Most of Us Have Viruses Sleeping Inside Us, and Spaceflight Wakes Them Up

Human spaceflight seems all the more remarkable when you consider the fact that our bodies didn’t evolve for space. We suffer in major ways as a result of microgravity and living in confined quarters hundreds of miles above the surface of the planet. Even our our immune systems take a hit, leaving us more susceptible to infection and disease as we spend more time in space.

A new study published last month in Frontiers in Microbiology reports that herpes viruses lying dormant inside the body become reactivated in more than half of all astronauts sent into space, potentially exacerbating what is already a high-risk environment. While we’ve yet to run into any kind of worrisome situation resulting from this phenomenon, those concerns loom larger as we set our sights on longer duration missions in orbit and seek to send astronauts back to the moon and on to Mars.

“NASA scientists have been studying the effects of spaceflight on the immune system for over 20 years,” says Satish Mehta, a scientist at the agency’s Johnson Space Center and the senior author of the new study. “It is believed that stressful life situations cause the lowered immunity, which causes viral reactivating.” And there are obviously very few situations that induce more stress on the human body than living and working in space.