Astronauts More Susceptible to Infection While in Space [Study]

Astronauts' genes change when they are in space. A new study suggests they are more prone to infection outside our planet because their immune system weakens.

Astronauts Have Weak Immune System in Space

There is mounting evidence that illnesses are more likely to affect astronauts. For instance, those who spend extended periods n the International Space Station (ISS) typically get rashes on their skin and respiratory and non-respiratory illnesses.

Researchers from the University of Ottawa analyzed blood samples collected from astronauts - 11 men and three women - before, during, and after flights. The participants lived aboard the International Space Station (ISS) for around four to six months between 2015 and 2019.

They noticed that the genes that play a role in one's immunity are deactivated in space, but they were "reactivated" with their immune function being restored to pre-flight strength when the astronauts returned to Earth.

Then blood tubes are sent to my laboratory at the University of Ottawa for isolation of white blood cells and then of the genetic material they call RNA-products of gene expression, Odette Laneuville, an author of the study, told Newsweek. The RNA was then sequenced at a high throughput sequencing facility, and the results were sent to my laboratory for extensive analysis.

The scientists discovered a group of genes in the astronauts that were inhibited while in space and then "reactivated" once more after returning to Earth. These genes code for proteins.

The study demonstrates that the expression of several immune-related genes rapidly declines when astronauts reach space, whereas the opposite occurs when they return to Earth following a six-month stay on the ISS, Laneuville added.

Their risk of infectious diseases hampers astronauts' ability to execute their extremely hard duties in space. Additionally, astronauts in space would have restricted access to care and medication if an illness or immune-related condition developed to a severe level requiring medical attention.

However, the researchers discovered that within a year of their arrival back on Earth, most of the damaged genes started to express themselves again at their pre-flight levels. This happened substantially sooner, after a few weeks on average.

The study was published in the journal Frontiers in Immunology.

Astronauts Prone to Bone Loss in Space

Aside from the new study, long-term space missions reportedly put astronauts' health at risk as they are threatened by severe bone loss. Astronauts lose 1% to 2% of their bone mineral density on average per month in the microgravity of space. Bone loss is a comparatively minimal consequence for a brief flight, according to the Government of Canada.

Bone loss can be a significant obstacle on a long space voyage, such as those envisioned for missions to Mars and beyond. While in space, astronauts may not experience any effects from this loss, but when they return to Earth, their weakened bones will be more brittle and susceptible to fractures. It is currently uncertain whether or not this bone loss will eventually plateau or if it will go on forever.

Bones are not static calcium structures; they continually change shape in response to external forces. Just like muscles, your bones will deteriorate if you don't use them.

Bone loss occurs in a gravity-free environment like space, where bones are no longer required to hold the body up against gravity. Due to the constant mechanical pressure that gravity places on the skeletal system on Earth, healthy bones must retain a specific density to sustain the body.

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