The story of smallpox is one of modern medicine’s most successful public health campaigns. It is one of the only infectious diseases completely eradicated due to worldwide vaccination programs. There has not been a naturally occurring documented case since October 26, 1977 and the global eradication of smallpox was officially announced in 1979.
In 1980, the World Health Organization recommended that all countries stop their vaccination program.
The history of the smallpox virus is interesting. The Variola virus causing smallpox is in the orthopox virus family, which also includes cowpox and monkeypox. It plagued Europe and Asia for centuries, and when European explorers ventured to the New World, it nearly decimated the Native American population. In 1796 an English scientist Edward Jenner, who is credited as the pioneer of the smallpox vaccine, discovered that milkmaids who had been exposed to the cowpox virus, if or when they were infected with the smallpox virus, contracted a much milder form of the disease.
Jenner then postulated that cowpox infection gave some immunity to smallpox. He tested his theory by inoculating a young boy, James Phipps with a milder cowpox virus collected from the cowpox pustules of a milkmaid. Then, he exposed the boy to smallpox infected material called variolation; this type of experimentation aimed to prove immunity, however it often resulted in contracting the disease and sometimes death. In this case, Phipps did not get sick from the exposure.
This vaccination was eventually accepted as safer way to confer immunity; yet in 1840 variolation, the use of smallpox itself to confer immunity, was banned. The word vaccine finds its root in the Latin word for cow, vacca.
The Variola virus only infects humans and is spread by human-to-human contact, and is especially damaging to children and pregnant women. Smallpox disease has a high mortality rate, killing about 1/3 or 30% of people infected with the Variola virus. The virus is inhaled; once in the lungs, it multiplies and spreads via the bloodstream to the skin, intestines, kidneys and brain. Symptoms including fever chills, nausea, vomiting, headache and backache begin about 1 week after exposure.
In the skin it creates a rash that forms a blister and pus filled, pimple-like sores called pustules. The rash appears about 2 weeks after infection, and at this point, the patient is highly contagious. The rash looks similar to the chickenpox rash, but chickenpox rash can occur in different stages of development –new blisters can appear while others have pustules and still others are healing and scabbing.
Conversely, the smallpox rash is always in a uniform stage. First, blisters appear before maturing to postules. Those that do survive will have horribly deep scarring of the skin. The virus also causes lesions that start in the mouth and then spread to the face, arms, legs and torso.
Chickenpox progresses from the arms and legs to the torso and is rarely seen on the palms, soles of the feet, armpits or elbows.
Because smallpox is both highly contagious and fatal, it could be a devastating bioterrorist weapon. In fact, the first the documented use of smallpox as a weapon was during the French and Indian Wars in the mid-1700s. The Native Americans fought with the French against the British in North America. The British deliberately distributed blankets used by smallpox victims hoping to infect the unexposed Native Indians. (Live virus particles can remain on clothing and bedding and surfaces for up to a week.) This early “biological weapon” caused an epidemic that killed almost 50% of the affected tribes.
Smallpox is a dangerous bio-weapon because it is easily spread and aerosolized; only about 10-100 virus particles can infect someone. The virus is hard to diagnose in its early stages and, like many viral infections, there are no drugs or treatments that kill it. At least 30% of unprotected people can become infected and die. Since mass vaccination programs stopped in 1980 and most people only have a 10-year immunity without a booster, it’s estimated that about 42% of the US population today is under 30 years old and has never been vaccinated.
Supposedly there are only two laboratories in the world that have the smallpox virus: the Center of Disease Control and Prevention in Atlanta, Georgia and the State Research Center of Virology and Biotechnology in Koltsovo, Russia. But the existence of a stockpile in other countries is really unknown.
But all is not bleak, emergency physicians and emergency departments are trained to recognize and immediately respond to this potential Biosafety Level IV. They coordinate with public health officials on both local and federal levels to isolate and quarantine any suspected cases, as well activate the stockpiles of available vaccinations to contain any potential spread.
Vaccination within 4-5 days of getting exposed may not totally prevent the disease, but it will lessen the severity of it and certainly lower the risk of death. Our national stockpile is now comprised of a newer modern smallpox vaccine with potentially less side effects. Additionally, there is ongoing research to develop antiviral drugs and immunotherapy to kill the virus and treat the disease.
Rest assured that these efforts, and an increased general awareness, will certainly help to mitigate any possible attack that may happen here in the US.