Toddler survives smallpox vaccine reaction

By Maggie Fox, Health and Science Editor

WASHINGTON (Reuters) - A two-year-old boy who developed a serious reaction to his father's smallpox vaccination has recovered but disease detectives found infectious virus all over his house, the Centers for Disease Control and Prevention reported on Thursday.

The Indiana toddler developed a rare rash known as eczema vaccinatum after playing with his father, a soldier vaccinated for deployment in Iraq, reported Dr. John Marcinak of the University of Chicago and CDC experts.

Experimental treatments helped the child, but the CDC said the incident showed that care must be taken by people who receive the smallpox vaccine.

It was the first case of eczema vaccinatum reported in the United States since 1988, the CDC said. The child was hospitalized for 48 days but should suffer no long-term consequences other than possible scarring, said the report, published in the CDC's weekly report on death and disease.

Pox viruses can survive on inanimate objects so experts tested the family's home.

"Multiple swab samples obtained from the home (e.g., from a bathroom washcloth, a slipper, a toy drum, a night stand, a booster seat, and an ointment container) and from items brought to the child's hospital room (e.g., an infant drinking cup and a car seat) were positive for vaccinia virus DNA," the researchers wrote.

They steam-cleaned the home and washed clothing and linens after an acid pre-treatment.

The World Health Organization declared smallpox eradicated in 1979. The U.S. government reinstated smallpox vaccination for military personnel and selected healthcare workers because of fears the virus could be used in a biological attack.

"The U.S. Department of Defense had vaccinated approximately 1.2 million persons as of March 2007," the report reads.

The smallpox vaccine uses a related and usually harmless virus called vaccinia. It is scratched into the skin and forms a pustule that scabs over and falls off.

People with eczema and immune conditions can develop a serious reaction if they are vaccinated or come into contact with the blisters of a vaccinated person.

The soldier received the vaccine even though he had a history of skin allergies.

"His deployment was delayed, so he made an unplanned visit home to visit his family in Indiana," the report reads. "His routine activities with his son included hugging, wrestling, sleeping, and bathing."

The child developed a rash and later severe illness. After a week of experimental treatments he began to get better.

The treatments included an antiviral drug made by Siga Technologies Inc., vaccinia immune globulin and the antiviral drug cidofovir, made by Gilead Sciences Inc..