Smallpox infection, risk

In the majority of cases, smallpox is spread from one person to another by infected saliva droplets that expose a susceptible person having face-to-face contact with the ill person. People with smallpox are most infectious during the first week of illness, because that is when the largest amount of virus is present in saliva. However, some risk of transmission lasts until all scabs have fallen off. 

At present, vaccines are available for several serious viral infections, including polio, smallpox, rabies, measles, mumps, rubella, hepatitis A and B, and influenza. In some situations, vaccination against certain viral infections is routine. For instance, schoolchildren must periodically show evidence of polio, measles, and other vaccinations according to state and local laws. In other cases, vaccines are administered prior to potential exposure to the virus or in high-risk groups. Influenza vaccinations, for example, are often administered to elderly and debilitated patients during seasonal influenza outbreaks.75,109... 

If faced with a high-risk case, or in a limited smallpox outbreak, physicians should take immediate action to alert infection control at the hospital and institute contact precautions and respiratory isolation. These include (25) ... 

Patients having a febrile prodrome and either one other major criterion or at least four minor criteria are at moderate risk for smallpox. For patients at moderate risk, physicians should alert infection control and immediately institute contact precautions and respiratory isolation. If possible, they should obtain dermatology and/or infectious disease consultation and obtain digital photographs of the lesions. Given a moderate risk situation, the appropriate clinical diagnosis is essential, and physicians must rule out varicella or complication of vaccinia (smallpox vaccine). Therefore, for moderate risk patients, the history is essential, specifically the history of clinical varicella infection, history of vaccination for varicella and history of possible exposure to vaccinia (smallpox) vaccine. 

After an aerosol release of smallpox, public health authorities will make vaccine supplies available to affected communities. Postexposure vaccination is effective in preventing infection or lowering mortality up to 4 days after exposure. Physicians should give the vaccine to suspected cases to ensure that a mistaken diagnosis does not place patients at risk for smallpox. An emergency vaccination program should also include (26) ... 

The virus that causes smallpox. Variola major, is a Category A biological threat agent (CDC 2007). It is a double-stranded DNA orthopoxvirus. It is a widely held opinion among infectious disease professionals that, historically, smallpox has been responsible for more deaths than all other infectious diseases combined. After aggressive efforts by the World Health Organization to immunize the world s population, and because the virus is unable to survive for more than a week outside of its only host, humans. Variola was declared eradicated in 1980 (Murray et al. 2005). The smallpox vaccine can prevent or lessen the severity of the disease if administered within 96 h of exposure. The duration of effectiveness of the vaccine used to eradicate smallpox is not known, and there are reported mild to life-threatening risks are associated with the vaccine. Once a victim is symptomatic, medications and intravenous fluid can be administered to make the patient more comfortable, but there are no antivirals available for unvaccinated infected individuals (Henderson et al. 1999). 

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