Smallpox: What You Need To Know

Man with smallpox. Public Health Images Library (PHIL) id# 131. Source: CDC/Barbra Rice

Smallpox is a category A biological disease that in the wrong hands could easily become a biological weapon of mass destruction. A single case of smallpox would be considered an emergency caused by intentional release as the disease was confirmed eradicated in December 1979. An accidental release of the virus should be contained within the facility where the release occurred and conditions within these facilities allow for the initial treatment of anyone exposed within the facility.

For these reasons a member of the public being diagnosed with smallpox, will under international agreement, be considered an act of terrorism.

The last case of smallpox was recorded in September 1978, in Birmingham UK when Janet Parker, a medical photographer, contracted the disease via an accidental release at Birmingham Medical School. Janet died on September 11th 1978, though her mother, whom she had infected, survived.

The smallpox virus, medically called Variola is still in existence in  labs in the USA and  Russia. Governments around the world confirm that they hold 90 million doses of smallpox vaccine and the seed virus from which new vaccines can be made. Vaccinia virus strain Lister Elstree is stored in level four containment in Bilthoven, Netherlands.

The vaccines stored will be in various stages of degradation and will at some point need replacing. Tests on the vaccines are done every five years to check the efficacy of the drugs, so far vaccines up to 18 years old would still be effective if used.

As with all vaccines complications can occur and the death rate from smallpox vaccine was estimated to be one per million. Those vaccinated many years ago against smallpox may still have a small amount of immunity, possibly enough to prevent death, but not enough t prevent them catching the disease and many of the complications that go with it. These include:

* arthritis and bone infection
* encephalitis
* eye infections
* blindness
* pneumonia
* scarring
* severe bleeding
* skin infections

It is recommended that smallpox inoculations be repeated every 10 years in non-endemic regions and every 3 years in regions where the disease was endemic.

There are two types, and two sub-types of smallpox. Variola Minor as the name suggests is the least problematic and has a death rate of around 1% of those infected. Variola Major has a death rate of around 30% and two sub-types of Variola Major, haemorrhagic and malignant smallpox, although very, very rare have a death rate of almost 100%.

Smallpox is spread by face to face contact, on clothes and bedding or via aerosolised particles. In lab experiments 90% of the smallpox virus was found to be dead 24 hours after release into a contained atmosphere. Sunlight and heat hastens the demise of the virus.

Due to its long incubation period of 7-17 days, with a mean of 12-14 days smallpox can be in the community for a few days before it is realised there has been a release of the disease. Like many illnesses in the first instance it manifests as would a bad case of flu. The symptoms are:

* general malaise
* fatigue
* headache progressing to severe headache
* fever progressing to high fever
* vomiting
* diarrhoea
* excessive bleeding
* raised pink rash that becomes crusty

Because of the long incubation period epidemics get off to a relatively slow start when compared to most diseases. New waves of victims will occur every 2-3 weeks and the disease will progressively move through a region until there are no hosts left. The last smallpox vaccinations were given to children in 1979 and we are approaching the time when very few on the planet will have even residual immunity. Only those considered to be at risk from smallpox are offered inoculation, currently this is restricted to lab workers who come into contact with the virus. In any outbreak medical workers and the military will be first in line to receive any vaccine on offer.

Monkeypox is also a Variola virus and it has the same symptoms as smallpox though they are much less severe. 1-10% of those contracting monkeypox will die from it. Smallpox vaccine is effective against the Monkeypox virus.

Caring for someone with Variola carries risks of contracting the disease. Strict barrier nursing should be employed and only one person should come into direct contact with the patient. All clothing towels and bedding should be stored in a hard environment such as a lidded bucket for five days to make sure the virus is dead. The items should then be washed in hot water and detergent. Formaldehyde gas was used for the fumigation of homes where smallpox was present decades ago but there is no current advise or protocol in place at this point due to the total eradication of the disease.

There is nothing except inoculation that prevents smallpox and inoculation up to day four after being in contact with the disease can still reduce the severity of the condition. No government has so far gone on record to say how long it would take them to mass produce enough vaccine to inoculate the population of their country. With 90 million vaccine doses in store worldwide, and making a logical assumption that some of them will have degraded since their production lets hope for all our sakes that it doesn’t take them too long.

Take care

Liz