High levels of mercury are known to damage the nervous system and kidneys. In addition, studies in the Faroe Islands, the Seychelles, and Iraq showed that fetuses might be harmed when pregnant women ingest large quantities of mercury. For these reasons, the FDA Modernization Act of 1997 required the FDA to compile a list of drugs and foods that contain mercury. At that time (and really since the beginning of the modern vaccine era), some vaccines used thimerosal, which contains ethylmercury as a preservative, so these vaccines were included in the FDA list.

We think of vaccines as antigens, but in truth vaccines contain additional ingredients that have functions ranging from stabilizing the antigens to preventing them from sticking to the vial.

Aluminum salts have been used as adjuvants for over 80 years, and hundreds of millions of people have received vaccines containing them. Whereas local reactions such as erythema, nodules, hypersensitivity, and granuloma formation have been reported, serious or persistent adverse events have not.

Many parents are leery of a “one size fits all” vaccine schedule and are interested in “alternative” schedules that “spread the vaccines out” over time. One of their main concerns, addressed above, is that too many vaccines in one visit could overwhelm the immune system.

The routine childhood immunization schedule in 2010 calls for as many as 53 separate vaccine doses by 18 years of age. The good news is that through all of this, 16 different diseases are prevented; the bad news is that some people wonder if it is just too much.

Natural infection may induce stronger and longer-lasting immunity than vaccines. Whereas immunity from disease often follows a single natural infection, immunity from vaccines usually occurs only after several doses and, in some cases, can wane with time.

Everyone agrees that vaccine-preventable diseases are less prevalent now than they were before vaccines were introduced. However, the myth still circulates that the diseases were disappearing before we had the vaccines.

The last 25 years have witnessed an unprecedented stream of innovative and sometimes controversial new drugs that have impacted not only the quality of our life, but also our society as a whole. Throughout these 25 years, MPR has been providing healthcare professionals with concise monographs for these new drug therapies.