Which of these vaccines contains live attenuated virus?

The vaccine that contains live attenuated virus is the MMR vaccine, which stands for measles, mumps, and rubella. Live attenuated vaccines use a weakened form of the virus that is still capable of stimulating an immune response without causing the disease in a healthy individual. This type of vaccine is effective in eliciting strong and long-lasting immunity because it encourages the immune system to respond similarly to how it would respond to a natural infection.

In contrast, the other vaccines listed do not contain live attenuated viruses. Hep-B (Hepatitis B) vaccine is a recombinant vaccine that contains surface antigens from the virus but not live virus. Similarly, the HIB (Haemophilus influenzae type b) vaccine is a polysaccharide vaccine, and the pneumococcal conjugate vaccine immunizes against a bacterial infection, not a viral one, by using polysaccharide antigens. These differences in vaccine design highlight the unique properties and immune responses associated with live attenuated vaccines like MMR.