Vaccine, Vaccination and Immunization
A vaccine is a biological formation that gives active acquired immunity against a specific disease.
A vaccine is ‘biological’ because it is made up of completely killed or weakened (attenuated) form of microorganism, its toxin or protein part is use for vaccine.
Vaccination (administration of vaccine)
Is the process in which a injection of killed or weakened form of microorganism is administered to any organism.
Vaccination triggers the immune system which activates B and T cells of body against that specific microbe.A vaccination can be given orally or intravenously to individual depend on its effectiveness.
Is the process by which a person or animal becomes protected from emerging disease for that specific microbe
During immunization host immune system become activated for injected microbes and defense against that during this period host cells also produce memory cells so that if in future same microbe attack then it can recognize and destroy easily.so its very important after a vaccination host immune should be activated to make antibodies against vaccinated pathogen to give protection from later exposure of same pathogen.
Brief History of vaccine
Term vaccine and vaccination derived from Variolae vaccinae (small pox of cow) and term vaccine given by Edward Jenner (in 1798) called as father of vaccine.
Classification of vaccine
- Live attenuated or weakened vaccine
- Killed or inactivated vaccine
- Toxoid vaccine
- Conjugate vaccine
- Subunit vaccine
- DNA vaccine
- Recombinant vector vaccine
Live Attenuated vaccine
Vaccine is produced by modifying a pathogenic (wild) virus or bacterium in a laboratory by reducing their pathogenicity. The resulting organism retains the ability to replicate and trigger host immune system, but usually does not cause illness.
Live attenuated vaccine list
- Measles Mumps Rubela (MMR combined vaccine)
- Vaccinia (Smallpox)
- Polio vaccine(sabin)
- Influenza(nasal spray)
- BCG vaccine
Mechanism of live vaccine after vaccination
A small dose of vaccine is enough to trigger immune system of host. Live attenuated microbe must be replicate inside the host after vaccination. Although live attenuated microbe replicate in the host but do not cause any illness such as may occur with wild form. The immune response produce is similar to natural infection by wild organism. Active immune cells kill the microbe and produce memory cell against microbe for later exposure of same pathogen.they elicit T cell response with antibodies.
Advantage of live vaccine
- They multiply like natural organism inside the host.
- Require fewer doses and boosters of vaccine.
- Their effectivity is long lasting.
Disadvantage of live vaccine
- Not Safe for immunodeficient and pregnant individual.
- require special storage treatment
- Live attenuated microbe can be revert to its wild form by back mutation.
- They can produce severe or fatal effects.
Killed vaccine or inactivated vaccine
Inactivated vaccine are produced by growing the bacteria or virus in culture media,then inactivating it with heat or chemical usually formalin.inactivated vaccine are not live and cannot replicate. These dose cannot cause disease from infection and can also safe for immunodeficient people. They always require multiple doses to trigger immune response.they only activate B cell immune system.
Inactivated vaccine list
- polio vaccine (salk)
- influenza vaccine
- typhoid vaccine
- cholera vaccine
- plague vaccine
- pertussis vaccine
Advantage of killed vaccine
- Safe to use and can be given to immunodefficient and pregnant individual
- Cheaper than live attenuated vaccine
- Storage is not critical as attenuated vaccine
Disadvantage of killed vaccine
- Microorganism cannot multiply so periodic boosters must be given to maintain immunity.
- Only humoral immunity can be induced
- Most killed vaccine has to be injected
Is a bacterial toxin usually exotoxin. These vaccine are used when bacterial toxin is main cause of illness. These vaccine are made up of inactivated or suppressed toxin of bacteria by chemical or heat treatment. Toxoid vaccine are use for the treatment of tetanus,diphtheria,botulism.
Advantage of toxoid vaccine
- Highly immunogenic
Disadvantage of toxoid vaccine
- need of adjuvant
- possible contamination by toxin
- may occasionally cause allergic reaction.
Some bacteria have outer layer of polysaccharide which give them protection as host immune system is not able to recognize potently, so conjugate vaccine is created by covalently attaching a poor antigen to strong antigen thereby eliciting a stronger immune response to poor antigen. These vaccine are given to those individual who are young or infants.
Example : Haemophilus influenzae type B (Hib),pneumococcal vaccine in children
Advantage of conjugate vaccine
- more immunogenic
- effective in young children also
- T cell involvement
- Long term protection.
Instead of entire microbe subunit vaccine are only a antigen part of microbe that stimulate the immune system. In some cases only epitope part is use which is specific for antibodies of B cells to make the reaction.
Example: subunit vaccine made for Hepatitis B virus.
Advantage of subunit vaccine
- No risk of pathogenicity
- Various rout of administration
- Simplified large scale production
- Further engineering possible
- Long term persistence of immunogen
- Cost effectiveness
Disadvantage of subunit vaccine
- Multiple doses require to stimulate immune response
- Adjuvant needed
Once the gene form a microbe has been analyzed, DNA vaccine made against it. DNA vaccination is a technique for protecting against disease by injecting genetically engineered DNA so cells directly produce an antigen, producing a immune response.DNA vaccine are made up of a plasmid.
Advantage of DNA vaccine
- Induction to long term immune response
- Involve both humoral and cellular immune response
- Heat stable
- Ease of large scale production
Disadvantage of DNA vaccine
- Integration of host vaccine DNA in to host genome
- Formation of anti nucleic acid antibodies possible
- Concept restricted to peptide and protein antigen.
Recombinant vector vaccine
Similar to DNA vaccine,but they use attenuated or killed virus or bacterium to introduce microbial DNA to cells of host. Vector refer to virus or bacteria used as carrier. Example : vaccinia vector vaccine.
Advantage of Recombinant vector vaccine
- Easy to make
- Long lasting protection
- Stimulate both humoral and cell mediated immunity
Disadvantage of Recombinant vector vaccine
- Continuous antigenic stimulus may led to tolerance or autoimmunity
Some important reasons to vaccinate everyone
Immunization can save your child’s life: Because of advances in medical sciences, your child can be protected against more diseases than even before. Some diseases that once injured or killed thousands of children, have been eliminated completely and others are close to extinction– primarily due to safe and effective vaccines. polio is one of example.
Vaccination is very safe and effective: Vaccines are only given to children after a long and careful review by scientists, doctors, and healthcare professionals. Vaccines will involve some discomfort and may cause pain, redness, or tenderness at the site of injection but this is minimal compared to the pain, discomfort. Serious side effects after vaccination, like severe allergic reaction, are very rare. The disease-prevention benefits of getting vaccines are much greater than the possible side effects for almost all children.
Immunization can save your family time and money: vaccination at a proper time for children prevents the risk of disease. Some vaccine-preventable diseases can result in prolonged disabilities and can take a financial toll because of lost time at work, medical bills or long-term disability care. In contrast, getting vaccinated against these diseases is a good investment and usually covered by insurance.
Immunization saves future generation: Vaccines reduced and, in some cases, eliminated many diseases that killed or severely disabled individuals just a few generations ago. For example, smallpox vaccination eradicated smallpox disease completely. Your children don’t have to get smallpox shots anymore because the disease no longer exists. By vaccinating children against rubella, the risk that pregnant women will pass this virus on to their fetus has been decreased. If we continue vaccinating now, and vaccinating completely, parents in the future may be able to trust that some diseases of today will no longer be around to harm their children in coming future.
Vaccination will keep you healthy: The Centers for Disease Control and Prevention (CDC) recommends vaccinations from birth through adulthood to provide a lifetime protection against many diseases, such as influenza, pneumococcal disease, human papillomavirus, and hepatitis A and B. So its important to be vaccinated to become healthy.
Your family and coworker needs you: Each year we know many of people get sick from vaccine preventable disease. Due to this they suffered a lot as not healthy they need care of others and not able to do their work so its really important aspect of life to get healthy for yourself first.
Why Vaccination for child is mandatory
Children need vaccine in their starting age as their immune system is weak against all diseases, and at that time if any infection occur it become more difficult to cure.
so vaccination is the best way to protect your child from dangerous diseases. Your child should receive all the recommended vaccine
schedule for vaccination for mother and her child
A disease caused by clostridium diphtheriae in child can led to difficulty in breathing, heart failure, paralysis and even death. vaccination used for this is dTap provide protection against diphtheria, tetanus and whooping cough.
A disease caused by varicella zoster virus,it infect all age group mainly child and immunodeficient people and have a lot of blisters in all over the body with severe pain and fever. This is a life threatening disease. vaccine used for this is varicella vaccine.
3. Pneumococcal Disease
A disease caused by Streptococcus pneumoniae. it causes ear infection, sinus infection ,pneumonia and meningitis. vaccine used for this is pneumococcal conjugate vaccine.
A disease caused by poliomyelitis virus.It is a crippling and potentially deadly infection.virus cause paralytic infection.vaccine used for polio is salk and sabin vaccine.
A disesae caused by clostridium tetani.Tetanus causes painful muscle stiffness and lockjaw and can be fatal. Parents used to warn kids about tetanus every time we scratched, scraped, poked, or sliced ourselves on something metal. Nowadays, the tetanus vaccine is part of a disease-fighting vaccine called DTaP, which provides protection against tetanus, diphtheria, and pertussis (whooping cough).
A disease caused by Rubella virus.It is especially dangerous for a pregnant woman and her developing baby. If an unvaccinated pregnant woman gets infected with rubella, she can have a miscarriage or her baby could die just after birth.
7. Haemophilus influenzae
Hib (or its official name, Haemophilus influenzae (type b) isn’t as well-known as some of the other diseases Hib mostly affects kids under five years old. Before the vaccine, over 20,000 kids were infected each year.
A disease of skin caused by measles virus of genus morvillivirus. cause skin and respiratory infection.it is a contagious disease. MMR vaccine is used to prevent it.