Vaccines such as polio are included in this type of immunization. These are such as polio, are engineered to be less virulent than the disease they aim to prevent. Attenuated vaccines are longer lasting do not require booster shots.
Vaccines such as polio are included in this type of immunization. These are such as polio, are engineered to be less virulent than the disease they aim to prevent. Attenuated vaccines are longer lasting do not require booster shots.