Vaccines
Vaccines are biological preparations that stimulate the immune system (active acquired
immunity) to recognize and combat infectious agents such as bacteria and viruses.
They help in preventing diseases by inducing an immune response without causing the actual
disease.
Vaccines can be classified into several types based on their composition and method of
production.
Conventional Vaccines
Conventional vaccines use whole microorganisms to stimulate an immune response. They can
be classified into:
1. Live Attenuated Vaccines (LAVs)
• Contain weakened (attenuated) but live pathogens that replicate in the body without
causing disease.
• They produce a strong and long-lasting immune response.
• Usually provide lifelong immunity with one or two doses.
Examples
• BCG vaccine (Tuberculosis)
• MMR vaccine (Measles, Mumps, Rubella)
• Oral Polio Vaccine (OPV)
• Yellow Fever vaccine
, Vaccines
Advantages
➢ Strong and long-lasting immunity
➢ Mimics natural infection, stimulating both humoral and cellular immunity
➢ Requires fewer doses
Disadvantages
➢ Risk of reverting to virulent form (e.g., OPV in rare cases)
➢ Not safe for immunocompromised individuals
➢ Requires cold storage.
Vaccines are biological preparations that stimulate the immune system (active acquired
immunity) to recognize and combat infectious agents such as bacteria and viruses.
They help in preventing diseases by inducing an immune response without causing the actual
disease.
Vaccines can be classified into several types based on their composition and method of
production.
Conventional Vaccines
Conventional vaccines use whole microorganisms to stimulate an immune response. They can
be classified into:
1. Live Attenuated Vaccines (LAVs)
• Contain weakened (attenuated) but live pathogens that replicate in the body without
causing disease.
• They produce a strong and long-lasting immune response.
• Usually provide lifelong immunity with one or two doses.
Examples
• BCG vaccine (Tuberculosis)
• MMR vaccine (Measles, Mumps, Rubella)
• Oral Polio Vaccine (OPV)
• Yellow Fever vaccine
, Vaccines
Advantages
➢ Strong and long-lasting immunity
➢ Mimics natural infection, stimulating both humoral and cellular immunity
➢ Requires fewer doses
Disadvantages
➢ Risk of reverting to virulent form (e.g., OPV in rare cases)
➢ Not safe for immunocompromised individuals
➢ Requires cold storage.
