Vaccine, killed virus

An example of the use of an attenuated virus is the administration of the measles vaccine to an individual who has not had measles. The m easles (rubeola) vaccine contains the live, attenuated measles virus. The individual receiving the vaccine develops a mild or modified measles infection, which then produces immunity against the rubeola virus. The measles vaccine protects 95% of the recipients for several years or, for some individuals, for life. An example of a killed virus used for immunization is the cholera vaccine. This vaccine protects those who receive the vacdne for about 3 to 6 months. 

Patients with active malignant disease may receive killed vaccines or toxoids but should not be given live vaccines. Live virus vaccines may be administered to persons with leukemia who have not received chemotherapy for at least 3 months. 

Several other diseases exist which can destroy the myelin sheath. Many are a result of viral infections or the body s immune response to a bacterial infection. Guillain-Barre syndrome causes numbness and paralysis starting at the extremities radiating into the trunk of the body where it can cause complete respiratory collapse. Guillain-Barre has occurred in senior citizens who have been given flu vaccinations. The virus used in the vaccination may be attenuated (diminished in virility but not "killed") and still be capable of causing an infection. 

The original polio vaccine was developed by Jonas Salk (for whom the Salk Institute in LaJolla is named). It is a "killed" virus. However, over the years it was found that this did not always impart a complete immunity. The Sabin vaccine contains an attenuated virus. It is interesting to note that the Sabin vaccine can cause an active infection in a rare number of cases. 

Proteins derived from viral coats are as effective in priming an immune system as is the killed virus more traditionally used for vaccines, and are safer first developed was the vaccine for hepatitis B. 

Jonas Salk (1915-1995) begins testing a polio vaccine comprised of a mixture of killed viruses. 

Several clinical studies have been conducted with oral influenza vaccines (Avtushenko et al. 1996 Lazzell et al. 1984). These include water in oil emulsion form of inactivated virus vaccine and an enteric-coated killed virus vaccine. Although these vaccines induced IgA responses, there were inadequate levels of virus-neutralizing IgG antibodies in the serum to fulfil regulatory requirements for vaccine immunogenicity. This warrants refinement and further development of these types of vaccines. 

Langhans B, Schweitzer S, Nischalke HD, Braunschweiger I, Sauerbruch T, Spengler U (2004) Hepatitis C virus-derived lipopeptides differentially induce epitope-specific immune responses in vitro. J Infect Dis 189(2) 248-253 Lazzell V, Waldman RH, Rose C, Khakoo R, Jacknowitz A, Howard S (1984) Immunization against influenza in humans using an oral enteric-coated killed virus-vaccine. J Biol Standard 12(3) 315-321... 

Polio is the only disease, at present, for which both live and killed vaccines compete. Since the introduction of the killed virus (Salk) in 1956 and the live attenuated virus (Sabin) in 1962 there has been a remarkable decline in the incidence of poliomyelitis (Fig. 9.1). The inactivated polio vaccine (IPV) contains formalin-killed poliovirus of all three serotypes. On injection, the vaccine stimulates the production of antibodies of the IgM and IgG class that neutralize the virus in the second stage of infection. A course of three injections at monthly intervals produces long-lasting immunity to all three poliovirus types. 

Killed vaccines. Killed vaccines are suspensions of bacteria, viruses or other pathogenic agents, that have been killed by heat or by disinfectants such as phenol, ethanol or formaldehyde. Killed microorganisms obviously cannot replicate and cause an infection and so it is necessary for each dose of a killed vaccine to contain sufficient antigenic material to stimulate a protective immune response. Killed vaccines therefore usually have to be relatively concentrated suspensions. Even so, such preparations are often rather poorly protective, possibly because of partial destruction of protective antigens during the killing process or inadequate expression... 

Vaccination against viruses, such as influenza and measles, commonly involves parenteral (subcutaneous or intramuscular) administration of a live, attenuated virus or a killed virus. The inhalation route is being examined as a means of immunizing patients because it circumvents logistical problems associated with parenteral administration, such as needle sterility issues, patient aversion to needles, and the need for administration by a health care professional. In very young children, maternally derived IgG antibodies may prevent successful immunization [118]. The inhalation route may allow vaccination of these children because the immunological response of the airways is less likely to be influenced by maternal antibodies [118], Aerosol immunization has been shown to be effective against measles [119] and, in some respects, is more efficacious than parenteral immunization [120],... 

Formaldehyde is useful in the production of killed virus vaccines. A deadly virus, such as polio virus, can be treated with heat and formaldehyde. Formaldehyde reacts with the genetic information (RNA) of the virus, damaging it irreparably. It also reacts with the virus proteins but does not change their shape. Thus when you are injected with the Salk killed polio vacdne, the virus can t replicate and harm you. Flowever, it will be recognized by your immune system, which wiU produce antibodies that will protect you against poUo virus infection. 

PoUo vaccine ([onas Salk) Salk s polio vaccine, which uses the killed virus, saves lives and improves the quality of life for millions afflicted by polio. 

Figure 2. Adjuvant effect of poly(ICLC) in monkeys receiving heat killed virus vaccine vs Venezuelan Equine Encephalitis Virus.

Their frequency is higher than in the general population. They can be community-acquired infections or caused by opportunistic microbes, therefore vaccines without live virus, using either attenuated or killed virus, are recommended. 

Vaccine A suspension of attenuated or killed bacteria or virus, or portions thereof, injected to produce active immunity. 

Viral vaccines present problems of safety testing far more complex than those experienced with bacterial vaccines. With killed viral vaccines the potential hazards are those due to incomplete virus inactivation and the consequent presence of residual live virus in the preparation. The tests used to detect such live virus consist of the inoculation of susceptible tissue cultures and of susceptible animals. The cultures are examined for cytopathic effects and the animals for symptoms of disease and histological evidence of infection at autopsy. This test is of particular importance in inactivated poliomyelitis vaccine, the vaccine being injected intraspinally into monkeys. At autopsy, sections of brain and spinal cord are examined microscopically for the histological lesions indicative of proliferating poliovirus. 

Vaccination to induce an adaptive immune response is expected for a broad range of infectious diseases and cancers. Traditional vaccines are mainly composed of live attenuated viruses, whole inactivated pathogens, or inactivated bacterial toxins. In general, these approaches have been successful for developing vaccines that can induce an immune response based on antigen-specific antibody and cytotoxic T lymphocyte (CTL) responses, which kill host cells infected with intracellular organisms (Fig. 1) [1,2], One of the most important current issues in vaccinology is the need for new adjuvants (immunostimulants) and delivery systems. Many of the vaccines currently in development are based on purified subunits, recombinant... 

Responses to live and killed vaccines generally are suboptimal for human immunodeficiency virus (HlV)-infected patients and decrease as the disease progresses. 

Vaccine A preparation of killed or weakened infective or toxic agent used as an inoculation to produce active artificial immunity that is, a suspension of live (usually attenutated) or inactivated microorganisms (e.g., bacteria, virus, or rickettsiae) administered to induce immunity and prevent infectious disease. 

Killed vaccines are made by growing bacteria or virus and then treating it with heat and/or chemicals (usually formalin). These vaccines cannot cause disease from infection, even in someone with a weakened immune system. 

There are two classical strategies for vaccination. One involves vaccination with either killed pathogenic organisms or subunits of the pathogenic organism. The other utilizes live attenuated viruses or bacteria that do not cause disease but have been derived from the pathogenic parent organism. 

Virus Submicroscopic organism that causes infectious disease. In cancer therapy, some viruses may be made into vaccines that help the body build an immune response to, and kill, tumor cells, [nih]... 

In 1976, another vaccine case illustrated how dangerous a mistake involving vaccines can be. Between October 1,1976 and December 14,1976, more than 40 million people were vaccinated against swine flu (a virus similar to fhe 1918 Spanish flu virus fhaf killed so many during World War I). The feared epidemic never manifested, buf fhere was a tenfold increase in CBS (in which fhe body s immune system attacks its peripheral nerves), which thousands of people confracfed. 

Examples of killed or inactivated vaccines are cholera vaccine containing dead strains of Vibrio cholerae, hepatitis A vaccine with inactivated hepatitis A virus, pertussis vaccine with killed strains of Bordetella pertussis, typhoid vaccine with killed Salmonella typhi, and influenza vaccine with various strains of inactivated influenza viruses (see Exhibit 4.2 for a discussion of influenza viruses and vaccines and Exhibit 4.3 on avian influenza H5N1). 

---