University of Chicago Medical Center team diagnoses rare infection

University of Chicago Medical Center team diagnoses rare infection

March 16, 2007

On March 3, 2007, a two-year-old boy suffering from severe eczema and an unusual, widespread rash was transferred from St. Catherine's Hospital, in East Chicago, IN, to the University of Chicago's Comer Children's Hospital where he was diagnosed with eczema vaccinatum--a rare, severe, adverse reaction to the vaccinia virus. Physicians at Comer notified the public health authorities and on March 8, the Illinois Department of Public Health Laboratory Response Network confirmed this diagnosis.

Vaccinia is used to vaccinate military personnel and health care workers against smallpox. The source of this child's infection was his father, who had been vaccinated in late January in preparation for military deployment. When deployment was unexpectedly delayed, he was allowed--in mid-February, three weeks after vaccination--to visit his family in Indiana. During this visit he came in close contact with the child, who has long-standing severe eczema, which increases the risk and potential severity of a vaccinia infection.

Two weeks later, in early March, the child developed a rash and his mother took him to St. Catherine's Hospital. When the rash continued to spread, physicians there arranged his transport to the University of Chicago Medical Center.

The child's mother, who has stayed with him constantly, has also experienced mild vaccinia symptoms. This appears to be the first documented "secondary" spread of vaccinia--from the person vaccinated to a close contact, and from that person to a second close contact--since routine vaccination ceased more than 15 years ago.


Although the last U.S. outbreak occurred in 1949, smallpox vaccination remained widespread in the United States through the 1960s. It was discontinued for the general U.S. population in 1972. The last naturally occurring case of smallpox was reported in Somalia in 1977. In 1980, the World Health Organization declared that the disease had been eradicated. Vaccination of military personnel stopped in 1990.

Because of concerns about terrorism after Sept. 11, and the anthrax mailings in Oct. 2001, an advisory committee for the U.S. Department of Health and Human Services recommended that a new vaccination program be put in place for military and health care personnel who might care for possible cases of smallpox. Through this program more than one million people have been vaccinated since 2002.

Direct exposure to vaccinia, a much milder and less contagious virus from the same family as smallpox, can provide strong and lasting immunity against smallpox. Vaccination is performed using live vaccinia virus administered via multiple skin punctures. A bifurcated needle is dipped into the vaccine. Then the vaccine-coated needle is used to make 15 small punctures in the recipient's skin. If the vaccine is a "take," the inoculation site turns red and swollen for three or four days. Then it forms a small vesicle, or blister. By about two weeks, the vesicle dries up, the redness subsides and the lesion forms a crust or scab. By the end of the third week, the scab falls off, leaving a permanent scar that at first is pink in color but eventually becomes flesh-colored.

Studies completed in the 1960s, before widespread vaccination was discontinued, found that most people have either no symptoms or mild side effects such as fever or headaches when exposed to vaccinia during vaccination. For some people, such as those who have skin conditions such as eczema, or those with weakened immune systems, this mild virus can cause rash, fever, and head and body aches. About one in 1,000 people will have a serious reaction. An estimated 14 to 52 out of a million have life-threatening reactions--such as this child.

Public Health Issues

Because of the rash, when caregivers at the Comer Children's Hospital first saw this child they immediately suspected that he had a severe, potentially transmissible, viral infection. They have taken extensive precautions to prevent the spread of vaccinia to health care workers and other patients from the moment he arrived. Both the child and his mother have remained in contact and airborne isolation in a "negative-pressure" room since admission. (They share one room.)

Soon after his admission, public health authorities, including the Chicago Department of Health, the Illinois Department of Health, the Indiana State Department of Health, and the Centers for Disease Control and Prevention (CDC), were notified. Staff involved in this child's care were informed about how the disease is transmitted and told what to do if they develop signs or symptoms consistent with possible vaccinia infection.

Although the risk of the virus infecting anyone else is extremely low, infection-control practitioners at the University of Chicago Medical Center and at St. Catherine's Hospital, have carefully documented all staff contacts with the child and his mother. Staff from the Centers for Disease Control have contacted people from the community who may have been exposed to the father or child prior to March 3. No additional cases have occurred.

Treatment and Recovery

Multiple critical care, infectious disease, and dermatology specialists, as well as many dedicated nurses, have cared for the child and his mother at Comer Children's Hospital. The child and his mother were treated with vaccinia immune globulin (VIG, supplied by the CDC via the Strategic National Stockpile), the first-line therapy for a vaccinia infection. He was also given an anti-viral drug called cidofovir, as well as an investigational anti-viral medication known as ST-246, that may inhibit viral replication.

Both the mother and child have experienced considerable discomfort. The child required, and continues to need, extensive supportive care, including skin care and placement on a ventilator to help him breathe. He began to improve by Monday, March 12, but remains (March 15) in an intensive care unit

There is limited information on long-term consequences of eczema vaccinatum. His caregivers hope for a complete recovery.