Vakcine i serumi

Maturski, seminarski i diplomski radovi iz medicine.

Vaccines are a simple and efficient method of protection against contagious diseases for which they have been developed. Vaccines have eliminated several quite dangerous and lethal diseases, which are nowadays just a matter of theory, with no clinical examples, as they have been eradicated. However, since the microorganisms which cause those diseases still live in our environment, we are obliged to maintain a high level of protection in our community. This prevents those almost forgotten diseases to appear again. Upbringing and maintenance of communal immunity is achieved by the inoculation of every single man, woman and child, so it should not be perceived only as preservation of our own health, but also as a contribution to the health profile of the whole community.

Young children are in the greatest danger, and that is the reason why they should be inoculated as early as possible, even in the first days of their lives. Since mother gives not only food to the fetus, but also the antibodies she developed during her life, by inoculation or natural immunization, a child is usually protected for the first 6 month of its life. The child should develop its own antibodies as soon as possible, in order to enable longer protection. The 6 month period during which the child is protected by mother’s antibodies is used for inoculation and stimulation of child's own defense system. The vaccines given in one or two doses provide much better and longer-lasting protection for the child. At the age of one or no later than 15 months after birth, a child should complete its inoculation and get all the necessary vaccines. Breast-feeding presents one way of inoculation and it is called „passive protection”, since colostrum, the thick yellow milk that mothers have in the first few days contains antibodies for all the diseases the mother had in her life. This is also one of the reasons why mother’s milk is the best food for the baby, at least in the first 12 months. This way passive protection of the child can be prolonged for several months.

It has been well-known for centuries that when a person recovers from one disease, they can not succumb to it again. The idea to inject small amounts of smallpox fluid under the skin of healthy people (variolation) was an unsuccessful attempt to copy that natural phenomenon. In 1796, Jenner introduced inoculation with fluid from cow pox retrieved directly from cows as a prophylaxis against smallpox, and that was the first documented use of an attenuated vaccine which marked the beginning of the modern inoculation.

Vaccine production

Vaccine is a biological preparation which improves immunity to a particular disease. It is made of weakened or killed forms of the microbe or its toxins which are used to stimulate the immune system and create antibodies. Viruses and bacteria are previously killed or weakened in labs, so that our cells would be able to defeat them easily and create antibodies for any future attack of the same enemy. A vaccine creates immunity for a specific decease, and is the most effective and efficient prevention against diseases and lethal contagious diseases.

Diseases which can be prevented by vaccines

Tuberculosis, (difficult forms of TBE such as consumptive meningitis), diphtheria, tetanus, whooping cough, Polio (Poliomyelitis), meningitis caused by Haemophilus influenza type B, measles, mumps, rubella and infectious hepatitis caused by hepatitis B.

World Health Organization and health providers all over the world use following abbreviations and phrases for vaccines in mutual communication, administration and evidence:

BCG vaccine against T.B.E
T.D.P vaccine against diphtheria, tetanus and whooping cough
D.T vaccine against diphtheria and tetanus
Td vaccine against diphtheria and tetanus for older children and adults
TT vaccine against tetanus
OPV vaccine against Polio (attenuated)
IPV vaccine against Polio (inactivated)
MMR vaccine against measles, mumps and rubella
HepB vaccine against hepatitis B
HiB vaccine against hemophiliac influence type B

Full inoculation consists of two parts – vaccination and re-vaccination (for refreshing, firming and prolonging the effects of inoculation)

Vaccine can be applied in several different ways:
1.Orally – by swallowing
2.By injection – intramuscular, intradermal
3.By puncture – shallow under the skin
4.Nasally – through the nose

Types of inoculation

Inoculation causes creation of antibodies for an infective agens or its toxic products. It can also stimulate a cellular reaction of lymphocytes and macrophages. The most important antibodies are those which inactivate toxic protein bacterial products (antitoxins), facilitate facilitosis – intracellular digestion of bacteria (opsonynes), react with the serum complement components and damage bacterial membranes, leading to bacteryolisis (lysine) or prevent the proliferation of infectious virus (neutralizing antibodies).

In the last couple of years, antibodies reacting with components of bacterial surface have been much more appreciated, since they prevent bacteria from attacking the mycoses surfaces (antiathesines). Some antibodies do not have to be protective, because they can “block” the response of the protective antibodies and decrease the defense system in the organism.

Antigens react with antibodies inside the bloodstream, fluids and on mycoses surfaces. If the infection is inside the cells, for example a viral replication, antibodies have a problem reaching it. On the other hand, antibodies are efficient against so many viral infections since they react with the virus before it penetrates inside the cell, and can prevent a locally multiplied virus from spreading from the penetration point towards the organ it attacks. An example of this would be polio, which spreads from the digestive system towards central nervous system or XXX which spreads from entrance wound towards peripheral nervous tissue.

Lymphocites react on their own, and antibodies corelate with lymphocitic K-cells, in order to recognize superficial changes on cells infected with a virus, and destroy them.

Passive inoculation

This type of inoculation is therapeutic, as antibodies are used for theapy and not prophylacse. This type of vaccine marks the intruder and neutralises it. If we suspect the infection has already began, for example with tetanus, a person can have both, an active and a passive vaccine, prophylactic and therapeutic. Mother's milk contains antibodies from her own immune system, acquired both naturally and by inoculation. Breastfeeding presents an amazing protection against many diseases, and mother milk is an exellent source of passive vaccines. However, passive vaccines provide protection only for a short period of time. The baby starts producing antibodies, so as soon as the source is unawailable, passive immunity no longer exists. Antibodies in the form of serums of imunoglobulines, from no less than two different donors inoculated or recovered from disease, can provide temporary protection for a person who has none. This is why passive inoculation is useful for those who cannot produce their own antibodies, or those who can be infected, but have no time for an active vaccine, since it takes between 7 and 10 days to stimulate the imune system and create a proper immunity. Antibodies can be of human or animal origin, and the animal ones could be dangerous. Sometimes humans can have an immunoreaction on animal proteins, resulting in the quick removal of protective molecules from the recipient's system and the serum disease. In order for human and animal vaccine to achieve the same effect, larger quantities of vaccine are necessary. In addition, no animal origin vaccine can be used without a thorough check for any possible alergic reactions to the animal species the vaccine originated from. Patients alergic to other antigenes are more likely to have a serum reaction. Whenever we use the non-human serum, we must have a syringe with water solution on our hands, (1:1000 ratio). If the allergy is in the medical history or it has been proven by testing the patient, the patient can be treated by applying small fractions of doses, so as to increase tolerance with progressively higher dosages. During the procedure, it can be necessary to treat the patient with steroids or antihistamines in order to limit the alergic reaction.

Before antibitics, passive imunisation was used with limited succes as a treatment for neumococal or streptococal infections.

Before the discovery and use of the antibiotics, passive imunisation was used with a limited success as a treatment for infections caused by pneumococcus or haemophilus. In order to get the antiserum which would be appropriate for a specific type, it was necessary to identify the infectious serotype. Eventually, this insertion of non-native proteins resulted in a disease and the therapy success rate was relatively low. However, because of the accessibility of the human hyperimmunoglobulin encouraged by the vaccine and the infections by microbes immune to antibiotics, which result in a constantly high level of mortality, the treatment with the serum is again being taken into consideration. Thus far, the serum treatment for the diseases that are still being studied is usually limited to antivenin, botulinum, tetanus and diphterial antitoxins whose task is to block still unlinked toxins. The application of immunoglobin has no significance in the prevention of regressive infection if ?????????????

The dangers of passive inoculation

A disease may develop after one injection of an unknown serum, but it is much more common with the patients to whom the proteins of the same or similar kind have already been initiated. According to the gravity, the reaction ranges from an acute anaphylaxis (with urticaria, back pain, asthma, cardiovascular collapse, even death) to the serum disease which may occur a few hours or days after the treatment. Typical symptoms of serum disease are adenopathy, urticaria, arthritis, and fever. Demyelinating encephalopathy has also been described. Giving human serum has rarely been followed by similar allergic reactions. The medical staff must be trained in giving a standard serum, so as to avoid accidental intravenous application. Nowadays most human and animal serums are given intramuscularly. All of them contain great mollecul masses, which, if applied intravenously, cause medium or heavy anaphylactic reaction with a possible vasomotor collapse and death. Standard serum cannot be mixed with the intravenous immunoglobulin, which has been released to the market only recently and which can safely be given inrtavenously. Application of undamaged lymphocytes in order to increase cellur immunity is also dangerous if the recipient's immune system is too suppressed and is not capable of stopping the implantation of donor's cells. Donor's transplanted cells could then reject the recipient, and possible outcomes are rash, pancitopenia, fever, diarrhoea, hepatosplenomegaly and death.

Attenuated vaccines

With active immunisation a microorganism is infected with another misroorganism which has been prevented from multiplying by human intervention. The immune system does not know that, so it takes all precautions in order to identify, mark and destroy this "infertile" intruder. The patient may feel mild symptoms of the immunological reaction (headache, fever), but since the germ would not multiply, there would be no other symptoms. To sum up, active immunisation is a simulation of an infection and has a preventing role.

Active immunisation can be done with a live or dead material. Dead antigens are usually the structural components of an infective microorganism which encourage the creation of antibodies that prevent the infection, or an detoxificated bacterial product (toxoid) which induce antitoxins and they prevent the illness by indirect inhibition of pathogens. While tetanus toxoid creates a long-lasting immunity of at least ten years, many dead vaccines enable protection only for a limited amount of time. In order to achieve a mid-level of protection against the plague, influenza, cholera and typhoid fever, the antigen has to be