Common Adults Vaccines. Influenza Pneumococcal pneumonia Tetanus Vaccine Agents. Vaccines are currently administered either orally or by injection. Live-virus vaccines provide longer immunity than inactivated ones, but they can cause serious infection in people with weakened immune systems and have also been associated with severe medical disorders in rare instances. Inactivated bacteria, viruses, or toxoids.
Inactivated vaccines are safe even in people with impaired immune systems.
The weakened or inactivated agent in the vaccine acts as a sparring partner for the immune system. While fighting this imitator, the antibodies learn to recognize the real agent and attack it when the person becomes exposed to the infection. Currently a child must have 20 injections in the first year of life for full recommended immunity. Researchers are now studying the inclusion of even more vaccines within a single injection. There is some concern, however, that increasing use of combinations may reduce the potency of some of the vaccines within other combinations.