Your Resource for all Things Relating to Factor V Leiden

Volume 1/ Issue 2 / May, 2021

In This Issue…


  • “COVID-19 Vaccines and Factor V Leiden – What We Know So Far” – a look at what the medical community is telling those with FVL concerning COVID-19 and the COVID-19 vaccines.

  • “Your Voice was Heard… Fulfilling a Need and Desire For Knowledge” – a message from Executive Director Dr. Teresa Ousley.

  • Factor V Leiden Follow-Up – Thank you for your positive feedback and kind words about the new website. As the AFVLA enters its second year, there is a lot of work still to be done to get the word out

Welcome to the 2nd Issue!


Emailed each month, this newsletter will cover the latest topics of interest making the news, keep you informed about current research studies, and offer noteworthy and relevant stories from our staff, medical professionals, and others interested in or affected by Factor V Leiden. In it you will find informative articles explaining what your association is doing to promote awareness and to educate others about Factor V Leiden. You will keep up-to-date on the latest initiatives being carried out by the association and explain how we are advocating for you to help keep you and your family safe.



Our goal is to make it interesting, informative and usable as a tool to pass along and convey to others important and relevant information about this very common genetic blood clotting disorder.

Thank you so much for your interest and support… we are so grateful and very much depend on caring people like you to help spread the word about Factor V Leiden.

Factor V Leiden Headlines

COVID-19 Vaccines and Factor V Leiden – What We Know So Far


Log on to any Factor V Leiden (FVL) support page and you will see question after question asking, “I am heterozygous for FVL… are the vaccines safe?” or “I have FVL plus other inherited or acquired conditions… which vaccine should I get?” It is safe to assume that questions like these are on the minds of most people who know they carry the FVL gene. Although new headlines seem to appear every day addressing safety concerns, very few studies address Factor V Leiden and its interaction, if any, with the vaccines.


Concerns about blood clots appeared early on with the AstraZenica vaccine in Europe. The pausing of the Johnson and Johnson vaccine on April 13 due to six cases of the rare blood clot known as a cerebral venous sinus thrombosis (CVST) alarmed many, especially those with FVL. Sadly, many in the FVL community are very familiar with the acronym CVST. The pause has since been lifted by the CDC and the J&J vaccine is again being used.


The AFVLA began researching this topic and found only a handful of studies that briefly touch on FVL and the vaccines. As you can guess, information is very limited at least for now.


Blood Clots and the COVID-19 Infection


First, as a reminder, it became known and was well published early on at the onset of the pandemic that becoming infected with the COVID-19 virus caused an increase risk for blood clots. If you become infected with the COVID-19 virus, it is very important to let your doctor know you are FVL positive.


Blood Clots and the COVID-19 Vaccines


As we mentioned, although new information is continuously being published, our research found very little information available that pertains exclusively to heterozygous or homozygous Factor V Leiden (FVL) carriers and the COVID-19 vaccines as of this writing.


An in-depth search of the Centers for Disease Control and Prevention (CDC) website did not find any information specific to FVL and the vaccines.


The National Blood Clot Alliance (NBCA), a prominent and well respected health organization dedicated to advancing the prevention, early diagnosis and successful treatment of life-threatening blood clots, state that they do not have any specific information about the vaccines and Factor V Leiden as of this writing.


A webinar released on April 22 by the North American Thrombosis Forum (NATF) and the University of North Carolina College of Medicine briefly touches on Factor V Leiden and other inherited thrombophilia. It suggests that FVL does not play a role in the development of the blood clots associated with the J&J vaccine. You can review the information below.


Watch the Webinar


The webinar also addresses those people who are currently on anticoagulants (blood thinners) and offers information about receiving the vaccines.

On April 23, the NATF released the following position statement:

The North American Thrombosis Forum (NATF) strongly recommends that all adults get vaccinated against COVID-19, including:

  • People who have had a blood clot in the past
  • People with genetic clotting disorders (such as factor V Leiden) or who have a family history of blood clots
  • People who take anticoagulation (sometimes called blood thinners)
  • People who take antiplatelet medications (aspirin, clopidogrel, ticagrelor)
  • People who have bleeding disorders such as hemophilias

The NATF position statement went on to say that “Vaccination is the key to protecting our individual health and limiting the spread of COVID-19 in our communities. It’s also the best tool we have to prevent blood clots and other vascular complications associated with COVID-19, such as pulmonary embolism (PE), deep vein thrombosis (DVT), and stroke, as well as the chronic symptoms, called “COVID long-haulers syndrome,” which can persist indefinitely and be debilitating.”


The position statement added a Disclaimer that “this position statement reflects the consensus of the NATF Board of Directors and Medical Advisory Board and is based on the best available evidence. It is provided for informational purposes only and is not intended to serve as personalized medical advice. If you have specific questions or concerns about the vaccine, please consult your personal physician or healthcare provider. NATF does not endorse or recommend one vaccine over another, nor do we endorse any one vaccine manufacturer and/or the products they distribute.”


Another case study that mentions FVL was published by King’s College in London on April 8. A male age 25 who was heterozygous Factor V Leiden positive received the AstraZenica vaccine (which is not available in the United States) and six days later developed a cerebral venous sinus thrombosis and passed away. However, the medical providers in his case do not believe that Factor V Leiden played any role in the blood clots as there were other issues in conjunction with the vaccine they feel contributed to the clots.


With the AstraZenica vaccine, authorities report that they are seeing blood clotting around the brain and abdomen accompanied by low counts of blood platelets. They state that this is an unusual combination because platelets typically help the body blood clot in a good way to stop bleeding. Usually high platelet counts and severe clotting go together, not low blood platelet counts.


As we mentioned, our research did not find any study that focuses exclusively on Factor V Leiden and the COVID-19 vaccines. If you have found relevant studies that address FVL and the vaccines, please pass that information along to us at We are all in this together and knowledge is power.


We understand the strong need and desire to want to know more and to have answers concerning the vaccines and FVL. It is very frustrating when an association like ours whose mission is to provide you with information is unable to do so simply because there isn’t any reliable and fully authoritative information available.


Our first concern is your health and safety and that of your family. The AFVLA is not comfortable making a recommendation about someone with Factor V Leiden getting or not getting the vaccine without first obtaining definitive findings and results from peer-reviewed, authoritative studies that focus exclusively on Factor V Leiden. Your trust and confidence is just too important to us.


We know that everyone’s situation is different and other medical conditions may be present. We are not doctors and do not claim to offer medical advise.


The AFVLA encourages everyone with FVL to discuss the risks and benefits of the COVID-19 vaccine, along with all of their medical concerns, with their healthcare provider. 


The American Factor V Leiden Association will continue to monitor the situation and issue more information as more is known. We will send notifications to all subscribers if new findings surface that you need to know right away.


Please know that the association is working hard to keep up-to-date and striving to keep you and your family safe. Thank you for your patience and your confidence.

Factor V Leiden >>Fast Fact<<

Factor V Leiden is an inherited genetic disorder meaning that you inherited it from one or possibly both of your parents and thus, you were born with it.

Factor V Leiden Office Memo

Your Voice was Heard… Fulfilling a Need and Desire For Knowledge

You have probably seen the numbers… the Centers for Disease Control and Prevention estimates that 900,000 people each year suffer from a venous blood clot just in the United States. They go on to estimate that approximately 100,000 people will die, usually due to a pulmonary embolism (PE) or blood clot that has traveled to one or both of the lungs. Sadly, one in four of these deaths occur without warning. The CDC also estimates that 3 in 10 people who have had a blood clot will have another episode within 10 years.



Venous thrombosis (or blood clots) has become one of the leading causes of cardiovascular death in the country and the leading cause for preventable hospital deaths. Blood clots are a leading cause of death in people with cancer after the cancer itself. PE is a leading cause of death in a woman during pregnancy or just after having a baby.



How much of a role does Factor V Leiden play?


Studies vary but it is estimated that around 30% of the people who present at a medical facility with a first time venous blood clot carry the Factor V Leiden mutation. This number increases to a staggering 60% to 70% for those people returning with a second or third recurring venous blood clot.


The medical community believes that in many of these occurrences, the thrombosis is “triggered” by another risk factor or catalyst such as surgery, immobility, pregnancy, smoking, cancer, etc. Medical professionals feel that it is these triggers, in conjunction with Factor V Leiden, that cause many of the venous blood clots to form.



The Need to Know


Many people who suffer a recurrent venous blood clot were not tested for Factor V Leiden (FVL) when they had their first venous blood clot.

When people do test positive, most have never heard of FVL.


Many people die never knowing they carried the FVL mutation.


If the person had known they carried the Factor V Leiden gene mutation, their increased awareness of their risk for blood clots combined with some simple lifestyle changes may have saved their life in many cases. Visit our website to learn more.


There is a great need for people to know if they carry the Factor V Leiden genetic mutation and to know about the increased risks for venous blood clots associated with FVL.



The Desire to Know


A recent consumer experience study published in September, 2020, showed that over 80% of individuals who have tested positive for Factor V Leiden are satisfied with knowing that they have the gene mutation and over 77% feel that they have an advantage in knowing their genetic probability for developing a venous blood clot. Over 85% stated that they felt they could take steps to reduce their risk and many talked to their family members about the results. Over 95% stated that if they could do it all over again, they would choose to learn about their genetic risk for a VTE.


The public is receptive to being tested for Factor V Leiden and has a desire to know more about this disorder.




Your Voice Heard…


Sadly, the number of cases of venous thrombosis are significant numbers. But we know this is not about the numbers… the numbers represent real people like you and me living their lives, loving and providing for their families, and wanting to see their kids live long, happy and healthy lives. The AFVLA strives to never lose that focus… we are about people like you.


The AFVLA is about you and your voice and your right to know about the things that affect your health.


Thus, our mission is to encourage testing and to give you the latest information and best resources available to help you and your healthcare professional make informed decisions about your health and the health of your family and loved ones.

The AFVLA will work to make sure your voice continues to be heard both by us and by those who can make a difference in your health.


If you have a passion for Factor V Leiden and would like to help us educate others, please consider partnering with us as we work to help save lives.

Factor V Leiden >>Fast Fact<<

Another name used for Factor V Leiden is Activated Protein C Resistance.

Factor V Leiden Follow-Up

A big thank you to everyone who expressed their appreciation and positive feedback toward the new AFVLA website and newsletter. Your kind comments and support were very much appreciated. The association would not be able to carry out its mission and objectives without caring and generous people like you who have a heart to help. Thank you.


On June 22 the American Factor V Leiden Association will celebrate its first year anniversary. A lot has been accomplished over the last year but there is a tremendous amount of work ahead. The staff at AFVLA is excited about the future and ready to take on the challenges.

In the coming year plans are to…


  • Complete and further expand the online Factor V Leiden Research and Resource Library to give you the information you need in one place.
  • Issue Position Statements on testing guidelines and other important issues to better protect you and your family.
  • Create a YouTube channel and produce several educational and informative videos to keep you up-to-date on current topics relating to FVL.
  • Continue the objective of increasing public awareness and promoting education about Factor V Leiden through all means available.

Please continue to spread the word about Factor V Leiden. Something as simple as talking to your neighbor or to someone you know who has had a blood clot can make a difference. Mentioning FVL to someone starting birth control or hormone treatments with estrogen could even save a life.

Factor V Leiden >>Fast Fact<<

Factor V Leiden was first identified at Leiden University in Leiden, a city in the Netherlands by Dr. Rogier M. Bertina and Dr. Pieter Reitsma, PhD in 1994.

Introducing the American Factor V Leiden Association Facebook page!

Here is where you can find the latest news and information about Factor V Leiden posted by the AFVLA. You can see the status of upcoming events and stay up-to-date with what is happening at the association. You can also share your thoughts and ideas with us and others. Click below to check it out!

In the June, 2021 Issue...

  • Monthly Features:

    Factor V Leiden Headlines –

    • “Who Should Be Tested For Factor V Leiden – The Controversy Continues” – the controversy and debate over testing for FVL and what you should know.

    • “COVID-19 Vaccines and FVL Update” – we will continue to research the COVID-19 vaccines and keep you updated on any findings. An interim newsletter will be emailed if new information arises that you need to know.

    Factor V Leiden Office Memo – Some thoughts from our Executive Director Dr. Teresa Ousley.

    Factor V Leiden Fast Facts – Fun facts that expand awareness and promote education about this barely known but very common genetic blood clotting disorder.

    Factor V Leiden Follow-Up – We address your questions and comments from previous issues. Your voice is very important to us.

Our Mission...

The American Factor V Leiden Association is dedicated to its mission to serve as a central resource to the general public and medical community, expand awareness, promote education, advocate for and support those affected, assist in establishing testing guidelines, strongly encourage additional research, and facilitate in the exchange of information relating to Factor V Leiden. The ultimate goal is to save lives that would be lost to thrombosis related to Factor V Leiden.

Meet Dr. Teresa Ousley…

Dr. Teresa Ousley is a co-founder of the American Factor V Leiden Association and serves as the Executive Director. Her always positive, happy demeanor, dedication, and absolute concern and caring for others perfectly models the desired image, purpose and goals of the organization. Her Doctor of Nursing Practice degree with an emphasis in leadership was preceded by a Master of Science in nursing education. She has spent several years educating our future nurses of tomorrow and continues to serve as an Assistant Professor of Nursing. Her true passion and dedication for education and public awareness shines through the moment you meet her. The association is very blessed to have her at the helm forging its future and being laser focused on accomplishing its mission. Take a second and say “hi”, she has never met a stranger and would love to hear from you.

Please visit

Get involved and make a difference!

Together through knowledge and awareness we can reduce the risk and help to improve and save lives.

The American Factor V Leiden Association, Inc is a non-profit 501(c)(3) charitable organization. Your gift regardless of the amount goes a long way to further the cause and help get the word out about this barely known but very common genetic blood clotting disorder.

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