Are Vaccines Safe?

Vaccines are some of the most tested and closely monitored medicines we take. Thousands of hours of research from around the world go into each vaccine to ensure they are safe and effective before they are distributed to the public. Even after they are released for use, vaccines are tested continually and monitored for safety.

For vaccines to be worthwhile, it is important that they have fewer side effects than the harm that diseases themselves would cause. There are many ways that vaccines can be formulated to make sure they are safe and effective. Some vaccines may contain a much smaller dose of the bacteria or virus than would be present in the disease itself. Live virus vaccines can be cultured in environments that promote milder strains, making a case of measles feel more like a common cold. Other vaccines may omit the specific antigens in a disease that are known to cause bad reactions.

When we share a disease’s definition with our immune system through vaccination, we have an opportunity to pick and choose the antigens that will produce safe and effective immunity and leave out problematic antigens that may cause more harm than good. For example, imagine that we wanted to create a vaccine for strep throat.

Let’s say that your body identifies the strep bacteria by these marks

Let’s say that your body identifies the strep bacteria by these marks

Now, imagine that some of your own cells have these marks on their surface

Now, imagine that some of your own cells have these marks on their surface

Note that two of these marks look the same. The strep bacteria and your own cells share a similar shape.

Note that two of these marks look the same. The strep bacteria and your own cells share a similar shape.

As a result, sometimes children develop autoimmune disease after strep throat infections. So, if we were to make a vaccine for strep throat, one way to make that vaccine safer than catching strep throat would be to omit that shape. The remaining shapes would be enough for your body to identify it as strep bacteria but would reduce the risk that your body attacks itself.

The vaccine would look like this

The vaccine would look like this

The vaccine includes all the shapes of strep bacteria without the shape that is found on your cells.

This was the process used in the current diphtheria, tetanus, and pertussis (DTaP) vaccine and is one of the reasons that babies tolerate the vaccine much better than the effects from actually catching pertussis. By reducing the intensity of a reaction that a disease would cause, a vaccine is far less likely to trigger an unwanted reaction than the disease itself. Vaccines enable your immune system to more accurately and safely distinguish between what is disease and what is your body.

Shona, Ashland, OR

"When my daughter was about 1 year old, there was a lot of discussion in the media about the safety and potential side effects of vaccines. I became concerned and decided to learn more about the pros and cons of vaccines.

In reviewing reputable resources and discussing my concerns with my pediatrician, I found the advantages far outweighed any potential side effects, and the question then became, how could I not vaccinate my child? As any
reasonable parent would, we want to protect our children. 

Vaccines are the best preventable care we have to protect against disease, and I fully welcome and endorse all vaccines now."