Can you get an infection in space?

Hello Houston! Do we have a problem? If there is one place where you don't want to get sick, it's in space: you are far from everything, in a confined space, with extremely limited ability to return to Earth... Not to mention that space travel is expensive and that astronauts have a mission to accomplish. How do space agencies avoid epidemics aboard space stations? Does it still happen that an astronaut gets sick? How is he cared for then?

In space, during an infection, the chain of contagion is short and rapid because the space available on board is reduced and external ventilation is non-existent. In other words, a universe that is very conducive to the spread of contagious diseases, such as colds. “Space medicine was born sixty-three years ago with Gagarin, and we observed infectious episodes from the first crew missions,” recalls Dr. Guillaume Weerts, former doctor responsible at ESA for astronauts.

This is reinforced by the absence of gravity: if you sneeze in a ship, the particles are not subject to gravity and remain suspended in the air of the shuttle or station until they enter the system. shuttle air filtration. According to Dr Guillaume Weerts, “a pathogen could thus remain suspended in the air for a certain time”.

In addition, it is very complicated, if not impossible, to isolate a patient. During a crew change, there can be up to 12 astronauts on board the ISS at the same time in a space the size of a small apartment! “Viral infections on board the ISS are very rare, but when an astronaut has one, then the whole crew gets it,” explains Guillaume Weerts, .

To avoid epidemics on board, the simplest thing is obviously to avoid taking pathogens on board. The crew is thus placed under surveillance for several weeks and undergoes a more or less strict quarantine for around ten days before takeoff. Human contact is controlled. “We ensure that people in contact with astronauts do not show signs of contagiousness.” Contact with children in particular is very supervised, because they are more often carriers of pathogens than adults. “We were recently forced to postpone a takeoff due to an illness that was likely to develop,” says Guillaume Weerts.

The medical team is not aiming for total asepsis, which would be impossible, but rather a reasoned approach to risk assessment and management. For example, testing for viral or bacterial infections is only done if astronauts develop clinical signs, such as a fever.

“We do prevention but zero risk does not exist. A sick crew can quickly become unmanageable because the capacity to treat the infection in flight is limited,” explains the ESA doctor. There is no doctor on board and the pharmacy is very limited. No bacteriological analysis is possible, for example.

In each crew there are two astronauts trained in medical assistance (“Crew Medical Officers”, CMO) capable of performing basic medical procedures like paramedics do. Assisted by a ground medical team, CMOs can use the first aid kit which contains aspirin, anesthetics, medication for dental pain and a defibrillator.

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You can also be “allergic” to space! The Apollo 11 mission team contracted allergic rhinitis, manifested by sneezing and nasal congestion, caused by particles from the star suspended inside the spacecraft. The ailment was poetically named “lunar hay fever.”

In a France Inter column in 2021, Thomas Pesquet also testified to the different discomforts that we feel in weightlessness: “Space sickness exists... some people need to adapt. The symptoms are dizziness, nausea, you may be a little tired. It's like seasickness, some people have it very badly and are unable to do anything. And then the fluids are not distributed in the same way in the body and mean that we are a little congested, that we can have a headache, have difficulty sleeping..."

More than these small inconveniences, however, Dr Guillaume Weerts explains that it is the space adaptation syndrome which represents the main concern for the health of astronauts. “The human body is not adapted to weightlessness, our biological systems do not all react to it at the same speed, in a few days the cardiovascular system is modified, in a few weeks it is the turn of the muscular system, then the bone system from two months. We lose 1 to 2% of our bone mineral mass per month, after 6 months it is 10 to 15%, which can increase the risk of fractures. In order to limit the risk, astronauts' trips are limited in time and countermeasures are put in place such as regular in-flight sports training. Creating gravity in a spacecraft is a goal that will improve health on board.

For the moment, there is nothing to confirm that life, even in the form of bacteria or viruses, is present anywhere other than on Earth. The probability of being infected by a pathogen of extraterrestrial origin is therefore considered negligible.

But could we find bacteria specific to the ISS? The story of the bacteria Solibacillus kalamii is remarkable. Indeed, this organism discovered in the filters of the ISS in 2011 has until now been found nowhere else on the surface of the Earth. The latter produces spores that resist the extreme conditions of space. It is probably the descendant of a bacteria brought back by the astronauts which evolved on its own path in this hostile and gravity-free environment.