Trying to conquer an alien world? Remember, never underestimate the small threats…like GERMS!
– Zim’s computer, from the “Invader Zim” episode “Germs”
My mouth was dry. My face was numb. And, as I sat there, spun out in my crew quarters, a thought passed through my mind: “Pertussis is an a*****e.”
The good news, of course, is that I didn’t actually have pertussis. Good thing, too! I can just imagine the headlines: “Year-Long NASA-Funded Mars Mission Simulation Terminated by Easily-Preventable Disease.” Nope, today’s brain stew was brought to you by the letters “T”, “d”, “a”, and “p”. Either my body was experiencing an immune system reaction to a deactivated version of a microscopic invader it hadn’t seen in a couple of decades, or, more likely, some virus had hitchhiked its way up the mountain on the box the Tdap vaccine was delivered in. Still, though it wasn’t exactly the most fun way to spend an afternoon, it was better than the possible alternative.
You see, going into isolation for an extended period of time carries a certain advantage. As the characters of the movie “Interstellar” once observed, you take only what you bring with you. In the case of viruses and bacteria, that means the only germs that came along with us were ones we were probably already immune to. Though we each brought our own colonies of microscopic organisms with us, these probably mixed around for a while, and it’s possible our own “microbiome environments” all look pretty similar by now – we have some crew-directed research investigating this very hypothesis.
The upshot is that our HI-SEAS mission isn’t just a year in isolation, a year away from Earth. It’s also a year relatively free from illness – no colds, no flu season. The dengue fever outbreak on the Hawaiian islands in late 2015 has yet to make its way to our Mars base. The same goes for any other type of isolation – crews in Antarctica, sailors manning US Navy submarines, or missions to the ISS and beyond.
Interestingly though, the advantage we have now has the potential – nay, the promise – to become a distinct disadvantage once the mission’s over. Bacteria and viruses evolve over time, helped along by having over 7.3 billion human incubators wandering the planet, interacting and intermingling. This is why, for example, a new flu vaccine is developed every year – scientists attempt to predict and prevent influenza strains that are expected to rise and become dominant in the coming months. Many of these evolutions and mutations occur slowly; so that, to our bodies’ immune systems, the new germs look similar to the old ones, and we’re able to fight off the new interlopers with little incident.
However, the six of us have been separated from this process, and our bodies likely haven’t had the chance to adapt to these incremental changes. It’s even possible that our own germs have evolved in a completely different direction from the rest of humanity’s. With only six walking, talking petri dishes instead of 7.3 billion to choose from, the mutations and evolutions probably haven’t had a chance to get as far along, though. Either way, once we leave the dome and rejoin the rest of humanity, without the benefit of being exposed to those incremental changes that the rest of humanity has experienced, the reaction to suddenly seeing a year’s worth of germ evolution may be a biological shock to our immune systems.
Hence the appearance of a Tdap vaccine on sMars for the Chief Engineer. As preparation for returning to Earth, I decided it’d be a good idea to go over my shot records with the crew doctor. With all those newly-evolved germs already gunning for me, I reckoned I didn’t need to give them any additional firepower by slacking off on my immunizations. A look over my records revealed I’d had several “Td” tetanus shots right on schedule over the last few decades. However, the Td vaccine protects only from tetanus and diphtheria, and doesn’t give the protection from pertussis that Tdap provides. We were unsure of whether these “Td”s in my records might have just been some doctor’s preferred shorthand for the full Tdap vaccine, but we decided not to take any chances. With pertussis, which is easily preventable through vaccination, showing a rise in the United States in the last few years, a small poke in the arm seemed like a reasonable and responsible trade-off.
Fortunately, because our mission is only a simulation and not a full-blown NASA space mission, we might not be completely at risk of getting sick the moment we walk out of here. As I mentioned before, the mild illness I felt the afternoon after my jab could have been due to an ordinary post-vaccination immune system response…but could also have been due to some germs tagging along for the ride from the doctor’s office on the vaccine’s packaging. Every couple of months, we receive simulated “resupplies” containing mail from home and additional food, tools, and science experiments. For real space missions, technicians pack cargo heading to the astronauts in “clean room” conditions – not only to prevent contamination of the supplies heading into space, but also to protect sensitive spacecraft components. Not having the budget of a real mission or access to fancy clean rooms, our mail and supplies are simply picked up from the post office or local supermarkets and delivered to the habitat, without any sort of extra cleaning or sterile handling. Though we take care to wash our hands after handling newly-delivered supplies, it’s possible that we’ve gained some amount of incremental immunity through contact with germs stowed away among these resupply caches.
But what about real Mars crews, who really will be truly isolated from planet Earth and all of our germs for years at a time? How will we protect the health of these explorers once they return home? I imagine there will be some sort of quarantine period involved after the astronauts return, much like the quarantine periods the crewmembers from the first Apollo missions to the Moon experienced to avoid the spread of potential contagions from the Moon to Earth (the requirement for quarantine was eliminated after Apollo 14 after NASA was completely convinced that the Moon was entirely void of life, including pathogens). The quarantine for the Martian explorers would serve not only to protect the Earth from possible contagions from Mars (we’re not quite convinced that Mars is as lifeless as the Moon), but to also allow for a gradual, controlled exposure to the Earth microbiome environment. I also imagine that the protective measures may include a regimen of immunizations and boosters, which may be administered during the waning days of their return cruise to Earth as well as during the quarantine period, just like my Tdap shot.
So, for you future Mars explorers out there, you might want to get used to hearing the phrase, “Please roll up your sleeve.”
A big thanks to Dr. Joseph D’Angelo, our mission support doctor “back on Earth”, for arranging to get the vaccine up here. Another big thanks to Dr. Sheyna Gifford for fact-checking this blog post (because, dammit Jim, I’m an engineer, not a doctor!), and for painlessly administering the shot.