A vaccine is a substance that stimulates the immune system to develop immunity against specific pathogens without causing the disease itself. Vaccines may contain weakened or inactivated pathogens, toxoids, or recombinant antigens.
A vaccine is a substance that stimulates the immune system to develop immunity against specific pathogens without causing the disease itself. Vaccines may contain weakened or inactivated pathogens, toxoids, or recombinant antigens.