Vaccines

Vaccines.

  • Posted: 1/25/2017
  • By: Alvizia Healthcare

What are Vaccines?

Vaccine is a product (biological preparation) that gives (provides) active immunity to an individual against a particular disease. It can be administered through an injection or given orally. It basically contains an agent which resembles the disease causing pathogen that induces the activation of antibodies by our immune system. Our immune system recognizes it as a threat; destroys it and also remembers it.

What is immunity?

Whenever your body encounters a foreign organism, like bacteria or a virus, a complicated set of responses are set in motion. Your body has two sets of defensive mechanisms, one called 'innate immunity' and another called 'adaptive immunity'.

Innate immunity is an in built property that is present from the time of birth. Adaptive or acquired immunity is usually developed by vaccines. There are also many injections available that boosts the natural immunity of our body like ATMOFERON .

Effectiveness of vaccines

Vaccines have been very effective in fighting and eradication of infectious diseases. Although there are certain limitations, but most childhood vaccines provide immunity 90-100% of the time. Vaccines have been responsible for the eradication of small pox. Other diseases like polio, measles and typhoid have seen a drop in the recent years.

Safety

Vaccines are safe medical products available. All vaccines are approved by FDA (Food and drug administration). A vaccine must go through extensive tests like clinical trials before being approved. After administration of vaccine, minor and temporary side effects like mild fever, headache is reported are seen. This is seen noted as the body's immune system is reacting to the foreign agent, the reaction resulting in a mild fever.

Types of vaccines
  • Live attenuated - These vaccines have contains a living microorganism which has been weakened so that it cannot cause disease. These are usually viral vaccines but some bacterial vaccines are also seen.
    Example – BCG, plague
  • Inactivated – these vaccines contain microorganism that has been killed by heat treatment, radiation or chemicals. These vaccines have been produced by killing the disease-causing microbe with chemicals, heat, or radiation.
    Example - polio, influenza, cholera
  • Toxoid – it contains inactivated toxic compounds secreted by microorganism that causes the disease rather than the organism itself.
    Example – tetanus, diphtheria
  • Subunit – it consists of protein subunit that acts as an antigen. Rather than the entire organism, a part of it is used as vaccine.
    Example – Hepatitis B
  • Conjugate – bacteria contains an outer polysaccharide coat. This coat is linked with a protein is used as a vaccine thereby making the immune system to recognize the bacteria based on its outer coat.
    Example–Haemophilus influenzae type B vaccine
Other types are present like DNA vaccines and recombinant vector vaccine which is in experimental stages.

DNA vaccines involve administering the viral DNA or bacterial DNA directly into the cell by different methods like needle injection or bombardment of gold particle.

Recombinant vector vaccine uses the recombinant vector to induce immunity. Vector is basically a carrier. Here it can be an attenuated bacterium or virus.

Delivery methods

Vaccines are usually delivered through needle and syringe. Oral vaccines have come up. Polio is presently the only oral vaccine. Microneedles are still in developmental stage. Edible vaccines are also coming up where transgenic plants are being used. Plants like potato and banana are used to produce vaccines that are usable for humans.

Indian companies that produce vaccines

Many pharmaceutical companies like Panacea Biotech (New Delhi), Haffkine Biopharmaceuticals (Mumbai), Bharat Biotech (Hyderabad) and Indian Immunologicals (Hyderabad) is present that produce vaccines.