A new study published Wednesday in mSphere, a journal from the American Society for Microbiology, suggested a potential link between herpes and autism; More specifically, the study noted that contracting herpes simplex virus type 2 during pregnancy doubled the risk for autism spectrum disorder in male babies. Researchers examined the levels of maternal HSV-2 antibodies, where higher levels were indicative of a herpes flare-up in the mother — and found a correlation between elevated levels of HSV-2 antibodies and ASD diagnoses — but only in male babies. While the results are alarming, some experts have criticized the study's limitations and are telling pregnant moms not to ring their OB alarms just yet.
The study out of Columbia University examined data from the Autism Birth Cohort, collected by the Norwegian Institute of Public Health between 1999 and 2008. While data for more than 95,000 pregnant Norwegian mothers and their children was collected during the nine-year period, the Columbia study looked at just over 900 mothers and their children, with nearly even groups of children with and without ASD. Despite the findings, it's "really important to remember that not every mom who has HSV-2 is going to have a kid with autism," said Karen Jones, speaking to Science Magazine. Jones is a postdoctoral fellow in behavioral neuroimmunology at the University of California, Davis and was not involved in the study.
Even the study's senior author, Dr. W. Ian Lipkin, spoke to CNN about the study's own limitations: "It's not herpes, per se; it's the inflammation associated with the infection that's involved in the pathogenesis or pathobiology with this particular syndrome." The HSV-2 antibody levels that were examined were collected at mid-pregnancy, often resulting in herpetic inflammation a few weeks later.
One of the other big limits to the research noted by several experts is that the study only looked at mothers of boys who were diagnosed with ASD. While it's true that boys are four times more likely to have autism than girls, as Autism Science Foundation chief science officer Alycia Halladay told BuzzFeed, "Fewer girls are diagnosed in general. I’m not entirely convinced that the sex difference is really there." By only looking at the data of one sex of another, the Columbia study faces serious limitations in being able to make a truly compelling case linking herpes and autism risks for all children.
That said, contracting herpes during pregnancy does carry significant risks including premature birth, miscarriage, and a fatal infection if the baby contracts herpes in utero from the mother. Rachel Feltman, senior science editor for Popular Science, was quick to point out that the study didn't look at women who may have contracted herpes before they got pregnant:
While it's tempting to make it sound like herpes is the star of the new study, that's really nothing more than a cheap shot—an attempt to turn STI stigma into salivating clickbait. And in any case (one more time for the people in the back) the risky thing is to get herpes while pregnant, not to have it when you get pregnant.
If you're pregnant and worried, the best things you can do is prevent contracting an STI during your pregnancy and talk to your doc.