WASHINGTON (Reuters) - The 2-year-old son of a soldier deployed to Iraq is in critical condition after developing a reaction to his father’s smallpox vaccination, the U.S. Centers for Disease Control and Prevention said on Saturday.
The child, being treated in a Chicago hospital, has a rare but very serious reaction to the vaccination site called Eczema vaccinatum, the CDC said. It is the first such case since vaccination against smallpox resumed in 2002, said CDC pox virus expert Dr. Inger Damon.
The toddler’s father is a soldier vaccinated while on deployment to Iraq. The father was unexpectedly furloughed and evidently his wife and son touched the vaccine site and became infected, the CDC said.
“They can get a particularly noxious and sometimes fatal rash,” Damon said in a telephone interview.
The smallpox vaccine is made using a closely related virus called vaccinia. It is scratched into the surface of the skin, where it causes a mild infection that makes people much less susceptible to smallpox.
But because it uses a live virus, the vaccine can cause severe and sometimes deadly side effects. Eczema vaccinatum is one of them, although this is the first case to be reported since smallpox vaccinations resumed in the United States in 2002.
“The child is a dependent of a U.S. Army Service member deploying to Iraq,” the CDC said in a statement.
“We don’t know what the soldier’s reaction was like at his vaccination but he is doing well now and hasn’t described any illness that we are aware of,” Damon said.
The child has been treated with immune globulin, an antiviral drug called cidofovir, and an experimental antiviral made by Siga Technologies called SIGA-246, Damon said.
“We are cautiously optimistic that the child is improving,” Damon said.
Between 1959 and 1968, when smallpox vaccination was common, 12 cases of Eczema vaccinatum were reported in the United States, with an 18 percent fatality rate.
The smallpox virus once killed 30 percent of its victims, leaving many others disfigured. A global vaccination campaign eradicated the disease in 1979.
But some samples of the virus remained in government freezers and experts believe it could be used as a biological weapon. The United States resumed vaccinating some people in 2002, including 40,000 civilian health workers and hundreds of thousands of military personnel.
Many civilians resisted getting inoculated because of the vaccine’s notorious side effects. But the CDC has reported only two very severe cases, both involving heart conditions that potentially could have been caused by the vaccine.
Damon said a stringent screening program had made vaccination safer than in years past. Anyone predisposed to side effects, such as people known to have eczema, are not supposed to get the shot.
“So I think this is one of those unfortunate events where a family member who was at risk from vaccinia ends up coming in contact with a vaccinated individual,” she said.