Vaccination and Immunity

Active acquired immunity occurs when the body produces its own antibodies in response to an exposure to an antigen, such as an infection or vaccination. Passive immunity involves receiving antibodies from an external source.

• Vaccines which are to be avoided during pregnancy include rubella vaccine, small pox vaccine and oral polio-myelitis vaccine

A vaccine is a biological preparation that provides acquired immunity to a particular disease. A vaccine typically contains an agent that resembles a disease-causing micro-organism and is often made from weakened (attenuated) or killed forms of the pathogen, its toxins or one of its surface proteins.
Therefore, the correct answer is option C.

These are the antigenic substance produced from the causative agent of disease, which helps in providing immunity against one or more disease. BCG stands for Bacille Calmette Guerin, is the vaccine provided against the disease tuberculosis (TB). It is given to 6 months old babies.

Genetically engineered (recombinant) vaccines are safe because they often use only specific antigens, such as surface proteins from the pathogen, rather than the whole live or killed organism.

Vaccines work by introducing the body to a dead or weakened form of a microbe, allowing the immune system to build antibodies without causing the disease.

Rabies, Anthrax and Cholera vaccines were discovered by Louis Pasteur

Some vaccines contain live, attenuated (weak or inactivated) microorganisms. Although most attenuated vaccines are viral, some are bacterial in nature. Examples include the viral diseases yellow fever, measles, rubella, and mumps, and the bacterial disease typhoid. The live Mycobacterium tuberculosis vaccine contains a virulently modified strain called BCG used to elicit an immune response to the vaccine. The live attenuated vaccine-containing strain Yersinia pestis is used for plague immunization. Rather than introducing an inactivated or attenuated micro-organism to an immune system, a fragment of it (protein subunit) can create an immune response. Examples include the subunit vaccine against hepatitis B virus that is composed of only the surface proteins of the virus, the virus-like particle (VLP) vaccine against human papillomavirus (HPV) that is composed of the viral major capsid protein. 

A vaccine is a biological preparation which provides active acquired immunity to a particular disease. A vaccine contains an agent that resembles a disease-causing microorganism and is often made from weakened or killed forms of the microbe, its toxins or one of its surface proteins. The agent stimulates the body's immune system to recognize the agent as a threat, destroy it and keep a record of it so that the immune system can more easily recognize and destroy any of these microorganisms that it later encounters.

The only available is BCG.
Children it decreases the risk of getting the infection by $20$% and the risk of infection turning into disease by nearly $60$%. tuberculosis is a communicable disease.

Many people could still be at risk of getting a particular disease example polio. This includes those people who have never had the vaccine, those who didn't receive all doses of the vaccine, or those traveling to areas of the world where polio is still prevalent. Therefore, (d) is the correct answer.

• Vaccines are the suspension of weakened or killed microorganism which generates the immune response. 
• It provides active acquired immunity to a particular disease. It is important for both, adults and children, as they can protect us from the many diseases.
  
  

Vaccines are suspensions of killed or weakened microbes or products or derivatives of micro organisms. A vaccine produces immunity to a disease by stimulating the production of antibodies. So, it is always useful.