The 12 countries -- the US, Canada, Australia, UK, Spain, Portugal, Germany, Belgium, France, the Netherlands, Italy and Sweden -- are not endemic for monkeypox virus, meaning the virus is not typically found unlike some countries in Central and West Africa.
A pair of studies have shown that Omicron infection produced even better immune responses than a booster shot in vaccinated patients. The data comes as Omicron continue to fuel outbreaks around the world, most notably in China.
The ground-breaking experiment, detailed in the journal Communications Biology on Thursday, has given researchers hope that it may be possible to one day grow plants directly on the Moon. "This research is critical to NASA's long-term human exploration goals," said Bill Nelson, the head of the US space agency. "We'll need to use resources found on the Moon and Mars to develop food sources for future astronauts living and operating in deep space."