Updated on 11 April 2025
COVID-19 vaccines work and they are safe.
The EMA video highlights the importance of consulting reliable information sources on COVID-19 vaccination.
This section addresses the most common misunderstandings and false claims about COVID-19 vaccines. The questions are updated regularly to reflect current topics.
There are a lot of incorrect figures about reports of suspected side effects and deaths following COVID-19 vaccination circulating on social media and various websites.
These figures often result from a misunderstanding of how to use the European database of suspected adverse drug reactions.
EMA provides comprehensive information on the safety of COVID-19 vaccines on its website.
To better understand how to use the European database of suspected adverse drug reactions and interpret the data, please refer to the user guide below:
EMA carefully reviews all safety data and can confirm that there is no evidence of an increase in deaths related to COVID-19 vaccination in any age group, including in children.
Data published by Eurostat, the statistical office of the EU, have shown increased numbers of excess deaths in many EU countries over the past years. This largely coincided with waves of increased COVID-19 infections.
The medical literature shows that infection with SARS-CoV-2 can lead to serious health problems, such as heart attack and stroke, even several weeks or months after infection.
Evidence gathered from hundreds of millions of vaccinated people confirms that the safety of COVID-19 vaccines authorised in the EU is very reassuring.
The vast majority of known side effects are mild and short-lived. Serious side effects may occur, but they are very rare.
Reports of deaths following vaccination are also very rare.
During mass vaccination campaigns, it is expected that some deaths will occur shortly after vaccination. This does not mean the vaccine caused the death.
When millions of people are vaccinated, it is likely that some of them will, by chance, experience an illness or even die in the days or weeks following vaccination, without this being caused by the vaccine.
Healthcare professionals should report any death that occurs following vaccination, even if it is unknown if the vaccine was the cause.
In very exceptional cases, deaths have been confirmed to be caused by a vaccine.
For more information, see:
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EMA takes any report of a death following the use of a medicine very seriously. These reports are routinely screened to detect any possible safety issue.
As for other medicines, EMA has received reports of death following COVID-19 vaccination. Between January 2021 and December 2023, with around 1 billion doses of COVID-19 vaccines administered, about 12,000 spontaneous reports of death were received in EudraVigilance from healthcare professionals and members of the public.
This does not mean that COVID-19 vaccines caused these deaths.
When millions of people are vaccinated, it is likely that some of them will, by chance, experience an illness or even die in the days or weeks following vaccination, without this being caused by the vaccine.
In most cases, these events would have happened even if they had not been vaccinated, especially in the elderly and people with pre-existing or undiagnosed medical conditions.
When monitoring the safety of medicines, EMA and EU Member States search the reported suspected side effects for any unusual or unexpected patterns, such as a medical event occurring more often in vaccinated people than in the general population, which may indicate a safety concern.
They also check the data from other sources, such as scientific studies and the medical literature. When a safety concern is detected, EMA and EU Member States investigate this thoroughly and take necessary action to protect public health.
This continuous monitoring has allowed detection of very rare but serious side effects which, in very exceptional circumstances, may have contributed to the death of a vaccinated person.
The vaccines’ product information highlights when a serious side effect could have led to death.
Apart from these very exceptional cases of death potentially linked to serious side effects, there is no evidence so far suggesting that other reported deaths may be linked to vaccination.
For more information, see:
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The main aim of any vaccine is to protect people against a disease.
COVID-19 vaccines are not specifically authorised for preventing virus transmission from one person to another. As with other vaccines, this does not mean they cannot reduce virus transmission or be used with the additional aim of reducing transmission.
At the beginning of the pandemic, regulators asked companies to prioritise studies looking at how well the COVID-19 vaccines protected against the disease. It is difficult to measure how well vaccines may reduce transmission in clinical studies. This can only be done in real-world studies that include large numbers of vaccinated people.
Several studies carried out after their authorisation have shown that COVID-19 vaccines can reduce the transmission of the virus.
The effectiveness of COVID-19 vaccines in preventing transmission varies over time and between countries. These variations depend on the virus strains in circulation and other measures put in place to reduce transmission.
For more information, see:
It is not uncommon for companies to take medicines off the market for commercial reasons, for example, if a product is not widely used.
In the case of COVID-19 vaccines, a company may also withdraw a vaccine if it has no plans to update the vaccine to match the latest circulating strains of the virus.
Withdrawals for commercial reasons are not a major concern if there is no risk of a shortage.
For more information, see:
The COVID-19 vaccines authorised in the EU are regularly updated to help maintain optimal protection against the disease as the SARS-CoV-2 virus continues to change.
When the virus becomes significantly different from the original virus, it is known as a variant. To target virus variants and broaden immunity, the vaccines need to be routinely updated. This helps to keep people protected, especially vulnerable groups.
Marketing authorisation holders update their vaccines based on recommendations issued by EMA, in consultation with the World Health Organization (WHO) and international partners.
For more information, see:
The World Health Organization (WHO) declared the end of the emergency phase of the pandemic in May 2023.
However, the virus continues to circulate in the population.
New virus variants can potentially cause serious disease and even death.
COVID-19 still places a burden on healthcare systems. This happens especially in the winter, when other respiratory viruses like influenza or respiratory syncytial virus also circulate.
In the EU, national authorities in the EU Member States decide who should be offered COVID-19 vaccination and when, taking account of infection rates, hospitalisation rates, risks to vulnerable people, vaccination coverage and other factors.
In the EU, each EU Member State is responsible for vaccination campaigns within its own territory.
Public health authorities in each EU country develop vaccination campaigns based on the spread of the virus and healthcare systemcapacity.
There may continue to be differences between how different EU countries use the COVID-19 vaccines at their disposal.
EMA’s evaluations provide a scientific basis for national vaccination campaigns. They describe the benefit-risk balance of each vaccine in the different populations studied.
The benefits of all authorised COVID-19 vaccines outweigh the risks when used as described in the product information.
COVID-19 vaccination is estimated to have saved millions of lives in the EU and beyond.
Researchers have estimated that the first year of COVID-19 vaccination more than halved the number of deaths due to COVID-19 across the world. This is thought to have avoided between 14 and 20 million deaths.
In May 2022, WHO estimated there were nearly 15 million excess deaths linked to the pandemic in 2020 and 2021 alone.
Widespread vaccination also allowed the lifting of lockdowns and eased the pressure on healthcare systems, by protecting people against severe disease and hospitalisation.
For more information, see:
Infection with SARS-CoV-2 can lead to a wide range of long-term symptoms, referred to as long COVID.
This can also happen in young people.
Symptoms include long-term organ damage, which can even lead to death several weeks or months after the initial acute infection.
Most studies conducted on long COVID suggest that COVID-19 vaccination reduces the chances of experiencing long COVID and potentially the symptoms associated with it.
More information:
A full list of known side effects associated with each COVID-19 vaccine is found in the vaccine's product information.
You can find the product information for all COVID-19 vaccines in all EU languages on EMA’s website.
EMA and the EU Member States continuously monitor reports of suspected side effects with COVID-19 vaccines.This serves to detect any new safety issues.
Suspected side effects are medical events reported after vaccination by a vaccinated person or their healthcare professional. They are collected in the EU database of suspected side effects, EudraVigilance. They are available in a public database, adrreports.eu.
The fact that a medical event was reported as a suspected side effect does not mean that the vaccine caused it.
When assessing the data, EMA and EU Member States look for any unusual or unexpected patterns. These can include medical events occurring more often in vaccinated people than in the general population.
Regulators take into account every single report in EudraVigilance. This is regardless of how much time has passed between receiving the vaccine and the occurrence of the event.
They also consider other sources of evidence, such as studies and the medical literature.
If there is at least a reasonable possibility that a vaccine could have caused a suspected side effect, this is included in the vaccine’s product information.
The product information also indicates the likelihood of the side effect occurring and how to reduce the risk.
For more information, see:
COVID-19 vaccines have been used in hundreds of millions of people around the world and are subject to close safety monitoring.
Long-term safety data on COVID-19 vaccines continue to be very reassuring.
Data are available fromstudies in thousands of volunteers and from mass vaccination campaigns across the world over more than two years.
Moreover, safety monitoring of vaccines shows that any side effect usually occurs within two months of vaccination.
There is no evidence that COVID-19 vaccines may cause side effects, such as cancer, in the long term.
EMA and the EU Member States continue to closely monitor the safety of COVID-19 vaccines in the long term.
Several studies have shown that messenger RNA (mRNA) COVID-19 vaccines do not cause complications in pregnancy, either for expectant mothers or their babies.
On the contrary, COVID-19 vaccines protect expectant mothers and their babies.
The data mainly come from studies with the mRNA vaccines Comirnaty and Spikevax (previously COVID-19 Vaccine Moderna) in more than 65,000 people at various stages of pregnancy.
The studies did not show any sign that the COVID-19 vaccines increased the risk of complications in pregnancy, miscarriage, premature birth or harm to the unborn baby.
The data also confirmed that the vaccines reduced the risk of hospitalisation and death for pregnant people as much as for other people.
Side effects in pregnant people are similar to those in other vaccinated people. They are mostly mild or moderate and resolve within a few days.
More information:
Data from many thousands of people who received an mRNA vaccine while breastfeeding found no risk of side effects in breastfed babies.
Research has found tiny amounts of vaccine mRNA in breast milk during the first 48 hours after vaccination, but not afterwards.
Although more work is needed to understand the relevance of these findings, this amount of mRNA is very small and is not expected to cause any safety problem.
There is also evidence that breastfeeding people who received an mRNA vaccine have antibodies against the SARS-CoV-2 virus in their breastmilk. This may help to protect their baby against infection.
More information:
COVID-19 vaccines are well tolerated in children, based on data from millions of children who have been vaccinated.
The side effects are usually mild or moderate and go away in a few days, based on real-world evidence and clinical trials in children.
Very rare cases of myocarditis and pericarditis (inflammatory conditions affecting the heart) have occurred in adolescents and adults after vaccination with certain COVID-19 vaccines. This risk is much lower in children aged 5 to 11 years.
These conditions usually clear up following treatment, as they do when unrelated to vaccination (for instance, as a result of a COVID-19 infection).
EMA continues to monitor data on safety in children in the long term.
EMA and the EU Member States continuously monitor the EU database of suspected side effects, EudraVigilance.
EMA has seen no evidence suggesting that some batches of Comirnaty caused any more side effects or more serious side effects than other batches of the vaccine.
Official Medicines Control Laboratories (OMCL) in the EU Member States check data on the quality of every batch of COVID-19 vaccines before it is released for use in the EU. Only batches that comply with EMA’s approved quality specifications can be used in the EU.
For more about how side effects are monitored, refer to the 'Vaccine safety' section on this page.
The technology used to develop the mRNA COVID-19 vaccines had already been extensively studied for some twenty years in the prevention of other infectious diseases and in cancer treatment.
Various mRNA vaccines against diseases such as influenza and Zika had already been tested in the laboratory, animal studies and early clinical trials.
A wealth of scientific knowledge about viruses of the same family as SARS-CoV-2 also helped accelerate vaccine development.
mRNA is a relatively small and simple molecule that is much easier to produce than more traditional vaccines.
This means that producing mRNA vaccines for clinical trials, and then scaling up production for mass vaccination campaigns, was faster than previously possible with other technologies.
More information:
The self-amplifying mRNA technology is another way of using the mRNA platform to develop vaccines and protect people against certain diseases.
As with other mRNA COVID-19 vaccines, the mRNA has instructions for making the SARS-CoV-2 spike protein.
In addition, the self-amplifying mRNA has instructions to make an enzyme called replicase. This generates additional copies of the spike protein mRNA. This means that more copies of the spike protein will be produced.
Kostaive is the first authorised self-amplifying mRNA vaccine for COVID-19. Data on Kostaive indicate that the side effects with this vaccine are comparable to those with existing mRNA vaccines.
Research into self-amplifying mRNA vaccines has been ongoing for well over 20 years.
Much of this research focused on using this technology to treat cancer. Some clinical trials have also studied self-amplifying vaccines against viral infections such as cytomegalovirus and Ebola virus.
Lipid nanoparticles are small fat particles used in mRNA vaccines to help the mRNA enter human cells.
Once the vaccine is injected into the muscle, the lipid nanoparticles fuse with the cell membrane which is also made up of lipids (fats).
This mainly happens in immune cells found around the injection site.
The immune cells that contain the lipid nanoparticles and the mRNA then move to nearby lymph nodes, where they stimulate animmune response.
Lipid nanoparticles are also important in maintaining the quality of the vaccine during storage. For example, this happens by keeping the vaccine stable and making sure the vaccine components work properly.
The use of lipid nanoparticles in medicines has been researched extensively. The first medicine using lipid nanoparticles was authorised in the EU in 2018.
Messenger RNA (mRNA) is a type of molecule that exists naturally in the body and helps make proteins.
The cells in the body translate the information in the mRNA molecule to produce specific proteins.
Like all mRNA molecules, the mRNA in the COVID-19 vaccines is broken down by cell mechanisms. This is why it spends a relatively short time in the body.
Animal studies for Comirnaty used much higher doses of mRNA than included in the final vaccine given to people. These studies found that the mRNA and lipid nanoparticles stayed mainly at the injection siteand lymph nodes. There, they are able to stimulate theimmune response.
In these studies, only small amounts of mRNA were shown to reach other tissues. They are mainly the liver but also the spleen, heart, kidney, lung and brain.
Levels of mRNA decreased over 6 to 9 days after injection.
Animal studies for Spikevax (previously COVID-19 Vaccine Moderna) used an mRNA vaccine that is similar to Spikevax.
The results only detected small amounts of mRNA in tissues beyond the injection site. After 1 to 3 days, the mRNA was found only at the injection site, the lymph nodes and the spleen.
Based on these findings, at the time of authorisation, no build-up of mRNA or lipid nanoparticles in the organs was expected.
For both vaccines, further laboratory studies showed that the spike protein produced from the mRNA can be found in the injected muscle and the lymph nodes. It is also found in the spleen for Spikevax. The protein was not detected in organs such as the lung, heart or brain.
Hundreds of millions of people have used the mRNA COVID-19 vaccines throughout the world. Intensive safety monitoring of COVID-19 vaccines has not detected any safety issue linked to the distribution of these vaccines in the human body.
More information:
The mRNA in Comirnaty and Spikevax is manufactured using plasmid DNA.
Plasmids occur naturally in bacterial cells. They are used as a template to produce the mRNA of the vaccines.
Once the mRNA is produced, the manufacturing process includes steps to break down and remove the plasmid DNA as it is no longer needed.
The plasmid DNA is not intended to be part of the final mRNA vaccines. However, very small amounts of DNA fragments may remain. EMA has seen no evidence linking the residual DNA to side effects.
EMA has set limits for the level of broken-down DNA in mRNA vaccines. The manufacturing process is carefully designed and controlled to ensure safe and acceptable levels.
The quality of every batch of COVID-19 vaccines is checked before it is released for use in the EU. Only batches that comply with EMA’s approved quality specifications can be used in the EU.
EMA is aware that some online reports have claimed that COVID-19 mRNA vaccines contain excessive levels of DNA. This is not the case for any COVID-19 vaccine released by EU authorities for use in the EU.
No batch of vaccine released in the EU had residual DNA exceeding the acceptable levels set.
The mRNA used in COVID-19 vaccines does not interfere with our genetic code. This is because:
Although mRNA can be converted into DNA, this can only be done with a specific enzyme called reverse transcriptase. This is not normally present in human cells, nor is it present in the vaccine.
No side effects linked to gene mutations, such as cancer, have been observed after vaccination with mRNA vaccines.
COVID-19 mRNA vaccines can sometimes contain truncated (shorter) or modified mRNA molecules.
These are considered impurities and are not expected to affect safety or efficacy.
There is no evidence that truncated mRNA is translated into shorter or modified forms of the spike protein.
Human cells have several processes ensuring that proteins are correctly produced and preventing the production of shorter or modified proteins from faulty mRNA.
In the unlikely event that shorter or modified spike proteins were produced, they would not be expected to trigger unwanted immune responses.
Although the risk of producing shorter or modified spike proteins is low, this risk will continue to be monitored as part of the long-term safety monitoring.
A vaccine against an infectious disease is not considered a gene therapy, as it does not aim to restore, correct or modify human genes.
Therefore, mRNA COVID-19 vaccines are not considered gene therapies.
mRNA vaccines are not genetically modified organisms (GMOs) either because they do not contain or consist of an organism.
They are classified and regulated as biotechnology medicinal products.
For more about mRNA vaccines, refer to the video mRNA vaccines: What gets injected into my body?