Jan. 29, 2004 -- Despite the ouch and some minor skin irritation, there's no real danger facing children who receive vaccines that contain aluminum salts, according to an exhaustive new analysis of previous studies.
After scouring through all the available medical data, researchers in Rome say there is no evidence that aluminum -- contained within the combined diphtheria, tetanus and pertussis vaccine commonly known as DTP and routinely given to children -- poses any serious or long-term side effects.
"Scare stories on aluminum-containing vaccines are not supported by evidence," lead researcher Tom Jefferson, MD, of Cochrane Vaccines Field in Italy, tells WebMD.
The pain and redness known to occur more readily with these vaccines may indicate that the shot is doing its job, says a leading vaccine expert not connected to the new report, published in the February issue of The Lancet Infectious Diseases.
Decades of Regular Use
"Aluminum salts have been added to vaccines since the 1920s because they enhance the immune response," says Paul Offit, MD, chief of infectious diseases and director of the Vaccine Education Center at The Children's Hospital of Philadelphia.
"If we were to take out aluminum from vaccines, we would have epidemics of several nasty infectious diseases," says Jefferson.
These salts are routinely added to childhood vaccines as well as vaccines against hepatitis, influenza, and pneumonia.
Offit says it's still unclear exactly how aluminum salts stimulate the body's immune response, making the vaccines more effective. "It appears to be several mechanisms," he tells WebMD.
What's clearer is their common result: An increased risk of skin redness and irritation and longer-lasting pain at the injection site compared with other vaccines without these salts. Because of this, many parents have been concerned about their safety.
No Serious Harm
After weeding out dozens of studies, the Rome researchers compared adverse reactions from vaccines containing aluminum to those with no aluminum salts. The information they gathered was on children under 18 months and 10-16 years old. As expected, they found aluminum-containing DTP vaccines were more likely than plain vaccines to cause redness or skin hardening in the younger children. And the older kids had pain lasting up to 14 days with the aluminum-containing vaccines. But there was no evidence of any serious problems in either group getting vaccines with aluminum salts.
"This is a very thorough, thoughtful review of the subject, and the findings don't surprise me at all," Offit tells WebMD. "Aluminum-containing vaccines have been used safely for decades."
In fact, this new report comes just eight weeks after Offit published his own study in Pediatrics looking at the safety of vaccines given to children that contain various by-products -- including aluminum salts, formaldehyde, gelatin, egg and yeast proteins, and thimerosal, a mercury-derived preservative.
With the exception of rare allergic reactions to the gelatin and egg products in some vaccines, he also found no danger from any of these additives, used to help prevent contamination and the spread of bacteria in multidose vaccine vials.
So what should you do about the pain and skin irritation that often accompanies these vaccines?
Nothing, advises Offit. The inflammation could indicate that the vaccine is doing its job, sending swarms of fighter cells to the injection site to battle the minute pathogens in the vaccine.
"To give your child an anti-inflammatory medication may, in fact, decrease that immune response."