Human herpesvirus 6 or HHV-6, is a herpes virus just like Epstein-Barr Virus, Cytomegalovirus, Chicken pox (varicella zoster), HHV-7, HHV-8 and Herpes simplex 1 and 2. There are two types of this virus including HHV-6A and HHV-6B. 100% of human beings get infected with HHV-6B by the age of three which results in fever, diarrhea and a rash called roseola. In rare cases it can cause seizures and encephalitis. There are many infection connections to autoimmune diseases like Hashimoto’s disease and in this article I’ll cover the connection between HHV-6 and Hashimoto’s disease.
Less is known about HHV-6A which was found in a small study in 50% of adults. HHV-6A is said to be the most problematic of the two types and it is the type found inside the thyroid glands of some people with Hashimoto’s thyroiditis.
Just like other herpes viruses, HHV-6 can reactivate (occurs in the thyroid gland, GI tract, brain, heart, kidneys, uterus, and lungs) later in life when the immune system is compromised resulting in a variety of conditions including:
Chronic fatigue syndrome
HIV progression to AIDS
Certain types of cancer
Kidney, liver, lung disease
Transplant recipient issues
Bone marrow suppression
What is the link between HHV-6 and Hashimoto’s disease?
Here are some studies supporting the connection between HHV-6 and Hashimoto’s disease:
Rizzo et al. in 2016 found a direct connection among natural killer cell activation, thyroid antibodies, and HHV-6 in patients with Hashimoto’s disease. This study found that the HHV-6 virus causes an increase in natural killer cells against the virus which causes an ongoing inflammatory process in the thyroid gland that correlates with thyroid peroxidase and anti-thyroglobulin antibodies. This means that an active HHV-6 infection in the thyroid gland drives the elevation of thyroid antibodies and increases inflammation in the gland resulting in increased damage to thyroid tissue.
A study published in 2012 entitled “Virologic and Immunologic Evidence Supporting an Association between HHV-6 and Hashimoto’s Thyroiditis” by Caselli et al. found that a high percentage of patients in the study with Hashimoto’s disease have active HHV-6A infections inside the thyroid gland. This increases inflammation in the thyroid gland since the immune system is concerned about Human herpesvirus 6 and due to antibodies against the thyroid gland.
A follow-up study by Caselli et al. in 2017 entitled “HHV-6A in vitro infection of thyrocytes and T cells alters the expression of miRNA associated to autoimmune thyroiditis” also found a connection between HHV-6 and Hashimoto’s disease.
Sultanova et al. in their 2017 paper entitled “Association of active human herpesvirus-6 (HHV-6) infection with autoimmune thyroid gland diseases” found a statistically significant higher level of persistent HHV-6 infection in those with Hashimoto’s disease compared to the control group. They also biopsied thyroid tissue of patients with Hashimoto’s disease compared to a control group without Hashimoto’s disease, and they found a statistically significant higher level of HHV-6 in those with Hashimoto’s disease compared to the control group (18/44 (41%) vs. 1/17 (6%)).
Seyyedi et al. in their 2019 paper entitled “Human herpesvirus 6A active infection in patients with autoimmune Hashimoto’s thyroiditis” consisting of 242 patients found 57 out of 151 (38%) of patients with Hashimoto’s disease had active HHV-6A infections. 5 out of 59 (8%) patients with non-autoimmune thyroid disorders had active HHV-6A infections. And 0 out of 32 (0%) patients with normal thyroid function had active HHV-6A infections.
Why does it reactivate in some people?
For the same reasons that other herpes viruses reactivate in people including physical or emotional trauma, stress, hormone imbalances, other infections, poor diet, gut dysbiosis etc. Herpes viruses are opportunistic when your immune system is compromised so anything that stresses your immune system can cause reactivation.
Reactivation occurs in about 20-25% of the adult population with much more severe symptoms than in infants. Reactivation can create a “mono-like” illness in adults resulting in fatigue, fever, swollen lymph nodes, enlarge liver and spleen, or encephalitis and mental changes.
Human herpesvirus 6 seems to be more drawn to the brain and nervous system resulting mainly in problems associated with these areas of the body. HHV-6 mainly resides in the salivary glands and it is transmitted through saliva from person to person.
What is the best way to test for Human herpesvirus 6?
Testing is tricky with this virus for a few reasons. Antibody tests can “cross-react” with other viruses such as Cytomegalovirus. It is recommended to always test for Cytomegalovirus along with HHV-6 so you can be sure your positive test is accurate and not just a cross-reaction.
IgG antibodies are positive for life but if you see a four-fold increase in these levels then this can indicate reactivation. IgM antibodies will tell you if it is a recent reactivation however these can be elevated even when the virus isn’t active. Additionally, IgM antibodies usually don’t elevate in adults who have reactivation of the virus. If testing for IgG and IgM antibodies, be sure to use IFA testing rather than ELISA.
PCR testing can find the DNA of HHV-6 in the blood to confirm it is present and reactivated. However, this does not rule out infection inside a gland, it only rules out presence in the blood. So it may be active in a gland or body tissue, but not present in the blood. For more detailed information about all the different types of tests check out the HHV-6 Foundations chart.
How is HHV-6 treated?
Conventional medicine doesn’t mention much about treatment other than perhaps trying acyclovir which is used for genital herpes.
Alternative methods are the same for HHV-6 as they are for the other herpes viruses like Epstein-Barr Virus and CMV. Here are the compounds that can work well for all herpes viruses:
As stated in my other articles about treating herpes viruses, simply taking one or a number of these compounds will not yield success in the long run. This is because the underlying reasons for reactivation of the virus must be corrected in order to keep the virus deactivated. This is why you should work with a functional medicine practitioner to fix all the underlying causes of reactivation so that your body can keep the virus at bay for life.
Human herpesvirus 6 and Hashimoto’s disease summary
Testing in adults is useful if you see an increase of IgG levels greater than 4x the normal range which can indicate reactivation. If testing shows that there could be chronic viral activity, then I will target the virus. The treatment for all herpes viruses is the same, so if we are treating the Epstein-Barr Virus, then we will also be targeting HHV-6 for example.
Your functional medicine practitioner will get your body back in balance so your immune system can control HHV-6 and target it if necessary. I get excellent results when we have an infection connection to Hashimoto’s disease such as HHV-6.