THURSDAY, Sept. 4 (HealthDay News) -- Vaccine safety experts say that almost all kids who are allergic to vaccines can receive vaccinations with close monitoring and a set of standard precautions.
Reporting in the September issue of Pediatrics, a team of experts led by the Johns Hopkins Children's Center put forth a step-by-step set of instructions -- an algorithm -- to help physicians evaluate and immunize children with known or suspected vaccine allergies.
Allergic reactions to vaccines are extremely rare -- with only one or two per million vaccinations -- but they can be serious and even life-threatening. Symptoms of a severe allergic reaction are usually immediate, may include hives, swelling, wheezing, coughing, low blood pressure, vomiting or diarrhea, and can lead to full-blown, life-threatening anaphylaxis.
To help pediatricians differentiate between these serious reactions to benign responses, the investigators analyzed the available evidence on vaccine safety and allergies.
"We cannot reiterate enough that the vaccines used today are extremely safe, but, in a handful of children, certain vaccine ingredients trigger serious allergic reactions," study author Robert Wood, chief of pediatric allergy and immunology at Hopkins Children's Center, said in a hospital news release. "For the most part, even children with known allergies can be safely vaccinated."
The new sequence of instructions developed by the research team is intended to be used for children who have already had or are at high risk for having allergic reactions to vaccines.
In these cases, the algorithm advises a workup by an allergist, who can perform skin prick testing or blood tests, to detect the presence of an allergy to a suspected allergen in the vaccine.
In many cases where a child is allergic to an allergen in a vaccine, an alternative form of the vaccine that is free of the allergen can be used. If an allergen-free vaccine is unavailable, many children can still be vaccinated under the supervision of a physician for several hours after the vaccination. Immunizations of children with known vaccine allergies should be administered at a clinic that is equipped to treat life-threatening reactions or in a hospital intensive care unit.
Physicians also have the option of checking the child for immunity to the disease that is being vaccinated against. If the child is already immune, further doses of the vaccine may not be necessary.
"Most children who have had an allergic reaction after a vaccine can still be vaccinated against other diseases safely, and some can receive additional doses of vaccines they might have reacted to," investigator Neal Halsey, an infectious disease specialist at Hopkins Children's and a professor of international health at the Johns Hopkins University School of Public Health, said in the news release.
More information
The American Academy of Family Physicians has more about childhood vaccines 
.
MONDAY, Aug. 18 (HealthDay News) -- Recently discovered so-called free radicals that are attached to small particles of air pollution could cause lung damage and perhaps even lung cancer, researchers report.
If confirmed through further research, the finding could help to explain why nonsmokers develop tobacco-related diseases like lung cancer, said lead researcher H. Barry Dellinger, the Patrick F. Taylor Chair of environmental chemistry at Louisiana State University.
It has been known for years that free radicals exist in the atmosphere, and these atoms, molecules and fragments of molecules can damage cells. It had been thought that these particles, which can be produced by combustion, exist for less than a second and then disappear.
"What I found out is that combustion-generated particles contain environmentally persistent free radicals," said Dellinger. "When the radicals are associated with particles, they can apparently exist indefinitely."
These free radicals are remarkably similar to the free radicals found in cigarette tar, Dellinger said. "The implication is you can have the same environmentally related diseases by exposure to airborne fine particles that you can get from cigarettes," he said.
Dellinger noted, however, that one would have to smoke about 300 cigarettes a day to be exposed to the same level of environmental free radicals found in moderately polluted air.
The findings were to be presented Monday at the American Chemical Society annual meeting, in Philadelphia.
The persistent free radicals (PFRs) discovered by Dellinger's team attach themselves to small particles of air pollution as they leave smokestacks, car exhaust pipes and household chimneys, and continue to exist as free radicals. Particles of air pollution containing metals, such as copper and iron, are more likely to remain in the atmosphere and can carry these PFRs great distances, Dellinger said.
As PFRs are inhaled, they're absorbed by the lungs and other tissues and cause cell damage that can lead to problems such as asthma, emphysema and lung cancer. However, there's still no direct evidence linking PFRs to any of these diseases, he said.
Dr. Neil Schachter, a professor of pulmonary medicine at Mount Sinai Medical Center in New York City, thinks it's premature to blame persistent free radicals for the adverse effects of air pollution.
"These airborne free radicals are of interest, but I am not sure we are at a point where our scalpel is sharp enough to dissect the individual components of air pollution that cause problems for people," he said.
It's possible that persistent free radicals are responsible for the respiratory damage caused by pollution, Schachter acknowledged. "There are studies that show that modifying free radicals can alter the course of disease," he said. "But the implications of this -- what it means to clinics, what it means to doctors, what it means to regulators -- I think we are a long way from pulling that together."
More information
For more on the health risks posed by air pollution, visit the U.S. Centers for Disease Control and Prevention.