2000</ref>. Historical examples of successful vaccination programs include those for smallpox and polio. Recently, vaccines have been used to deal with sexually transmitted diseases such as the [[HPV]] virus. Some Christian groups have objected to the use of such vaccines since they could potentially encourage promiscuity in chidren. | 2000</ref>. Historical examples of successful vaccination programs include those for smallpox and polio. Recently, vaccines have been used to deal with sexually transmitted diseases such as the [[HPV]] virus. Some Christian groups have objected to the use of such vaccines since they could potentially encourage promiscuity in chidren. |