Vaccines The word " vaccine - PowerPoint Presentation

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Vaccines

The word "

vaccine" was created by Edward Jenner which comes from the Latin word vacca, meaning cow. A virus that mainly affects cows (cowpox). Smallpox vaccine, the first successful vaccine to be developed, was introduced by Edward Jenner in 1796. He followed up his observation that milkmaids who had previously caught cowpox did not later catch smallpox by showing that inoculated cowpox protected against inoculated smallpox. Edward Jenner is known as Father of vaccine. In 1798, the 1st smal pox vaccine was developed after he inoculated a 13 year boy with vaccinia virus. Inoculated vaccinia protected against inoculated variola virus. A vaccine works by training the immune system to recognize and combat pathogens, either viruses or bacteria. By injecting these antigens into the body, the immune system can safely learn to recognize them as hostile invaders, produce antibodies, and remember them for the future.Vaccination is the administration of a vaccine to stimulate an individual’s immune system as an effective method of combating infectious diseases and to develop protection from a disease.Vaccines are used to boost the immune system and prevent serious, life-threatening diseaseshelp to defend when germs, such as viruses or bacteria, invade it.Vaccines expose us to a very small, very safe amount of viruses or bacteria that have been weakened or killed.Immune system of our body learns to recognize and attack the infection when exposed to it later in life to deal with infectious diseases. All vaccines contain an active component (the antigen) which generates the protective immune response. Vaccines may also contain additional components.

WHY WE NEED VACCINES

For a few weeks after birth, babies have some protection from germs that cause diseases. This protection is passed from their mother through the placenta before birth. After a short period, this natural protection goes away and the necessity of vaccine arise.

Due to increased international travel, migration and ecological changes, the ability of emerging infectious diseases to spread and cause devastation is increasing. Vaccines can be a key tool in managing this threat – but only if we have them ready for diseases when they appear.Help to limit drug resistance. Medicine relies on being able to treat infectious diseases with antimicrobial drugs, such as antibiotics, but overuse and misuse of these drugs is lethal.Protect us from dangerous diseases. In some regions or populations, dangerous diseases are constantly present (endemic). Examples include hepatitis B, cholera and polio. So long as these diseases are around, we need vaccines to booster our immune systems and protect us from harm.Protect children and the elderly. Our immune systems are strongest in adulthood, meaning that young children and the elderly are particularly susceptible to dangerous infections. By strengthening our immune systems early and late on in life, vaccines bypass this risk. Protect the vulnerable. If enough of a population is vaccinated, infections can’t spread from person to person, which means that everyone has a high level of protection – even those who don’t have immunity. This is known as herd protection (or herd immunity). It’s important because not everyone can be directly protected with vaccines – some people are unresponsive to them or have allergies or health conditions that prevent them from taking vaccine. Help to control epidemics. In a world of increasing infectious diseases, the pathogens becoming drug resistant. Vaccines reduce the opportunity for drug resistance to develop. Most effective health intervention. Vaccines prevent an estimated 2–3 million deaths worldwide every year. But, a further 1.5 million lives could be saved annually with better global vaccine coverage.  vaccination

Types of vaccines

Live virus vaccines

use the weakened (attenuated) form of the virus. The measles, mumps, and rubella (MMR) vaccine and the varicella (chickenpox) vaccine are examples.Killed (inactivated) vaccines are made from a protein or other small pieces taken from a virus or bacteria. The whooping cough (pertussis) vaccine is an example.Toxoid vaccines contain an inactivated toxin or chemical from the bacteria or virus. Examples are the diphtheria and tetanus vaccines.Biosynthetic vaccines contain manmade substances that are very similar to pieces of the virus or bacteria. The Hepatitis B vaccine is an example. Subunit, recombinant, polysaccharide and conjugant vaccines are biosynthetic vaccines.

Biosynthetic Vaccines

Subunit Vaccine

: A subunit vaccine is a fragment of a pathogen, typically a surface protein, that is used to trigger an immune response and stimulate acquired immunity against the pathogen from which it is derived. Contains the minimal microbial elements necessary to stimulate long lasting protective therapeutic immune response. Diphtheria, tetanus, pertussis, hepatitis B, human papillomavirus, Haemophilus influenzae type b, meningococcal, and pneumococcal vaccines are subunit vaccines. Subunit vaccine is being used for plague immunization. Conjugate vaccines: Conjugate vaccines combine a weak antigen as with a strong antigen as a carrier so that the immune system has a stronger response to the weak antigen. The most commonly used conjugate vaccine is the Hib conjugate vaccine. Pathogens that are combined in a conjugate vaccine to increase an immune response are Streptococcus pneumoniae and Neisseria meningitidis, both of which are conjugated to protein carriers like those used in the Hib (Haemophilus influenzae type b)conjugate vaccine, meningococcal vaccine and pneumococcal vaccine.Polysaccharide vaccines: A unique type of inactivated subunit vaccine composed of

long chains of sugar molecules

that make up the

surface capsule of certain bacteria

. Only the

sugar part of the bacteria

,

the capsule

, is included as

the antigen

to

stimulate the immune response.

Meningococcal and Pneumococcal vaccines are this type of

Polysaccharide vaccines.

Recombinant vaccines

:

The

gene segment of a protein

from the

disease-causing organism

that is known to

stimulate a protective immune response

(

protein of interest

) is inserted into the gene of another cell, such as a

yeast cell

. When the cell replicates it has the same shape as the protein of interest. Yeasts cells are used for the hepatitis B and human Papillomavirus Schedule vaccines

Infanrix-hexa

(prevent

diptheria

, tetanus

, pertussis

,

hepatitisB

, poliomyelitis and

Haemophilus

influenzae

type b(

Hib

).

Immunization

According to WHO, Immunization

is the process whereby a person is made immune or resistant to an infectious disease, typically by the administration of a vaccine. Vaccines stimulate the body's own immune system to protect the person against subsequent infection or disease.The artificial process by which specific antigen or attenuated pathogens are introduced in the body of a normal person for production of large quantity of antibodies. Vaccination is done either by introducing antigens or killed organisms or by toxoid or by live vaccines in the form of attenuated organisms.Vaccination is the term used for getting a vaccine – that is, actually getting the injection or taking an oral vaccine dose. Immunisation refers to the process of both getting the vaccine and becoming immune to the disease following vaccination.Usually, if mutation happens to microbe, it might render the vaccine ineffective (this is the reason why common cold has no vaccine)Differences Between Vaccination And ImmunizationVaccinationImmunizationThe process involves Introducing a weakened / deactivated disease causing microbes into a personThe process starts after the person is exposed to the vaccine and the body starts building resistance to that diseaseIt is usually injected or administered orallyIt is not administered in any way, the body develops the resistance from vaccinesImovax Rabies is the trade name for rabies vaccineThe body builds up immunity through this vaccine for the disease rabiesVaccination does not guarantee complete resistance to a diseaseComplete immunity occurs when the person fully recovers from the disease

Immunization and vaccination

Different Protocols to Immunization

Immunization

can be achieved in an active or passive manner: vaccination is an active form of immunization.Active Immunization: Active immunization occurs when the immune system stimulates the body to produce antibody and other immune responses (e.g., cell-mediated immunity) against any antigen or pathogen enters the body. It stimulates the immune system to produce antibodies against a particular infectious agent. If the person encounters that pathogen again, long-lasting immune cells specific to it will already be primed to fight it because of immunological memory i.e. retain the memory of prior antigenic exposure which is more effective. Natural Active Immunization occur when someone is exposed to a pathogen. For example, an individual who recovers from a first case of the measles is immune to further infection because the antibodies against the pathogen are already present. Artificial active immunization is where the immune system is activated by a known antigen (the immunizing agent) . The immunizing agent is the antigen which is the inactive version of pathogen (i.e. a vaccine or a toxoid), are injected into the person. The vaccine will cause an immune response, but it won't actually cause the disease.

Passive immunization

:

Passive immunization

is the term used when

antibody formed in one individual is given to another individual

who

is at risk of infection

— the protection is temporary

. Antibody is not forming within the body of

the infected individual.

An important

example is the

administration of rabies

immunoglobulins

[

HRIG or ERIG

] derived

from human and equine sources

.Natural Passive immunization occurs physiologically, when antibodies are transferred from mother to foetus during pregnancy, to protect the fetus before and shortly after birth. A substance called colostrum, which an infant receives during nursing sessions in the first days after birth and before the mother begins producing “true” breast milk, is rich in antibodies and provides protection for the infant. Breast milk, though not as rich in protective components as colostrum, also contains antibodies (IgA) that pass to the baby. This protection provided by the mother, however, is short-lived. During the first few months of life, maternal antibody levels in the infant fall, and protection fades by about six months of age.Artificial passive immunization is normally administered by injection and is used if there has been a recent outbreak of a particular disease or as an emergency treatment for toxicity, as in for tetanus. The antibodies can be produced in animals, called "serum therapy," although there is a high chance of anaphylactic because of immunity against animal serum itself. Humanized antibodies produced in vitro by cell culture are used instead if available.

Active Immunity vs Passive Immunity

Active Immunity

Passive ImmunityActive immunity is a permanent immunity produced by the antibodies of the host in response to a direct contact of an antigenPassive immunity is a short-term immunity produced by the introduction of antibodies from outside to the hostImmunity doesn’t occur immediately. A time lag occurs for its developmentImmunity develops immediately. There is no time lagIt generates an immunological memoryDoesn’t generate immunological memoryWhen the antigens enter the body naturally, antibodies and specialized lymphocytes are induced by the body.Antibodies are passed from a mother to a fetus through the placenta and to an infant via mother’s milk.No side-effectsIt may cause reactions

Immunological

memory

Immunological memory is the ability of the immune system to quickly and specifically recognize an antigen that the body has previously encountered and initiate a corresponding immune response. Generally these are secondary, tertiary and other subsequent immune responses to the same antigen.Immunological memory is responsible for the adaptive component of the immune system, special T and B cells, the so called memory T and B cells, The immunological memory is the basis of vaccination.

Immunity

Vaccines can be made from various sources. Some of the Viral and Bacterial Vaccines and their composition are given below.

Kind of Diseases

ViralHepatitis B Subunit vaccineInfluenza Attenuated VirusMeasles (Rubeola virus) virus Attenuated virus Polio Attenuated and dead virus Rabies (Rabis lyssa virus) Attenuated and dead VirusRubella Attenuated VirusSmall Pox (Variola major and variola minor Attenuated VirusYellow Fever (Flavivirus) Attenuated VirusBacterial Body parts of Vibrio Cholera cholerae Tuberculosis Attenuated Microbacterium tuberculosis Plague Dead Yersinia pastisHaemophilius meningitis Dead Haemophilius

influenzae

Whooping cough Dead

Bordetella

pertussis

Pneumonia Dead

Streptococcus

pneumoniae

Rickett

Dead

Rickettsia

rickettsii

Composition of Vaccine

Vaccination as per the National Immunization schedule by Government of India

Age

National Rural Heath Mission BirthBCG (Bacillus Calmette- Guerin),OPV(0),Hep B Birth dose(To be given at the place of delivery) 6 WeeksOPV1, Penta1(DPT+HepB+HiB) 10 WeeksOPV2, Penta2(DPT+HepB+HiB) 14 WeeksOPV3, Penta3(DPT+HepB+HiB),IPV 9 MonthsMMR-1, /MR/Measels,JE Vaccine-1 16-24 MonthsMMR-1,OPV Booster,(Oral Polio Vaccine)DPT 1st Booster,JE Vaccine-2  5-6 YearsDPT 2nd Booster 10 YearsTT1 (Tetanus toxoid) 16 YearsTT2