How we are born - by Caesarean-section or vaginal delivery - alters how our immune system responds to vaccines, a Scottish and Dutch study suggests.

Babies born vaginally had double the level of protective antibodies produced after childhood vaccines.

The researchers said the difference was caused by the types of good bacteria, which colonise our bodies at birth.

And while C-section babies do get protection, it may need topping up with probiotics or extra vaccines.

Our birth is the moment we emerge from the sterile world of the womb to one teeming with microscopic life.

Microbes - including bacteria, fungi, viruses and archaea - make our bodies home and eventually outnumber our "human" cells.

This hidden half of ourselves is known as the microbiome and one of its roles is training our immune system early in life.

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There are also valid concerns about the safety of the SLS and Orion hardware. These vehicles are large, complex machines that will only fly infrequently, at most once a year. At such a flight rate, this launch system will always be experimental.

It can reasonably be argued that Starship is also not safe to launch on and land back on Earth. It, too, is a large and complex vehicle that will come back through Earth's atmosphere, dissipate heat, and perform delicate maneuvers before landing under the power of its own engines. Even though Starship will launch at least dozens of times per year, the vehicle is unlikely to meet NASA's safety requirements for humans for a long, long time. So Starship-only missions to the Moon are not a near-term solution.

Something even the prophet cannot predict
However, there is an alternative, the source suggested. NASA presently has a vehicle it has deemed safe enough to launch humans into space and back. That's SpaceX's Crew Dragon spacecraft, which launches on the rocket that owns the world record for the longest streak of successful launches—the Falcon 9. By the mid-2020s, Crew Dragon will already have launched humans into space dozens of times.

The safest and lowest-cost means of completing an Artemis mission to the Moon, therefore, may involve four astronauts launching to a fairly high altitude in low-Earth orbit on Crew Dragon and rendezvousing with a fully fueled Starship. The astronauts would then fly to the Moon, land, and come back to rendezvous with Crew Dragon in Earth orbit. They would then splash down on Earth inside Dragon.

This architecture is less risky because it doesn't involve launching on SLS, nor does it require two rendezvous and dockings in lunar orbit, far from Earth. The crew would only spend a couple of more days aboard Starship than they would during the existing Artemis III plan, so Starship life support should be up to the task. If you care about costs, this plan also excludes the $4.1 billion launch cost of Orion and the SLS rocket and substitutes Crew Dragon, which would be on the order of one-twentieth of the cost.