Polio vaccine is usually provided in vials containing 10–20 doses of vaccine. A single dose of oral polio vaccine (usually two drops) contains 1,000,000 infectious units of Sabin 1 (effective against PV1), 100,000 infectious units of the Sabin 2 strain, and 600,000 infectious units of Sabin 3. The vaccine contains small traces of antibiotics—neomycin and streptomycin—but does not contain preservatives. In a generic sense, vaccination works by priming the immune system with an 'immunogen'. Stimulating immune response, by use of an infectious agent, is known as immunization. The development of immunity to polio efficiently blocks person-to-person transmission of wild poliovirus, thereby protecting
How the Riddler Got His Name Amanda Bell of "EW" gave the episode a "B+" and wrote, "The content of Nygma's riddles was paralleled not just by his own experience coming into his big badness, but also in the episode's other two story lines. 514A is, obviously, a literal reflection of Bruce Wayne, and the loneliness referred to in the first riddle applies to both Nygma and Gordon. Gordon's quest for truth and family, compounded by his current isolation, makes him vulnerable to Frank’s ploy right now — if that's what it actually is. For a segment devoted to such a cunning wordsmith, this episode quite