infertility in the sense of sterility. But it influences the production of sperm cells negatively, making it hard to have children.


#Mumps. For Healthcare Providers, 2019


– No adequate relationship between meningitis and MMR.


In some older sources meningitis, a swelling of the brain, is listed as a severe side effect of the MMR vaccination. But in the last years the relation between meningitis and MMR vaccine was disproven:

#4: Adverse Effects of Vaccines: Evidence and Causality, 2011


#Risks of Convulsion and Aseptic Meningitis following Measles-Mumps-Rubella Vaccination in the United Kingdom, 2007


– There are databases for self reported side effects. But they are mainly not verified.

#Guide to Interpreting VAERS Data, retrieved 2019



VAERS is a reporting system where any person can report side effects. Only a tiny fraction of them is scientifically verified, so reports of side effects from there are not the best way to educate yourself about side effects.

– A study from 2017 could only identify 6 relevant reports of lethal anaphylaxis.

#Vaccination and anaphylaxis: a forensic perspective, 2017



In this report scientists address an important problem: the risk of anaphylaxis, a life-threatening allergic reaction. Reports of anaphylaxis after vaccination might lack the scientific methods of examination to claim that the death was indeed linked to the vaccine. For example in this source 18 reports of lethal anaphylaxis were analyzed, but only 6 were relevant, thanks to sufficient data on the patient. So the number of anaphylaxis death due to vaccination is very low, but to determine a verified number, more medical records about these incidents are needed. None of the deaths was linked to the MMR vaccine we talked about in the video.

– People die shortly after the vaccine, but it wasn’t the vaccine: Background mortality

#Mortality Rates and Cause-of-Death Patterns in a Vaccinated Population, 2013


– What are febrile seizures?


If the fever gets too high, some children might react with febrile seizures. They show in twitching limbs a stiff body and maybe unconsciousness. This sounds grim, but these seizures usually only last a few minutes and the kid is back to normal within an hour, with no follow up problems. These seizures can be caused by any kind of fever, so both measles fever and the fever side effect of vaccines can cause this common effect.

#Febrile seizures, 2016


#Information sheet: Observed Rate of vaccine reactions. Measles Mumps and Rubella vaccines, 2014


#Measles, Mumps, and Rubella (MMR) Vaccine Safety, 2018


#Febrile Seizures: Risks, Evaluation, and Prognosis, 2012