Vaccine

A vaccine, the vaccine or the vaccine called (Latin vaccinus " of cows to arise "; see vaccination ) is a biologically or genetically engineered antigen, usually consisting of protein or genome fragments, killed or attenuated pathogens. The vaccine used in the context of a vaccine for the specific activation of the immune system in terms of a specific pathogen or a group of pathogens.

, The reaction of the immune system is utilized (for example, surface proteins as antigens ) to provoke in the presence of pathogens and their specific parts of the immune response. This leads to the formation of antibodies and specialized T-helper cells, which then provide a long lasting protection against the particular disease, which can depending on the agent between a number of years and continue throughout life.

Origin of vaccines

Smallpox was the first condition in which it was attempted to immunize individuals by deliberate infection with other agents. It is believed that these attempts in India or China already began at either 200 BC. Chinese doctors selected for obtaining the vaccine subjects with mild disease course and distant crustal pieces of smallpox infected this. The pieces were ground to a powder and inserted into the nose of the person to be vaccinated.

Lady Mary Wortley Montagu reported in 1718 that the Turks themselves in a similar manner exposing the body fluids of infected easily, and applied this method to their own children. Observed later than in the years from 1770 six people, including Sevel, Jensen, Jesty (1774 ), Rendall and Plettenberg (1791 ), that milkmaids became immune to smallpox after they had survived the relatively innocuous cowpox. You then inoculated in families and acquaintances successfully with the Kuhpockenlymphe. In 1796 also, the English country doctor Edward Jenner observed during the flowering of European smallpox epidemics that maids were partially infected by contact with cow udders with cowpox, which are a comparatively harmless relative of the smallpox. He took infectious fluids from the hand of the infected in this way maid Sarah Nelmes, and led them by injection or scratching into the arm of the eight- year-old, healthy James Phipps. James developed symptoms of cowpox infection, from which he recovered completely. 48 days later, Jenner injected him with smallpox contaminated (contaminated ) matter. The boy did not develop any symptoms.

Live attenuated vaccine

Such live vaccines contain attenuated ( attenuated ) viruses or bacteria that can still multiply and trigger an immune response, but usually not a disease. A live attenuated vaccine is significantly more effective than inactivated vaccine in general.

In rare cases, it may on the application of such a vaccine come to a mutation in the direction of non-attenuated output form in the possible proliferation of micro then it can enter the disease by the. Examples are discontinued in Europe oral polio vaccine, which has very rarely triggered the Impfpoliomyelitis, the MMR vaccine, the Bacille Calmette -Guérin as well as vaccines against yellow fever. For typhoid vaccination both live as well as inactivated vaccines are available.

Live vaccines are divided into

• Cold-adapted strains can multiply at temperatures of around 25 ° C, which limits the virus to the upper respiratory tract, and
• Temperature- sensitive strains, the replication of which is limited to a temperature range of 38-39 ° C; It is not here for infection of the lower respiratory tract.

Inactivated vaccine

Inactivated vaccines contain inactivated or killed viruses or bacteria or components of viruses, bacteria or toxins. These can be in the body not reproduce more or poison him, as it could be the tetanospasmin, but they also trigger an immune response ( immune reaction). Examples are the toxoid vaccines and vaccines against influenza, cholera, bubonic plague, hepatitis A or hepatitis B.

Inactivated vaccines are divided into:

• Toxoids: toxoids are detoxified toxins of pathogenic microorganisms. These vaccines can be used in cases where the pathogen does not cause itself, but as with tetanus and diphtheria toxins, especially their disease symptoms.
• Inactivated whole particle vaccines: inactivation of viruses by means of a combined use of formaldehyde, beta- propiolactone and psoralen
• Part particle vaccines: the destruction of the virus surface with detergents or strong organic solvents.
• Subunit vaccines or vaccine gap: the surface is fully dissolved and specific components ( hemagglutinin and neuraminidase proteins) out purified. Another possibility is to make the subunits recombinantly. Subunit vaccines are poorly immunogenic, but have this little side effects.

Advantages and disadvantages of live and inactivated vaccines -

Live vaccines are more effective than inactivated vaccines because they induce in addition to humoral immunity ( one caused by circulating antibodies in the body fluids form of immunity ) and to life- long-lasting cellular immune responses.

However, they are slightly inferior in compatibility and which carry a very small risk of reversion into pathogens and thus the triggering of a (usually attenuated ) form of the disease against which they were originally intended to protect.

Furthermore, live-virus vaccines from three months before and throughout pregnancy are contraindicated according to current recommendations of the competent in Germany Robert Koch Institute. In contrast, vaccination with inactivated vaccines due to be administered to pregnant women during the second and third trimester of pregnancy without hesitation; in the first third should to exclude any risk for the child, however, only those Totstoff vaccinations be made which are individually strongly indicated. In the subsequent lactation vaccinations are generally possible without restrictions.

Different live vaccines may be administered simultaneously, without any problems. At non simultaneous vaccination of the distance between two live vaccines, however, is to be at least four weeks. Inactivated vaccines or a combination of them does not affect this.

Other

A number of other, partly experimental techniques are used in the course of a vaccine designs:

• Conjugated vaccines: some bacteria have polysaccharide outer shells that provoke only weak immune responses. By connecting the outer shells with proteins ( such as toxins ) can be made to the immune system to recognize the polysaccharides, such as protein antigens.
• Rather than fully attenuated or inactive pathogens can also fragments ( ie fragments ) an immune response provoked.
• Recombinant vectors: The combination of the physiology of the microorganism with the DNA of another pathogen immunity against infection with complex processes can be provided.
• DNA vaccination: In recent years, was a new form of vaccination, based on the DNA of the agent. Here, viral or bacterial DNA is inserted and expressed in the host organism. Thus an immune response is effected. Here, according to current state of research accounts ( 2005), the side effects of conventional vaccination methods. However, a risk is the incorporation into the genetic material; This can be avoided by the use of mRNA.
• MRNA vaccine: Similar DNA vaccination genetic code is used, but in the form of the mRNA of the respective antigen. The advantage is the stability with respect to DNA. mRNA can be administered intranasally in the simplest case, ie must not be injected. Various methods for intensification of the immune response have already been tried, for example, the complexation with protamine. Areas of application has so far been mainly the treatment of cancer and infection prophylaxis.

Economic importance

The vaccine production experienced in the face of the threat posed by pathogens, such as avian flu " H5N1 " flu and swine flu " H1N1", as well as in the veterinary field bluetongue and the Schmallenberg virus a worldwide economic boom. So in 2001 6.9 billion dollars have been implemented worldwide. 2009, there were approximately $ 25 billion and in 2015, worldwide sales are estimated in vaccine production to 56-64 billion dollars.