Penticton Herald

Don’t wait to vaccinate

- KEITH ROACH

DEAR DR. ROACH: I keep hearing that I should have my children tested for the MTHFR gene before vaccinatin­g them. What is the MTHFR gene? Does something about it lead to more vaccine injuries?

ANSWER: The MTHFR gene codes for the enzyme methylenet­etra-hydrofolat­e reductase, an important enzyme in making the active form of folic acid.

About 10 to 15 per cent of North Americans (higher in people of Hispanic or Italian descent) have a particular mutation in this gene (called the C677T, or “thermolabi­le” mutation).

People with this mutation are at higher risk for low active folic acid, which can cause a high blood level of homocystei­ne. This, in turn, is associated with an increased risk of blood clots and coronary artery disease.

I should note that it isn’t having the gene that seems to put people at risk, but the presence of high levels of homocystei­ne.

However, in a review of eight trials of people with high homocystei­ne levels who were treated with folic acid and other vitamins, there was no benefit in terms of decreasing blood clots, heart disease, cancer or death, despite the effectiven­ess of the supplement­s in lowering homocystei­ne levels.

There is theoretica­l evidence that methylfola­te may be more effective than regular folic acid at reducing homocystei­ne levels, but there still is no evidence that treatment reduces clinical risk.

There also is no evidence that people with MTHFR mutations are at higher risk during routine vaccinatio­n, and genetic testing for MTHFR mutations is currently not recommende­d by the American College of Medical Genetics and Genomics. I did find a paper showing that people with MTHFR gene mutations had a roughly doubled risk of fever, rash or enlarged lymph nodes from smallpox vaccine (which has a very high risk of adverse effects relative to routine child or adult immunizati­ons).

I don’t recommend testing. For people who know that they have a MTHFR mutation, it is reasonable to take a vitamin containing active forms of folic acid and vitamin B-12. As far as routine immunizati­on goes, because of the far greater benefit than risk, I recommend the vaccines for all people with or without MTHFR mutations, despite any theoretica­l increased risk in side effects.

Readers may email questions to ToYourGood­Health@med.cornell.edu.

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