Preventive Medicine: More on Vaccines


Vaccines are important for prevention of many diseases

What are they?

Vaccines are substances designed to protect people against disease by assisting the body to develop its own immunity against certain pathogens. These germs can enter the body, causing disease.

There are 3 basic types of vaccines: Live, killed and Recombinant DNA. Most vaccines are given by injection, into the muscle, and a few can be taken orally.

In any case, both live and killed vaccines can be used to treat the same disease.

Live vaccines are made in a lab from the germ, usually a virus that causes a disease. Live are weakened ( attenuated) with the intention of triggering the body’s own immune system to generate an immune response without causing the disease. Attenuated viruses have been developed for the following: chicken pox , measles, mumps, polio (oral dose), rubella, and yellow fever. Attenuated bacterial vaccines include: Typhoid fever and bacillus -Calmette-Guerin ( used for tuberculosis).

The controversy: Should live vaccines be given to infants since infants do not have a fully developed immune system?

There are experts who believe that these vaccines have the potential to cause autism and autoimmune diseases; others dismiss this claim. Hopefully, as research continues, there will be solid evidence for or against live vaccines.

Killed vaccines also referred to as inactivated vaccines are composed of all, or a portion of a disease-causing organism that has been killed, which means that it can no longer reproduce and cause disease. Because they are killed, they trigger a weaker response by the immune system than live vaccines.

Because they are killed vaccines, they tend to be safer for children, especially those under 1 year, whose immune systems are not fully developed.

Killed vaccines have been developed for the following: Cholera, hepatitis A, hepatitis B, influenza, Lyme disease, pertussis, polio (injection),  rabies and typhoid. Another type of killed vaccine is a toxoid which is made by inactivating the poisons (toxins) that are produced by bacteria and viruses. Vaccines against diphtheria and tetanus are made this way.

Recombinant DNA Vaccines:  They are Genetically engineered.  This means that researchers have manipulated the genes to create the vaccine.

An example: Hepatitis B Vaccine. To make this vaccine, researchers take specific genes from the hepatitis B virus and add them to a culture ( baker’s yeast). This allows the virus to  reproduce.

Once the virus has reproduced, minuscule amounts can be mixed with solution and injected.

Some experts believe that recombinant DNA vaccines are safer and more effective than live or killed vaccines because they contain only a portion of the infectious agent, so they cannot cause an infection.

Health Problems: some experts believe that Recombinant DNA  can trigger the immune response to produce antibodies which can attack the body causing various diseases.

The 10 Vaccines

The following are the 10 vaccines recommended by the Federal Government and mandated by the states for children:

Hepatitis B: Typically the fist vaccine children are given. With the first injection give shortly after birth and the 2nd within 1-4 months of age, and the third between 6 and 18 months.

DTaP: Diphtheria, tetanus and acellular pertussis ( whooping cough) , a revision of the original DTP vaccine. A total of 5 injections are administered over a period from 2 months to 4-6 years.

Hib: Haemophilus influenza type B, 4 injections given at 2,4,6, and 12-15 months of age

Polio: the injectable from the polio vaccine. IPV (inactivated polio vaccine) has been recommended over the oral polio vaccine since January 1, 2000. It is give at 2, 4, and 6-18 months. Followed by a booster does at 4-6 years.

MMR: a combination of measles, mumps and rubella vaccine, given at 12-15 months of age with a second dose given at 4-6 years.

Varicella: Chicken pox, given as a single dose between the ages of 12 months and 12 years.



Taken in part from: Mitchell, D. ( (2007). Collins Children’s Pill Guide. New York, NY. Harper Collins.