Pinyin/Vaccine
A vaccine is a biological preparation that improves immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing microorganism, and is often made from weakened or killed forms of the microbe, its toxins or one of its surface proteins. The agent stimulates the body's immune system to recognize the agent as foreign, destroy it, and "remember" it, so that the immune system can more easily recognize and destroy any of these microorganisms that it later encounters.
Yìmiáo shì yìtú tōngguò cìjī chǎnshēng kàngtǐ duì yīzhǒng jíbìng xíngchéng miǎnyìlì de rènhé zhìjì. Yìmiáo bāokuò zhūrú mièhuó huò jiǎndú wēishēngwù de hùnxuányè, huòzhě wēishēngwù zhìpǐn huò yǎnshēngwù. Shǐyòng yìmiáo de zuì chángjiàn fāngfǎ shì zhùshè, dàn yě yǒu yīxiē kǒufú huò shǐyòng bíwùjì.