Massachusetts Institute of Technology scientists have created a vaccine printer that can produce COVID-19 mRNA vaccines on the spot, potentially addressing the challenges of vaccine distribution such as the necessary infrastructure, medical expertise required for vaccination, and vaccine refrigeration. The researchers published their findings in Nature Biotechnology and shared that their printer prototype can produce 100 thumbnail-sized patches within 48 hours, with a promise to scale up to several hundred vaccine doses per day. The microneedle patches contain RNA vaccine molecules, which are encapsulated in lipid nanoparticles to maintain stability even at room temperature. The vaccine patches can be easily applied and do not require trained health professionals. The needles puncture the skin painlessly and dissolve on their own, with no special disposal method needed. Mobile vaccine printers like this one can aid in the distribution of RNA vaccines more broadly. The scientists plan to adapt the process and expand beyond COVID-19 mRNA vaccines to other types of vaccine formulations. However, some experts have raised concerns about the possible negative consequences of the current technology and gene-based injections that force healthy cells to produce a viral protein, which can weaken the immune system.