Post-eradication Vaccination
The vaccine consists of the virus which causes the related, yet far milder, cowpox disease; this virus is named vaccinia (the term vaccine is derived from it), from the Latin vacca which means cow. This vaccine has functional viruses in it which improves its effectiveness but causes serious complications for people with impaired immune systems (for example chemotherapy and AIDS patients, and people with eczema) and is not yet considered safe for pregnant women. A woman planning on conceiving within one month should not receive the smallpox immunization until after the pregnancy. In the event of an outbreak the woman should delay pregnancy if possible. A small, yet significant, percentage of healthy individuals also suffer adverse side-effects which, in rare cases, include permanent neurological damage. Vaccines that only contain attenuated vaccinia viruses (an attenuated virus is one in which the pathogenicity has been decreased through serial passage) have been proposed but some researchers have questioned the possible effectiveness of such a vaccine. According to the Centers for Disease Control and Prevention (CDC), "vaccination within 3 days of exposure will prevent or significantly lessen the severity of smallpox symptoms in the vast majority of people. Vaccination 4 to 7 days after exposure likely offers some protection from disease or may modify the severity of disease." This, along with vaccinations of so-called first-responders, is the current plan of action being devised by the United States Department of Homeland Security (including Federal Emergency Management Agency (FEMA), now part of DHS) in the United States.
The vaccine can cause complications for those around those who are vaccinated. People who get the vaccine will shed virus particles through vesicles on their skin and possibly through their respiratory tract. Infections in close and not-so-close contacts can ensue. The current plan to vaccinate first responders has the potential to cause infection in the most vulnerable section of the population, the hospitalized ill. Family contacts are also susceptible, although they are less vulnerable because their immune systems are presumably intact. Secondary infection can cause skin disease, pulmonary disease and rarely, neurologic disease.
As of June 21, 2003, a scientific advisory panel had issued a recommendation against further vaccination of first responders because a significant number of those vaccinated suffered heart problems, notably pericarditis and myocarditis.
In May 2007, the Vaccines and Related Biological Products Advisory Committee of the U.S. Food and Drug Administration (FDA) voted unanimously that a new live virus vaccine produced by Acambis, ACAM2000, is both safe and effective for use in persons at high risk of exposure to smallpox virus. However, due to the high rate of serious adverse effects, the vaccine will only be made available to the CDC (a part of the United States Department of Health and Human Services) for the Strategic National Stockpile.
The main problem with developing a new, safer vaccine, is that, barring a bioterrorist attack on immunized individuals, its effectiveness cannot be tested on humans, and other animals do not naturally contract smallpox. Monkeys at USAMRIID research facilities have been infected, but tests on animals that are artificially infected with a human disease may give false or misleading results. To demonstrate safety and effectiveness, human trials always have to confirm data obtained from animal testing.
In the United States the smallpox vaccine is the only FDA-approved treatment for smallpox and monkeypox. As with smallpox, vaccination after infection is effective if the vaccine is given before symptoms develop.
Currently, the United States Air Force has made it mandatory that any Airman deploying to the Middle East must receive the smallpox vaccination before leaving stateside. The same is true of the U.S. Army, and any US Marine being deployed outside the contiguous United States (OCONUS), as well as any Marine or US Navy sailor being deployed ship side. It is also an option for all Department of Defense employees and contractors traveling to the United States Central Command's Area of Responsibility (CENTCOM AOR).
Read more about this topic: Smallpox Vaccine