Vaccination and Immunity

A vaccine is a biological preparation that provides active acquired immunity to a particular disease. A vaccine typically contains a suspension of disease-causing microorganism and is often made from weakened (attenuated) or killed forms of the microbe, its toxins, or one of its surface proteins.  The agent stimulates the body's immune system and produces antibodies.

• Plague is an infectious disease caused by the bacterium Yersinia pestis.
•  Killed bacteria have been used since 1890 but are less effective against pneumonic plague so that recently live vaccines of an attenuated type and recombination protein vaccines have been developed to prevent the disease.
• Synthetic capsular polysaccharide vaccines are used for the treatment of pneumonia and meningitis. 
• Hence, Synthetic capsular polysaccharide material cannot be used for the preparation of vaccination against the plague. 
• So, the correct answer is 'Synthetic capsular polysaccharide material'.

Smallpox is a serious viral disorder caused by the variola virus. Variola virus is an orthopoxvirus, an enveloped DNA virus. The infection starts by exposure of the virus in the nasopharynx and characterized by fever and malaise. 

• Conjugate vaccines combine a weak antigen with a strong antigen so that the immune system has a stronger response to the weak antigen. Example: Haemophilus influenza.
•  Toxoid vaccine is made from a toxin (poison) that has been made harmless but that helps in an immune response against the toxin. They are based on the toxin produced by certain bacteria (e.g. tetanus or diphtheria). An
• The attenuated vaccine is a vaccine created by reducing the virulence of a pathogen, but still keeping it viable. Example are Measles, mumps, rubella, yellow fever. 
• Inactivated whole-cell vaccines are made from microorganisms (viruses, bacteria, other) that have been killed through physical or chemical processes. An example is Polio, bubonic plague, Hepatitis A.

Tetanus vaccine, also known as tetanus toxoid (TT), is an inactive vaccine used to prevent tetanus. A person likely to develop tetanus is immunised by giving pre-formed antibodies and it produces passive immunity. In passive immunity, the antibodies are produced in some other animals in response to given antigen. These pre-formed antibodies are then injected into the humans at the time of need or emergency.

• Tuberculosis is an infectious disease usually caused by Mycobacterium tuberculosis bacteria. Tuberculosis generally affects the lungs, but can also affect other parts of the body. The symptoms of active TB is a chronic cough with blood-containing sputum, fever, night sweats, and weight loss.

• Bacillus Calmette–Guérin (BCG) vaccine is a vaccine primarily used against tuberculosis (TB). In most tuberculosis (TB) endemic countries, bacillus Calmette Guérin (BCG) is usually given around birth to prevent severe TB in infants.

• Hence BCG vaccine provides protection against TB.

• So, the correct answer is 'T B'.

DPT vaccine is a combination vaccine containing Diphtheria toxoid, Tetanus toxoid, and heat-killed Bordetella pertussis cells.

The smallpox vaccine protects people from smallpox by helping their bodies develop immunity to smallpox. The vaccine is made from a virus called vaccinia, which is a poxvirus similar to smallpox, but less harmful. The smallpox vaccine contains live vaccinia virus, not a killed or weakened virus like many other vaccines. For that reason, people who are vaccinated must take precautions when caring for the place on their arm where they were vaccinated, so they can prevent the vaccinia virus from spreading. The vaccine does not contain the smallpox virus and cannot give you smallpox. For most people with healthy immune systems, live virus vaccines are effective and safe. Smallpox vaccination can protect you from smallpox for about 3 to 5 years. After that time, its ability to protect you decreases. If you need long-term protection, you may need to get a booster vaccination. 

So, the correct option is 'Weakened germs'.

DPT (also DTP and DTwP) refers to a class of combination vaccines against three infectious diseases in humans diphtheria, pertussis (whooping cough), and tetanus. The vaccine components include diphtheria and tetanus toxoids and killed whole cells of the organism that causes pertussis (wP).

Explanation: The oral polio vaccine contains a live attenuated virus, that is, the live virus that is capable of multiplying but generally incapable of causing infection. The injectable polio vaccine contains the killed virus.

The complexity of the malaria parasite makes the development of a malaria vaccine a very difficult task. Vaccines are based on triggering an immune response in humans that is known to protect against an infection but there is no such response to malaria in humans.

Measles-mumps-rubella vaccine (MMR live attenuated vaccine) is not advisable during pregnancy because there is a risk to the foetus.

Explanation: Because chickenpox is airborne and is so contagious before the rash appears, it is difficult to avoid. A chickenpox vaccine is available. It is about 100 per cent effective against moderate or severe illness, and 85 or 90 per cent effective against mild chickenpox.

First generation vaccines carry the live, 'damaged' or dead entire organism. They impart immunity by inducing the antibody immune response and the immune resposes entailing killer and helper T-cells. Since the attenuated vaccines can still turn into the toxic form and could cause disease; the second generation vaccines were developed which are made up of protein antigens or recombinant proteins and function by inducing antibody responses, but not killer T cell responses. The third generation vaccines are the DNA vaccines which have a round small modified bacterial DNA and release one or more particular antigens. The Hepatitis B and Herpes virus vaccines carry hepatitis B surface antigen and thus are the second generation vaccines.