I had a shingles vaccination Saturday. My shingles vaccine reaction started that afternoon.

A vaccine is a weak or small part of the disease that trains the immune system. The idea is that it prepares the body to fight the disease without the disease symptoms.

I do not want shingles. The intense neurological itching and pain does not seem like fun. But I am allergic to a component of the vaccines, so my body overreacts.

Normally when bacteria or virus enter the body, lymphocytes from the immune system fight them off by producing antibodies. These protein molecules fight the antigen (invader) and produce antibodies to help fight further infections. According to the Centers for Disease Control and Prevention (CDC), a healthy individual can produce millions of antibodies a day, fighting infection so efficiently that people never even know they were exposed to an antigen.

The immune system reaction has to be taught and can take several days to “ramp” up. In the case of shingles, measles, whooping cough, canine distemper, parvovirus, feline leukemia, rabies and many other diseases this can take too long. In the few days that it takes the body to respond, the infection has already taken over and can kill the person, dog, cat or other animal.

The vaccine uses dead or weakened antigens that cannot cause an infection, but the immune system still recognizes them as an invader and produces antibodies. After the immediate threat has passed, the antibodies will break down, but leave a type of immune cells called memory cells. The memory cells can produce an extremely fast supply of antibodies the next exposure and the invader is killed early in the infection.

There are a few different type of vaccines. Live attenuated vaccines are made from a weaker form of the disease. Because it is weaker, the bacteria or virus (pathogen) will not spread and cause sickness, but it will still teach the immune system to attack the pathogen. Because it is a live particle, it is an excellent simulation for the immune system. Sometimes they are effective enough for lifelong immunity.

However because they contain living pathogens, modified live vaccines cannot be given to people with weakened immune systems. This would include people undergoing chemotherapy or HIV treatment, because there is a risk the pathogen could grow, get stronger and cause sickness. Handling of the vaccine is more important because, these vaccines must be kept continually refrigerated so the weakened pathogen doesn’t die.

For humans modified live vaccines include: measles; mumps; rubella (MMR combined vaccine); chickenpox; influenza (nasal spray); and rotavirus. The dog distemper and parvovirus vaccines can be modified live viruses. Leptospirosis always is a modified live vaccine.

Killed or inactivated vaccines are made by killing the specific virus or bacteria with heat or chemicals. The dead cells are then introduced into the body. Although the pathogen is dead, the immune system can still learn from its antigens how to fight live versions of it in the future.

The dead vaccines can be freeze dried and easily stored because dead is dead and it can’t get any deader. With modern techniques, killed vaccines are safer, because the virus or bacteria cannot mutate back into the disease-causing form. This safety comes at a cost. Because the virus or bacteria is dead, it’s not as accurate a simulation of the real disease as a modified live virus. This means, it often takes several doses or booster vaccines to train the body to defend itself.

For humans, killed vaccines include: polio (IPV); Hepatitis A; and rabies. For dogs there are distemper, parvovirus vaccines and parainfluenza that are killed vaccines.

For some diseases, scientists have been able to isolate a specific protein or carbohydrate from the pathogen that, when injected into the body, stimulates the immune system to mount a protective response. Only a portion of the disease particle is actually administered. Identifying the best antigen of the pathogen is not always possible. Currently we can only produce a few vaccines this way: Hepatitis B; Influenza; Haemophilus Influenzae Type B (Hib); Human Papillomavirus (HPV); and Meningococcal vaccines.

When this protein is then produced on a safe bacteria or virus and is called a recombinant vaccine. In essence, scientists are able to take a harmless pathogen, dress it in the DNA of a more dangerous disease, and train the body to recognize and fight both effectively.

With recombinant vaccines the risk of adverse reaction is much lower. The newest shingles vaccine is a recombinant vaccine. One of the first dog Lyme vaccine is recombinant and cats have a line of feline distemper and leukemia recombinant vaccines.

Sometimes the bacteria cause damage that releases toxins. Some vaccines target the toxins and not the bacteria. (Think diphtheria and tetanus.)

In the future, we might have DNA Vaccines. This would only have a few parts of the pathogen’s DNA. Without any additions, these DNA strands would provoke an immune system response all by itself. Therefore, these vaccines would be very efficient, inexpensive and easy to produce. There are DNA vaccines for influenza and herpes are currently in human testing phases.

One of the important things about vaccines is that they also work on a community level. Some people can’t be vaccinated, either because they are too young, or because their immune systems are too weak, or their reactions are too severe. However, if there is no disease in their area because everyone around them is vaccinated, unvaccinated people are unlikely to come in contact with the disease to get sick. This protection is called herd immunity.

I have spent the week sick because of my vaccine. It is not my first vaccine reaction. That occurred from the swine flu vaccine at The Academy and resulted in an ambulance ride to the “real” hospital downtown.

Shingles happens after a person has had chickenpox. I don’t have to be exposed to anyone to get it. Therefore, I cannot rely on herd immunity. I guess I am comforted in knowing that my body is making a tremendous immune system response to the vaccine. The response is definitely much better than the disease!