This week has started with the large-scale vaccination against COVID-19, the disease caused by the coronavirus. In addition to Community – the vaccine from BioNtech/Pfizer – the second vaccine, from Moderna, has also been approved. Can you also use this corona vaccine if you use anticoagulant drugs?
In the Netherlands, no fewer than 2 million people use anticoagulants, also known as blood thinners, every year. These drugs – called anticoagulants in official terms – reduce or slow the clotting of the blood. They actually restore the balance: the blood should neither clot too much nor too little, because then unwanted bleeding can occur. Although the name blood thinners suggest otherwise, your blood does not literally become thinner, it just clots less quickly.
Doctors prescribe anticoagulant drugs for unwanted clots or at risk of them:
- In (unstable) angina pectoris
- After a heart attack
- After a TIA or a stroke
- In atrial fibrillation
- In case of thrombosis (leg) or display lesbian
- In case of pulmonary embolism
- After placing an artificial valve
- With bedridden people
When you take blood thinners, it is better to avoid medicines such as anti-inflammatory drugs (ibuprofen, diclofenac), certain antidepressants, and other blood thinners (such as aspirin). The main side effect of anticoagulants is an increased risk of bleeding. But what about the vaccines against COVID-19? Can you be vaccinated safely if you are taking blood thinners? The answer is ‘yes, but there are some caveats.
Both the biotech/Pfizer vaccine and the Moderna vaccine are so-called mRNA vaccines. It introduces very small fat globules into the body with a piece of genetic code (mRNA) such as is present in the coronavirus. This mRNA is converted in the body into spike proteins, a protein of the virus. The pieces of this protein thus become visible to the immune cells in the body, which then produce antibodies that recognize the virus when infected. If someone comes into contact with the coronavirus in the future, they will be killed. The vaccine is broken down naturally by the body.
Contact your doctor
Like many other vaccinations, the corona vaccines are placed in a muscle in the upper arm. We call that intramuscular injection. This can lead to bleeding or bruising. If you use anticoagulant medication, the risk of bleeding is already slightly higher. It is therefore important that you contact your GP or the thrombosis service as soon as the call for vaccination has arrived. The same applies if you have a disease that makes your blood clot less well, such as Factor V Leiden, Von Willebrand’s disease, hemophilia, immune thrombocytopenia (ITP), or thrombotic thrombocytopenic purpura (TTP).
What precautions can you take?
The doctor or nurse can tell you before vaccination whether vaccination is possible, or whether precautions may need to be taken. Usually, you can be vaccinated, but sometimes the time of vaccination is important or it is better to vaccinate at a different place.
Do you take Vitamin K antagonists?
As mentioned before, blood thinners ensure that the blood does not clot too quickly or too slowly. The value within which these coagulation results must lie are called the target values and are expressed in INR (International Normalized Ratio). When using coumarin derivatives, such as acenocoumarol or phenprocoumon (also called Vit.K antagonists or VKAs), your INR must be within target ranges or below to receive the vaccination.
Do you take DOACs?
If you use direct-acting anticoagulant medication (DOAC), the timing of the vaccination in relation to the intake of the medication is important, because the peak level is reached 3-4 hours after taking the medication. In practice, this means that with a once-daily intake of DOACs such as rivaroxaban or edoxaban, there is preferably a minimum of 12 hours between the last intake of the DOAC tablet and the moment of vaccination. When taking DOACs twice a day, such as apixaban or dabigatran, it is preferable to vaccinate just before taking the next tablet. If this is not practically feasible, it is preferable to administer the vaccine at least 4 hours after the last ingestion. After the vaccination, the injection site in people who have DOAC’
In all cases, the following applies: if your practitioner advises against intramuscular vaccination, you cannot be vaccinated with the COVID-19 vaccine. But that is not expected to happen much.