Smallpox control

A live vaccine strain of measles (Chapter 15) was introduced in the USA in 1962 and to the UK in 1968. A single injection produces high-level immunity in over 95% of recipients. Moreover, since the vaccine induces immunity more rapidly than the natural infection, it may be used to control the impact of measles outbreaks. The measles virus cannot survive outside ofan infected host. Widespread use ofthe vaccine therefore has the potential, as with smallpox, of eliminating the disease worldwide. Mass immunization has reduced the incidence of measles to almost nil, although a 15-fold increase in the incidence was noted in the USA between 1989 and 1991 because of poor compliance. 

The application of vaccine technology forms a core element of modern medicinal endeavour. It plays a central role in both human and veterinary medicine and represents the only commonly employed prophylactic (i.e. preventative) approach undertaken to control many infectious diseases. The current (annual) global vaccine market stands at in excess of US 3 billion. Immunization programmes, particularly those undertaken on a multinational scale, have served to reduce dramatically the incidence of many killer/disabling diseases, such as smallpox, polio and tuberculosis. 

There is no proven treatment for smallpox, but in persons exposed to smallpox who do not show symptoms as yet, the vaccine — if given within four days after exposure — can lessen the severity of or even prevent illness. However, once a patient shows symptom, treatment is limited to supportive therapy and antibiotics to treat bacterial infections. Patients with smallpox can benefit from supportive therapy such as intravenous fluids, and medicines to control fever or pain. 

Vaccination against viral and bacterial diseases has been one of the success stories of human and veterinary medicine. Probably the most outstanding example of the effectiveness of vaccination is the eradication of smallpox. In 1967 between 10 and 15 million cases of smallpox occurred annually in some 33 countries. By 1977 the last naturally occurring case was reported in Somalia. Polio, too, has been controlled in developed countries, for example the number of cases in the USA was reduced from over 40,000 per year in the early 1950s, before a vaccine was available, to only a handful of cases in the 1980s. Diphtheria is now almost unheard of yet over 45,000... 

The antibody response to yellow fever vaccine was impaired in protein-deficient children with kwashiorkor compared to the well-nourished controls. Polio antibody production was normal in the malnourished children, all of whom also responded in the normal fashion to smallpox vaccination. They had no evidence of disseminated vaccinia (B8). In Guatemala, on the other hand, smallpox vaccination of children who had fully recovered from severe protein-calorie malnutrition led to a drop in their nitrogen retention with the added complication of disseminated vaccinia (V3). 

Three basic approaches are used to control viral diseases vaccination, antiviral chemotherapy, and stimulation of host resistance mechanisms. Vaccination has been used successfully to prevent measles, rubella, mumps, poliomyelitis, yellow fever, smallpox, chickenpox, and hepatitis B. Unfortunately, the usefulness of vaccines appears to be limited when many stereotypes are involved (e.g., rhinoviruses, HIV). Furthermore, vaccines have little or no use once the infection has been established because they cannot prevent the spread of active infections within the host. Passive immunization with human immune globulin, equine antiserum, or antiserum from vaccinated humans can be used to assist the body s own defense mechanisms. Intramuscular preparations of immune globulin may be used to prevent infection following viral exposure and as replacement therapy in individuals with antibody deficiencies. Peak plasma concentrations of intramuscular immune globulins occur in about 2 days. In contrast, intravenously administered immune globulin provides immediate passive immunity. 

The threat of a bioterrorist attack with smallpox is especially disturbing since the eradication of smallpox remains one of the great achievements in human history. Unfortunately, since routine vaccination against smallpox was discontinued in 1978, few people retain immunity today. Although there are only two official repositories of the smallpox virus today, it is still possible that terrorists will be able to obtain the virus. Thus, the government has had to stockpile supplies of the vaccine, and there is some debate about whether to resume routine smallpox vaccinations. Although the smallpox vaccine was discovered by accident, the story of how Louis Pasteur developed the first anthrax vaccine and his use of unvaccinated animals as controls remain as excellent lessons about the process of science (Trachtman 2002). 

Pre-1900 Treatment of rabies, anthrax, and smallpox Principles of infection control and pain relief Management of heart failure... 

Centers for Disease Control and Prevention. (March 25, 2003a). Temporary deferral recommended for heart patients volunteering for smallpox vaccination. Retrieved March 11, 2007 from http //www.bt.cdc.gov/agent/smallpox/vaccination/ heartproblems. asp... 

There is also heightened concern that a bioterrorist could release smallpox, a disease that has been eradicated from the globe since at least 1980. Officially, only two places on Earth still maintain viable smallpox virus in cold storage Novosibirsk, Russia and Atlanta, Georgia, at the Centers for Disease Control and Prevention (CDC). Some unconfirmed reports allege that other countries, however, including North Korea and perhaps others, still hold on to smallpox virus specimens. Could a terrorist release smallpox, and how would it affect a mostly immunologically naive population ... 

Centers for Disease Control and Prevention. (2003). Update Cardiac related events during the civilian smallpox vaccination program—United States, 2003. MMWR Morbidity and Mortality Weekly Report, 52, 492-496. 

Centers for Disease Control and Prevention. (2002, September 16). Smallpox Vaccination Clinic Guide. Retrieved February 27, 2007, from http //www.bt.cdc.gov/agent/smallpox/ vaccination/pdf/smallpox-vax-clinic-guide.pdf Centers for Disease Control and Prevention. (2005, April 14). Strategic National Stockpile. Retrieved February 17, 2007, from http //www.bt.cdc.gOv/stockpile/ synopsis Centers for Disease Control and Prevention. (2007, February 21). Public Health Training Netivork. Retrieved February 27, 2007, from http //www.phppo.cdc.gov/phtn/default.asp... 

Robinson [48] described a gas chromatographic method for measuring residual water in freeze-dried smallpox vaccine in 1972. The method was developed to optimize quality control of a tissue-culture smallpox vaccine. Water is extracted from the sample with benzene and determined by gas chromatography with thermal conductivity (hot wire) detection and columns packed with Chromosorb 102. 

The last case of smallpox occurred in 1977, and the eradication of smallpox was declared complete by the World Health Assembly in 1980. Since then, routine smallpox vaccination has ceased in all countries, because it is no longer required and because serious adverse reactions sometimes occur after both primary vaccination and revaccination (SED-8, 709) (SED-11, 685) (SEDA-1, 247) (SEDA-3, 262) (SEDA-4, 227) (SEDA-6, 289) (SEDA-13, 289) (SEDA-15, 357) (1-5). However, the threat of bioterrorism has made it necessary to consider prevention and control... 

In 1980, the US Public Health Service first recommended the use of Vaccinia (smallpox) vaccine to protect laboratory workers occupationally exposed to orthopoxviruses. In 1991, the Centers for Disease Control, Atlanta, Georgia, published recommendations on Vaccinia vaccine. From 1983 to 1991, 4649 doses of smallpox vaccine were administered, of which 57% were given in 1989-91. The proportion of primary vaccinations increased from 4% in 1983-88 to 14% in 1989-91. Of vaccinees 93% reported no signs or symptoms after vaccination. Reported adverse reactions were mild lymphadenopathy, fever or chills, and tenderness at the site of vaccination. No severe adverse effects were reported. However, one vaccinee reported a spontaneous abortion 5 months after primary vaccination (16). 

Centers for Disease Control and Prevention (CDC). Update adverse events following civilian smallpox vaccination—United States, 2003. MMWR Morb Mortal Wkly Rep 2003 52(34) 819-20. 

On the other hand, we must not forget that the ultimate goal of an immunization program is control of disease or even its regional elimination or worldwide eradication. A successful immunization program can lead to the eradication of disease and opens up the possibility of ultimately abandoning immunization (and with it the occurrence of adverse effects) completely. Smallpox eradication made it possible to stop smallpox immunization and poliomyelitis eradication, which is expected to be achieved within a few years, will mean the end of polio vaccine. 

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