Shingles Increases Risk of Developing Multiple Sclerosis

According to a recent study, an outbreak of shingles has the possibility to quadruple the risk of an individual developing multiple sclerosis (MS) over the course of the year following. The Chinese researchers who performed the study reported that the overall risks were small, though.

Viruses have long been thought to play some role in triggering MS, but this is the first study to implicate the herpes zoster virus conclusively as one such virus.

Shingles is a viral infection caused by the herpes zoster virus, the same virus which causes chickenpox. Once an individual has the chickenpox, the virus can lay dormant in their system until it reactivates, sometimes years later, as shingles; it usually manifests as a painful rash.

Herng-Ching Lin, epidemiologist of Taipei Medical University in Taiwan, worked with colleagues and studied a total of 1,262,200 participants, splitting them into two groups: 315,550 of the participants had herpes zoster while 946,650 were placed into the control group.

The researchers followed these participants for one year, monitoring them for the development of MS. Twenty-nine individuals from the study group and twenty-four participants from the control group developed the autoimmune disease over the course of the next year.

The researchers accounted for factors such as family income and geographic region, both of which are known to play a role in the development of MS, and they discovered that the herpes zoster group was 3.96 times more likely to develop MS than the control group. In these cases, MS generally developed roughly 100 days following the shingles outbreak.

Lin, along with fellow study authors Jiunn-Horng Kang, Jau-Jiuan Sheu, and Senyeong Kao, reported that their “findings support the notion that occurrence of MS could be associated with herpes zoster attack. We found a significantly higher risk for MS within one year of herpes zoster attack compared with the control population.”

The authors cautioned, however, that these results would most likely not be able to be applied to the rest of the world, as MS has a lower incidence in Asian populations than in Western ones.

In an editorial accompanying the report, Mexican researchers wrote that they agreed with the Chinese researchers; they said that while the results provide new insights into the causes of MS, the research should be performed again in other areas of the world in order to be applicable.

The research is published in the Journal of Infectious Diseases.