A low-grade fever after the third vaccination requires drinking plenty of fluids, physical cooling, and temperature monitoring. And you need to rule out other diseases. After the third shot of vaccine, there may be adverse reactions, there may be fever, if it is only a low fever, there is no need to worry too much, more water, pay attention to rest, light diet, and good sleep habits, most of them are transient, can be relieved. If the temperature is high, you can give physical cooling, and monitor the temperature changes. If there is a persistent fever symptoms, do not relieve, it is best to go to the hospital to check the blood routine, blood sedimentation, calcitoninogen, c-reactive protein and so on to rule out the possibility of infection related pathogenic bacteria, for specific pathogenic bacterial infections, the use of appropriate measures of treatment. For example, bacterial infections should use penicillin, cefazoxime and other antibiotics. Specific medications should be administered under the guidance of a physician. After the third vaccination, you need to stay in the vaccination site for half an hour, no adverse reaction before leaving, to keep the skin clean, do not appear local skin infection.