Ever since the beginning of time mankind and every other animal creature on earth had to learn to defend against predators. Animals kill each other for food and territory and we all battle disease and pain.

Human beings don’t kill each other for food and territory any more, at least it doesn’t happen in our civilized, modern society; but we spend lots of money and effort trying to investigate diseases in order to learn how to prevent and treat them.

Over the last 100 years the life expectancy for humans has been increased by a couple of decades. During the 19th century, a person of 40 years of age was already considered old, since he/she could expect to have about 20 more years around the mortals, if lucky. Today, a 40 year-old man or woman is in his prime time. We don’t consider a person old until in his 80’s. I can tell you that my personal definition of “old” has changed as I added birthdays to my calendar.

One of the biggest success stories of the 20th century includes the discovery and world-wide use of serums that, when injected, stimulates the production of defenses against infectious agents in such a way that, when you are in contact with the infective organism, it reduces the chances of getting sick by it. Very cool, right?

That is the way vaccines work.

And some vaccines have a double advantage: they protect you against the disease, but they also protect the whole community you live in. Every one of us becomes a vehicle to spread disease when we get sick with an infectious agent. When we are immune to it, we create a shield of protection for those around us, even those who are not immunized. If we all become immunized, the infectious agent will have nowhere to go and it could be eliminated from the face of the earth. This is exactly what happened with Smallpox; when enough people became vaccinated, the virus didn’t have any more susceptible hosts and disappeared.

The World Health Organization had the goal of eradicating Polio from the earth by the beginning of the 21st Century. The goal is not going to be met and many countries still suffer from this devastating disease. I just read an article explaining how politicians in some countries in Africa are discouraging their citizens from obtaining the vaccine, brought to them free of charge, because they don’t trust the intentions of those trying to promote it. Sounds familiar?

During the yearly flu outbreak many people can’t get vaccinated. It may be because they are allergic to some of the components of the vaccine; it may be because they have some disease of their immune system that keeps them from responding to the vaccine; they may be too young or too old. Some groups are at increased risk of getting sicker with the influenza virus, such as the elderly or pregnant woman. When you immunize a significant number of people, those individuals are more likely to be protected. Immunized individuals are not going to pass the flu along to their 80-year-old neighbor who may have asthma; they are not going to transmit it to the pregnant woman waiting in line next to them at Target; they are less likely to infect the small child on chemotherapy sitting next to them in church. This is HERD immunity. This is the way vaccines protect even those who are not vaccinated, by creating a shield of immune people around those who are susceptible.

In order for herd immunity to be effective the majority of the population must be immunized, that is, the number of susceptible persons must be minimized and the number of immunized persons must be maximized.

Talk to your doctor about this issues. Get informed. Get the facts.

Like Dr. Laura would say: “Go and do the right thing”.

Marta Katalenas M.D.

About the Author

Dr. Katalenas

Dr. Katalenas is a pediatrician and owner of The Pediatric Center of Round Rock and the author of the book "The Step Up Diet: From Scratch… The Quality, Quantity, and Timing Solution to Childhood Obesity", a guide to healthy cooking and eating for busy families.