Most people probably do not think about blood clots regularly. But with reports of a small number of people developing blood clots after receiving the Johnson & Johnson or the AstraZeneca COVID-19 vaccine, many people are now wondering what the warning signs are.
There are different variations of blood clots, each with its own set of red flags and treatment options. It can be formed for several reasons, including medication, lifestyle factors and other health conditions, and it can occur in different parts of the body.
That being said, blood clots can cause serious damage or be fatal if left untreated. If you’ve worried – whether it’s because of a vaccine or, probably, something else – read on for the signs to look out for, and advice on what to do if you think you’re at risk.
Symptoms of blood clots
Blood clots can form in the veins or veins. There are two main types of blood clots to look out for, and each can lead to its own set of potential complications. One type is called a thrombus, which is a stationary clot. It blocks blood flow in the part of the body where the clot occurs. Another type, called an embolus, is a blood clot that can break loose. It is especially dangerous because it can move to other parts of the body, such as the heart or lungs, and cause serious damage.
The symptoms of blood clots vary depending on the type. When the blood clot stops, such as deep vein thrombosis (a clot in your leg), you may experience:
- Heat and redness where the clot is – usually in the leg or in the arm
- Swelling
- Pain near the site of the clot
- Numbness or weakness
- A change in your state of mind
If the blood clot has traveled, leading to complications such as a pulmonary embolism (a clot that has moved to your lungs), you may experience symptoms, including:
- Sudden shortness of breath
- A cough, with or without blood
- Damp, pale or blue skin
- Excessive sweating
- Anxiety
- Weakness
- Nausea or vomiting
Blood clots can affect your arms, legs, heart, lungs, kidneys and brain, depending on where they form and where they move in the bloodstream.
A handful of people who received the Johnson & Johnson vaccine developed complications due to a blood clot that formed in the veins near the brain called cerebral venous sinus thrombosis, or CVST. This problem is seen in combination with low levels of platelets. (A few people who received the AstraZeneca shot experienced blood clotting caused by the same problem, but since the dose of AstraZeneca has not yet been approved for use in the United States, this story will focus on J&J.)
According to the Centers for Disease Control and Prevention and the Food and Drug Administration, the symptoms associated with this form of complication such as headache, abdominal pain, leg pain or shortness of breath are within three weeks of vaccination.
A few important remarks about the J&J vaccine: Blood clots after the shot appear to be extremely rare – as of now there are only six cases of almost 7 million doses of the vaccine being distributed – and it has occurred within 13 days and vaccination. You have a higher risk of developing blood clots due to a real COVID-19 infection.
“Just remember that COVID-19 causes blood clots,” Amesh Adalja, an infectious disease expert, told HuffPost in a separate story. “And COVID-19 causes higher blood clots than the vaccine does.”
Experts stress that the vaccine could be a game changer for the pandemic, and a major reason for the disruption in distribution is to inform healthcare providers how to detect, treat and report the problem. Do not let this stop you from getting any vaccine against the coronavirus.
What to do if you suspect you may have a blood clot – and how to prevent it
First and foremost, you should seek immediate medical attention. Blood clots can be serious or fatal, so if you suspect you have one, it is important that you address it. If in doubt, call 911 or go to the emergency room – especially if you have the above symptoms, along with chest pain or breathing problems.
Once you are with a healthcare provider, you should notify them of any history of medical conditions, medications or recent vaccinations. This is especially important if you have just received the Johnson & Johnson COVID-19 vaccine, as the treatment for the specific clotting problem is different from what doctors normally do to treat blood clots.
Talk to your doctor for a long time about reducing your overall risk of blood clots. Also let them know of any family history of the case.
Certain lifestyle factors can increase your chances of blood clots. For example, if you are inactive or immobile for a long time – such as during a long flight or during bed rest – it can contribute. Smoking and obesity can also increase your risk.
Medications such as contraceptives and some HIV treatments cite blood clots as a possible side effect. According to the American Heart Association, conditions such as autoimmune disorders, pregnancy and cancer are also associated with clotting.
If you are traveling or in a situation where you will be immobile for a long period of time, you should exercise, stretch and move your legs regularly to improve blood flow – especially in your calves. You can also benefit from wearing compression socks. For other prevention methods, talk to your doctor. Depending on your health history and current diagnoses, your doctor may suggest certain treatment options that may help you address any of these possible complications. This can include a plan for diet, exercise, medication or all of the above.
If you suspect you have a blood clot, do not delay. It is better to address what appears to be nothing than to ignore what appears to be something. And it’s worth it to be vigilant about your health.