If protection is in place and sterilization is in place when doing nucleic acid, then cross infection can be prevented. 1. Protection in place: wear a mask correctly throughout the nucleic acid test, keep a distance of more than 1 meter from others throughout the sampling site when queuing up, and do not talk with others. When sampling, do not touch the sampling table and do not put down your belongings to avoid staining pollutants. Leave immediately after collection and do not open your mask and spit or vomit around the collection site. 2. Disinfection in place: After collection, place the used masks in the specified waste bin in a sealed place, change to a new mask and wipe your hands with disinfectant. When you return home, carefully disinfect and change the clothes on your body, then disinfect and wipe your belongings, such as cell phone, wallet, keys, etc. Finally, wash your hands repeatedly with soap and running water. By putting protection and disinfection in place when doing nucleic acids, the risk of cross-infection can be greatly reduced, so you don’t have to worry about it.