A new study found that the longer astronauts are in space, the more likely viruses like herpes, chickenpox and shingles will reactivate

By Maria Pasquini
March 18, 2019 06:14 PM
Credit: Michael Dunning via Getty Images

Astronauts face a greater likelihood of having viruses like herpes, mononucleosis and shingles reactivate the longer they’re traveling in space, according to a new study.

In the study published in February in the Frontiers in Microbiology journal, NASA researchers found that 47 out of 83 (53 percent) astronauts from short shuttle flights and 14 out of 23 (61 percent) on longer International Space Station missions “shed one or more herpes viruses” in their saliva and urine samples.

The study also found that “the shedding did not abate during the longer ISS missions, but rather increased in frequency.”

Additionally, the study determined that “larger quantities and increased frequencies for those viruses were found during spaceflight as compared to before or after flight samples and their matched healthy controls.”

To collect their data, researchers collected samples of blood, urine and saliva — as viruses are shed in bodily fluids — from astronauts before during and after short flights, which typically last between 10-16 days, and ISS missions, which last for over 180 days.

Credit: Michael Dunning via Getty Images

As for why spaceflight might result in a higher likelihood of virus reactivation, researchers pointed to a variety of factors.

Although after the initial infection, herpes viruses are “generally asymptomatic,” the study notes that “they may reactive during periods of increased stress, isolation and during times of immune challenge” — conditions which are all prevelant in space.

The study notes that sources of stress in spaceflight include “social separation, confinement, sleep deprivation, circadian rhythm disruption and anxiety” and that “there is increasing evidence to suggest that these spaceflight-associated stressors chronically amplify the release of stress hormones, which negatively affects the immune system.”

However, the lead author of the study, Satish K. Mehta, went on to note that although over half of astronauts experience virus reactivation, the majority did not experience any symptoms.

“Only six astronauts developed any symptoms due to viral reactivation,” Mehta said, according to CNN. “All were minor.”

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However, although the majority of astronauts won’t experience any symptoms, that doesn’t mean they couldn’t run the risk of infecting others once returning from their missions.

According to the study, “continued” post-flight shedding could “pose a potential risk for crew who may encounter newborn infants or any immunocompromised individuals on Earth.”

The study went on to note that in shorter flights, chickenpox and shingles viruses could remain reactivated for up to 5-3 days afterwards, while for longer flights, the viruses could keep shedding for up to 30 days.

The study went on to conclude that additional research needs to be conducted to determine “countermeasures to prevent viral reactivation.”

Additionally, the study recommended that whenever possible, astronauts should get vaccinated before beginning space travel.