The finding are the first to link individual differences written into the genetic code with a vaccine-related complication – albeit a mild one. Most of the eight genetic alterations the scientists identified increased the likelihood of fever after smallpox vaccination. A few, however, reduced fever risk. The study’s results raise the possibility the same genetic variations may also influence fever risk after other live-virus vaccines, including the one for measles, mumps and rubella. This so-called MMR vaccine is routinely administered to small children, and fever is a bothersome and common side effect.
Eventually, the authors say, it may be possible to develop a test that predicts which patients are at risk for vaccine-related fevers. Such a test also may help doctors anticipate and prevent more serious complications linked to the vaccines. Fevers related to vaccines are not considered a serious medical issue, but in rare cases they can lead to more severe complications. Individuals who get a fever after the smallpox vaccine occasionally develop myopericarditis, a potentially life-threatening inflammation of the heart muscle or sac surrounding the heart.
The Washington University scientists studied the occurrence of fever in 346 individuals who had participated in previous smallpox vaccination clinical trials. Records showed that 94 developed fever after vaccination – 61 who received the vaccine for the first time and 33 who had been vaccinated before. The 252 individuals who did not develop fevers after vaccination served as the control group.
The research team found that variations in the IL-1 gene complex on chromosome 2 were most closely linked to an increased risk of fever. Additionally, several variations in the IL-18 gene on chromosome 11 increased fever risk, while one decreased the likelihood of fever.
MEDICA.de; Source: Washington University School of Medicine