Scientists said Monday they have developed the first mobile printer that can produce thumbnail-sized patches able to deliver mRNA Covid vaccines, hoping the tabletop device will help immunise people in remote regions. These "microneedle patches" offer a range of advantages over traditional jabs in the arm, including that they can be self-administered, are relatively painless, could be more palatable to the vaccine-hesitant and can be stored at room temperature for long periods of time. "Until someone figures out the manufacturing scale-up issues for microneedle patches they will remain niche products," he told AFP