This page contains information about the side-effects of the COVID-19 vaccines made by Pfizer/BioNTech, Moderna, AstraZeneca and Janssen. 

Most common side-effects of the COVID-19 vaccines

Side-effects such as fever, headache and tiredness occur after vaccination with COVID-19 vaccines in a significant proportion of those who are vaccinated. Side-effects such as muscle pain, joint pain, chills, nausea and vomiting may also occur after vaccination with COVID-19 vaccines. These symptoms start within a day or so after vaccination and go away by themselves, but can be unpleasant.

For a complete overview of the possible side-effects, see the vaccine package leaflets.

Very rare and serious side-effect of Janssen and AstraZeneca vaccines

In very rare cases, more serious side-effects may also occur. These symptoms are very uncommon. In the context of the AstraZeneca and Janssen vaccines, this can involve a combination of blood clots (thrombosis) with low levels of blood platelets (thrombocytopenia). This side-effect is referred to as thrombosis with thrombocytopenia syndrome (TTS).

Since the risk of this rare side-effect is very low, these vaccines are deployed for some specific groups. The AstraZeneca vaccine is only given to people born in 1960 or before. On 2 June, the Health Council of the Netherlands advised using the Janssen vaccine in situations in which the advantage of a single vaccination (rather than 2 doses) is very significant. Another relevant factor here is that mRNA vaccines are now available in sufficient quantities and the oldest age groups have already been vaccinated. Read more in the advisory report (in Dutch).

It is important to contact medical professionals immediately if you develop these symptoms after vaccination with Janssen or AstraZeneca:

  • shortness of breath;
  • pain in the chest or abdomen;
  • swelling or a cold feeling in an arm or leg;
  • severe or worsening headache or blurred vision;
  • persistent bruising;
  • multiple tiny blood spots: red or purple dots or blisters under the skin.

If these symptoms do occur, they are usually seen within three weeks after vaccination.

More information is available on the page about AstraZeneca side-effects. The website of the Dutch Medicines Agency (CBG-MEB) also offers more information about AstraZeneca and Janssen (in Dutch).

Myocarditis and pericarditis

Reports have been received of myocarditis and pericarditis following COVID-19 vaccination. Both of these are inflammatory diseases of the heart: myocarditis is inflammation of the heart muscle, while pericarditis is inflammation of the outer lining of the heart. The European Medicines Agency (EMA) is assessing these reports.

Cases have been reported in various countries, including Israel and the USA. The reported cases in Israel mainly affected males under 30 years of age who had been vaccinated with the Pfizer vaccine. 24 cases have been reported in the Netherlands so far. They are still being assessed by Pharmacovigilance Centre Lareb. The reported cases in this country involve men and women of various ages, and not only after vaccination with the Pfizer vaccine.

The reports indicate that myocarditis and pericarditis mostly started within the first four days after vaccination, and were more likely to occur after the second vaccination than after the first. Symptoms are comparable to other heart conditions, with chest pain being reported most frequently. Other symptoms may include shortness of breath and a forceful heartbeat that may sometimes be irregular. The symptoms can vary significantly and usually improve on their own or can be treated effectively with medication. People who have these symptoms should consult their doctor. Referral to a cardiologist for further diagnostic tests and exclusion of other causes may be necessary.

Myocarditis and pericarditis are not currently listed in the package leaflets as possible side-effects. That will not take place unless it has been officially confirmed that these conditions have a causal relationship with the vaccination.

The incidence of myocarditis and pericarditis ranges between 1 and 10 in 100,000 people per year. In Israel, the incidence of reported cases after vaccination was approximately 1 in 3000 to 1 in 6000. The inflammatory conditions can occur following an infection or immune disease and usually improve on their own.

A review of seven cases is presented in this preprint.

Allergies

If you know that you are allergic to one or more of the ingredients in the vaccine, then you should not be vaccinated. Also, if you had a severe allergic reaction after the first vaccination (and it was probably caused by the vaccination), you should not receive the second vaccination. 

It is possible for a severe allergic reaction (anaphylactic shock) to occur immediately after vaccination. The vaccine has been administered to many, many people all over the world now, and anaphylactic shock appears to be very rare. If you have ever had a severe allergic reaction or breathing problems after a vaccination, always report this to the doctor at the vaccination site. After vaccination, everyone will remain at the vaccination site for 15 minutes longer so that any allergic reactions can be treated immediately.  

Trial dose possible?

You cannot receive a trial dose of the vaccines.  However, everyone who receives a vaccine is monitored for 15 minutes after vaccination. If an allergic reaction does occur, it can be treated immediately.

Medications for side-effects

You can take paracetamol to relieve the symptoms. Do not take more than the amount stated in the paracetamol package leaflet. If you are concerned even so, you can contact your family doctor.

Fever after vaccination against COVID-19

If you develop a fever within 48 hours after receiving the vaccination, it is likely that the fever is a side-effect of the vaccination. In that case, it is best to stay home yourself, but your household members do not have to stay home. If you have a fever, but also have other symptoms that could indicate COVID-19, such as cold symptoms, coughing, or sudden loss of smell or taste, make an appointment to get tested. Except for the test, you must stay home, and your household members must also stay home until you get the results of the test. In case of doubt, you can consult the GGD infectious disease control department. If you develop a fever more than 48 hours after vaccination, you may have a coronavirus infection. In that case, get tested; you and your household members must stay home until you get the results of the test.

Death after vaccination

If someone dies after a vaccination, the death is reported to Lareb. An investigation then takes place to determine the cause and whether there is a direct link between the vaccination, any possible side-effects and the person’s death. A few deaths have been reported in the Netherlands that occurred after COVID-19 vaccination. The European Medicines Agency (EMA) monitors reports of side-effects and deaths from all countries. The EMA publishes a monthly report on these figures. 

Everyone in the Netherlands over the age of 18 will be offered a COVID-19 vaccination. That includes elderly people and people in (extremely) vulnerable health. Vaccination of vulnerable elderly people started on 18 January. An estimated two thousand people aged 80 years and older die each week in the Netherlands on average. These deaths will also include people who have recently been vaccinated. 

You can report side-effects of the COVID-19 vaccine to the Pharmacovigilance Centre Lareb.

Study on side-effects of COVID-19 vaccination

As of 1 February, the Pharmacovigilance Centre Lareb has started actively monitoring side-effects after COVID-19 vaccination. In this study, vaccinated people will be sent 7 questionnaires over a period of 6 months. This will provide more information about which side-effects occur, how often they occur and how they develop. People can sign up for this study within 48 hours of their first COVID-19 vaccination or after making an appointment to get their first vaccination. For more information about the study (in Dutch), go to: www.mijncoronavaccin.nl.