The point is that even blood contact in daycare or on a playground could potentially spread the virus. Sports, horsing around, fights involving blood or any means of blood exposure could potentially transmit the virus. We strongly encourage universal precautions when in contact with blood or bodily fluids. Live vaccines are alive and the virus grows after it is given to the person and actually causes an infection. These live vaccines are weakened viruses, so that people do not get as sick with the weakened virus and usually they cause no symptoms at all.
Inactivated vaccines are dead.
They don't grow. They usually require multiple doses and are often given in three or five doses. They have a different side effect profile. They are more likely to cause local reactions. Live vaccines generally work with one dose.