VACCINATIONS

Vaccination is a cheap and effective way to prevent infections caused by viruses. The vaccines have been used to prevent viral diseases long before the discovery of the virus. Their use has led to a dramatic decrease in morbidity (illness) and mortality (death) associated with viral infections such as polio, measles, mumps and rubella. Smallpox has been eradicated.It is now available vaccines to prevent viral infections over thirteen in humans, and others are used to prevent viral infections in animals. The vaccines may consist of live attenuated virus or killed, or only the viral proteins (antigens).The live vaccines contain weakened forms of the virus that causes the disease. Live vaccines can be dangerous when administered to immunocompromised persons, because these people even in the weakened virus can cause illness original. However, the vaccine against yellow fever virus, obtained from an attenuated strain called 17D is arguably one of the safest and most effective vaccines manufactured. Biotechnology and genetic engineering techniques are used to produce vaccines subunits. These vaccines use only the capsid protein of the virus. The vaccine for hepatitis B is an example of such a vaccine.subunit vaccines are safe for immunocompromised patients because they can not cause disease.