I recently read, for the million-teenth time, that anyone who carries MTHFR variants should not be vaccinated. The reason given is that those with decreased MTHFR enzyme activity cannot detoxify or ‘handle’ vaccinations.
This article reviews the published scientific studies on the topic of MTHFR and vaccinations. I am not weighing in on whether you should vaccinate your children. I advocate for learning about all health topics and making decisions based on scientific evidence.
MTHFR Genetic Variants:
The MTHFR gene codes for the enzyme that plays a critical role in using folate in the methylation cycle. There are two genetic variants of MTHFR that many researchers have focused on. These two variants are known as C677T and A1298C. (Read more and check your 23andMe data here: How to check your genetic data for MTHFR.)
I purposefully refer to the genetic change in MTHFR as a variant instead of a mutation. At least one copy of the C677T variant is found in over half the people in most population groups. This is not a rare mutation.
Studies on MTHFR and vaccine injuries:
Researching the studies on MTHFR variants and vaccination injuries or adverse events lead me to exactly one study. It is an open-access article on genetic variants and adverse reactions to the smallpox vaccine.
Overview of the study:
In a study conducted by Vanderbilt University, 131 people (average age of 23) received a vaccine for smallpox. The results showed that those individuals with an MTHFR C677T variant were more likely to have an adverse reaction to the vaccination. The study also linked other genes to an increase in adverse events.
Adverse events were defined as a skin reaction at the site of injection, fever within 30 days of the vaccine, or enlarged or tender lymph nodes. 40 study participants reacted to the vaccine and 69 participants did not.[ref] Smallpox vaccines have not been used on the general public in the US in over 46 years, and none of the study participants had previously received a smallpox vaccine. The vaccine contains a live virus that is similar to smallpox. It is given only to those who are at risk of smallpox exposure. [ref]
Other studies on MTHFR and vaccine excipients?
Some claim that excipients added to vaccines are the reason that MTHFR C677T carriers should not be vaccinated.
I did find a small study (50 participants) showing that those with the MTHFR C677T variant might be more sensitive to mercury. The study looked at the genes of 25 participants that had been diagnosed as sensitive to mercury compared with a control group of 25. The MTHFR 1298C/C genotype was more common in the mercury-sensitive group. (Some may question the statistics here with such a small group size.)
Mercury has been removed from children’s vaccinations since 2001 in the U.S. Seasonal flu vaccines for those over 6 years old can still contain mercury.
I didn’t find any other links between MTHFR variants and other common excipients in vaccines.
A study on vaccines and MTHFR that (hopefully!) doesn’t apply to children found that a cocaine vaccine worked better for MTHFR 677T/T genotype (decreased cocaine use and depression scores).[ref]
Conspiracy theory and other genes:
The ‘conspiracy theorist’ in the back of my mind wondered if the link between MTHFR and vaccine injuries was just being covered up — or perhaps deliberately not studied.
But… I did find several studies looking at the interplay between genetics and vaccination reactions. There has been work done looking at genetic variants and the role they play in both the effectiveness of vaccines and in regards to adverse events; those studies do not mention MTHFR as being involved in vaccine events.
One study found quite a few HLA gene variants as well as other immune system gene variants that do play a role in how vaccines work. The study examined the response to measles vaccinations and found that HLA type predicted whether the recipient would have a strong or weak immune response to the vaccine.[ref] Another study found that CD46 genetic variants also influenced response to the measles vaccine.[ref]
Someday, hopefully, we will be at the point where those who are most susceptible to a disease will be able to get a vaccine that is genetically right for them – at the right time and in the right amount.
Summing up the evidence:
- Not a lot of evidence pointing to the common MTHFR variants playing a role in vaccination adverse events.
- Carriers of the MTHFR C677T T/T genotype are more likely to react to the smallpox vaccine.
- Other genetic variants that have been found to increase the risk of either adverse events or vaccine effectiveness.
More to read:
- In silico analysis of autoimmune diseases and genetic relationships to vaccination against infectious diseases
- Adversomics: a new paradigm for vaccine safety and design
- The genetic basis for interindividual immune response variation to measles vaccine: new understanding and new vaccine approaches
- Tuberculosis Susceptibility and Vaccine Protection Are Independently Controlled by Host Genotype