Routine smallpox vaccine risky for eczema patients

Last Updated: 2002-09-10 11:00:09 -0400 (Reuters Health)

NEW YORK (Reuters Health) - As health experts and government officials debate the merits of widespread smallpox vaccination amid renewed concerns of bioterrorism, a report cautions that the vaccines can trigger severe skin reactions among susceptible individuals.

People with immune deficiency diseases such as AIDS, those on immune system-suppressing drugs, such as transplant patients, and people with eczema are all vulnerable to vaccinia, a virus related to the smallpox virus that is used in vaccines.

In people with eczema, exposure to vaccinia through the vaccine or by contact with someone who was recently vaccinated can cause a condition that can lead to scarring, blindness and even death.

The US Centers for Disease Control and Prevention (CDC) recommends that all laboratory technicians who have contact with the smallpox virus get immunized. It is not recommended that individuals with eczema or a history of the skin disorder, also known as atopic dermatitis, be "vaccinated under routine circumstances," according to Dr. Renata J.M. Engler from the Walter Reed Army Medical Center in Washington, DC, and colleagues.

Given the rise in the number of people who suffer from eczema, up to one-half of the US population may be ineligible for routine smallpox vaccination, the researchers estimate in a report in the September issue of the Journal of Allergy and Clinical Immunology.

"A major challenge lies in the ability to protect the population from the disease while minimizing the considerable side effects from the vaccine," the researchers conclude.

They call for more research into clinical markers to identify people who are prone to side effects, and into how people with asthma, an allergic disorder, respond to vaccinia vaccination.

Doctors should also screen individuals for eczema if a smallpox vaccination campaign is launched in the US, although in some cases, such as after a bioterrorist attack, the benefit of vaccine could outweigh the risk. If an exposed individual is vaccinated within 4 days, the vaccine can reduce symptoms or prevent the disease, whose initial signs include headache, vomiting and fever. Subsequently, pus-filled lesions form on the head, face, and in some cases, on other parts of the body.

Prior to 1972, all Americans were vaccinated against smallpox, a viral infection that is fatal in 20% to 40% of unvaccinated individuals. The eradication of the disease was declared in 1980 and over the next several years, all countries stopped their national vaccination campaigns.

Officially, smallpox exists only in two laboratories--one in the US and the other in Russia. However, reports that other governments or terrorist groups may have samples of the deadly virus have sparked fear of bioterrorist attacks.

SOURCE: Journal of Allergy and Clinical Immunology 2002;110:357-365.

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