By Dr. Richard Rupp and Bridget Hawkins, Ph.D.
In a previous column we answered a high school student’s question about a vaccine scar she has on her arm. We stated the BCG vaccine and the smallpox vaccine were likely the cause a scar on the upper arm. The likely cause in the student’s case is the BCG vaccine because the student was foreign-born and the smallpox vaccine is no longer routinely given in the United States. A reader called to let us know that some members of our military still get the smallpox vaccine.
We want to thank the reader for taking time to contact us. We are aware that the military and researchers working with related poxviruses still receive the smallpox vaccine. We were writing about the general public when we said that the smallpox vaccine is no longer routinely given here. However, the reader’s comment is reason enough to tell you more about smallpox.
It’s a horrible disease killing about 30 percent of unvaccinated individuals. The initial symptoms are similar to many common viral infections and include fever, muscle pains, headache and fatigue. Nausea, vomiting and back pain are frequent symptoms as well. After about four days, the infected person begins to feel better and red spots start to appear in the mouth and over most of the body. The red spots develop into bumps that fill with pus-like fluid and then scab over. This rash lasts about three weeks and can cause disfiguring scars. Blindness may result if scarring occurs on the eyes. There is no specific drug treatment for smallpox at this time.
The smallpox virus is spread by droplets from the mouth or nose. A person usually has to be within six feet of an infected person to catch the disease. Smallpox can also spread through contact with infected body fluids or contaminated items such as bedding or clothing.
Vaccination has eliminated natural cases of smallpox. The last natural case of smallpox was in Somalia in 1977. The World Health Organization authorized only the Russian Federation and the U.S. to keep samples of the smallpox virus. The samples are solely for scientific study. Unfortunately, other countries and groups may possess the virus as well.
People who survive smallpox won’t get the disease again, but protection from vaccination wanes over time. People who got a smallpox vaccine before 1986, the end of global routine vaccination, are no longer protected. That leaves most of the world’s population unprotected because the majority have never had the disease, were never vaccinated or were vaccinated a long time ago.
This vulnerability of the population coupled with the features of the disease makes smallpox an ideal bioweapon. Upon its release, smallpox would spread quickly among the general population, tying up resources and bringing much of our infrastructure to a halt. The threat of such an attack is low but the consequences would be horrendous.
In response to this potential threat, some of our military forces, emergency-essential civilians and mission-essential contractors are vaccinated against smallpox. This allows them to respond in case of an outbreak and carry out critical military missions. This also serves as a deterrent to such attacks. Forces who serve in South Korea and other troubled regions of the world such as Afghanistan and the Middle East receive the smallpox vaccine. Between December 2002 and January 2008, more than 1.4 million men and women in uniform got the vaccine.
Why don’t we restart routine smallpox vaccination? It is because of the risk-benefit ratio. The benefit is considered very low because an attack is very unlikely. Although considered safe, there are real risks associated with smallpox vaccination. In the past when vaccinating the general population, between 14 and 52 people out of every 1,000,000 vaccinated for the first time experienced potentially life-threatening reactions. One to two of them would die. That level of risk is felt to be too high when the benefit is so low.
The current strategy against smallpox is to vaccinate our service members. Being vaccinated against smallpox is yet another sacrifice our armed forces make in protecting us all. It is yet another reason, on a long list, to thank the military and first responders for their service.
Dr. Richard Rupp is a pediatrician and member of UTMB’s Sealy Center for Vaccine Development. Bridget Hawkins, Ph.D., is the assistant director of the Sealy Center for Vaccine Development. This column is supported by a UTMB President’s Cabinet Award to provide information about vaccines. Visit www.utmb.edu/scvd/vaccinesmarts for more information.