A Lesser-known Problem of Galactic Conquest: Herpes in Space

The longer the trip, the worse it gets, NASA admits in a study that casts even more doubt on our future in the stars

Russian cosmonaut Oleg Kononenko conducts a spacewalk outside the International Space Station Space, December 11, 2018
Handout / Reuters

As our planet collapses around us, we are starting to suspect that sci-fi flix featuring stars in spandex terraforming Mars for the masses are far-fetched. But even the sourest skeptic among us couldn’t come up with this one. Never mind unsurvivable radiation or meteor strikes, forget alien invasions and deadly boredom. If anything’s flaring it isn’t Sol, it’s your skin. Space travel tends to reactivate herpes, NASA admitted in Frontiers in Microbiology. How apt. More than half the astronauts who flew on the Space Shuttle and the International Space Station suffered reactivation of latent herpes infection – and things grew worse the longer the missions lasted.

Shuttle missions usually last 10 to 16 days while missions to the space station are typically longer than 180 days, explains Bridgette Rooney of the GeoControl Systems Corp. in Houston, with people from NASA, the University of Colorado, and KBR Wyle Laboratories Houston.

Like on land, the virus awakes from dormancy and is reproduced in the astronauts’ skin cells, and appears in their body fluids. Like on Earth, stress has a lot to do with it, the scientists explain. At least most of the space cases were asymptomatic, they say.

Back at Mission Control

But the astronauts suffered from higher frequency of herpes reactivation, and in larger quantities, during spaceflight compared with control people on the ground, and also compared with their own data before or after flight.

The explanation is pretty obvious but bears repeating anyway: Physical, chemical and emotional stresses can trigger latent herpes. And space flight is terrible for one’s immune system, physically, chemically, and emotionally.

“NASA astronauts endure weeks or even months exposed to microgravity and cosmic radiation, not to mention the extreme G forces of take-off and re-entry,” explains the senior author, Dr. Satish Mehta of KBR Wyle. “This physical challenge is compounded by more familiar stressors like social separation, confinement and an altered sleep-wake cycle.”

The herpes outbreaks were detected during studies of the physiological impact of space flight, performed by collecting and analyzing saliva, blood and urine collected from astronauts before, during and after the flight. As one might expect, secretion of stress hormones such as cortisol and adrenaline are high in space. Those are known to suppress the immune system, explains the team.

Indeed, they also found that the astronauts’ immune systems, particularly the white blood cells that normally vanquish viruses, become less effective during spaceflight, and may stay subdued for as much as two months after the flight, they say.

A space probe falls towards the surface of Titan in this artist's conception of one of Saturn's moons. Space scientists hope that in the upcoming generations probes can be sent to explore the oceans of the large, icy satellites orbiting the outer planets.

Boldly scratching where no man has done before

The sample is small, but then how many people have left the Earth’s atmosphere? “To date, 47 out of 89 astronauts on short space shuttle flights, and 14 out of 23 on longer ISS missions shed herpes viruses in their saliva or urine samples,” Mehta stated. That, as said, is a lot, compared with their own samples before or after flight, or from healthy controls.

Herpes, as you may know, is actually a whole family of viruses and the ones retriggered on the astronauts were of four of the eight known types: the herpes simplex charmers responsible for oral and genital herpes; the ones causing chickenpox and shingles; Epstein–Barr virus; and cytomegalovirus. CMV and EBV have been associated with mononucleosis.

Only six of the astronauts reported symptomatic herpes, but asymptomatic need not be benign – especially on future, so far imaginary, long-term missions that would need to involve births. Space babies could be at terrible risk.

And as the team unhappily concludes, it’s bad enough when circling around Earth but given that the longer the mission, the greater the risk of herpes reactivation, deep-space missions beyond the moon and Mars could become intolerable. By the time we can do that, if that day comes, we need to have solved the problem of blocking herpes in all its forms.

Obviously the ideal countermeasure would be vaccination, which exists for varicella-zoster virus, the cause of chickenpox. Even though two-thirds of the world population is estimated to be infected with genital and/or oral herpes, no vaccine is in sight