UPSC MainsMEDICAL-SCIENCE-PAPER-II20226 Marks
Q8.

Give two examples for each of the following types of vaccines used in under-5 children:

How to Approach

This question requires a direct and concise answer, demonstrating knowledge of different vaccine types and their specific examples used in pediatric immunization programs. The answer should be structured by first briefly defining vaccine types, then providing two examples for each, focusing on vaccines commonly administered to children under five years of age. Prioritize vaccines included in the national immunization schedule. A clear and organized presentation is crucial for scoring well.

Model Answer

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Introduction

Vaccines are biological preparations that provide active acquired immunity to a particular infectious disease. They work by stimulating the body’s immune system to recognize and defend against pathogens. Vaccination is a cornerstone of public health, significantly reducing the incidence of preventable diseases, particularly in vulnerable populations like young children. The World Health Organization (WHO) recommends a comprehensive immunization schedule for children under five, encompassing various vaccine types. This answer will detail two examples for each of the major vaccine types utilized in this age group.

Live Attenuated Vaccines

Live attenuated vaccines use a weakened (attenuated) form of the virus or bacteria. They create a strong and long-lasting immune response, often requiring only one or two doses. However, they are not suitable for individuals with compromised immune systems.

  • Measles, Mumps, and Rubella (MMR) Vaccine: This combined vaccine protects against three highly contagious viral diseases. It’s typically administered in two doses, the first at 9-15 months and the second at 4-6 years.
  • Oral Polio Vaccine (OPV): While the inactivated polio vaccine (IPV) is now preferred in many countries, OPV continues to be used in some settings for its ability to induce mucosal immunity, aiding in the eradication of polio. It’s administered as multiple doses in infancy.

Inactivated Vaccines

Inactivated vaccines use killed versions of the pathogen. They are safer than live vaccines, as they cannot cause the disease, but generally require multiple doses (boosters) to maintain immunity.

  • Inactivated Polio Vaccine (IPV): Administered via injection, IPV provides protection against polio by stimulating antibody production. It’s part of the routine immunization schedule in many countries.
  • Hepatitis A Vaccine: This vaccine protects against Hepatitis A virus, a liver infection. It’s typically given in two doses, six months apart, starting around one year of age.

Subunit, Recombinant, Polysaccharide, and Conjugate Vaccines

These vaccines use specific parts of the pathogen – like proteins, sugars, or capsules – to trigger an immune response. They are very safe and well-tolerated, but may require adjuvants (substances that enhance the immune response) and boosters.

  • Haemophilus influenzae type b (Hib) Vaccine: This conjugate vaccine protects against Hib bacteria, a common cause of meningitis and other serious infections in young children. It’s administered in a series of doses during infancy.
  • Hepatitis B Vaccine: A recombinant vaccine, Hepatitis B vaccine uses a protein from the Hepatitis B virus to stimulate immunity. It’s typically given as a series of three doses, starting shortly after birth.

Toxoid Vaccines

Toxoid vaccines use inactivated toxins produced by the bacteria. They protect against diseases caused by bacterial toxins, rather than the bacteria themselves.

  • Diphtheria, Tetanus, and Pertussis (DTP) Vaccine: This combination vaccine protects against three serious bacterial diseases. The toxoids neutralize the toxins produced by these bacteria. It’s administered in a series of doses during infancy and early childhood.
  • Tetanus Vaccine (as part of DTP/Tdap): While often combined, tetanus toxoid is a crucial component, providing protection against tetanus, a potentially fatal bacterial infection. Booster doses are recommended throughout life.

Conclusion

In conclusion, a diverse range of vaccine types are employed to protect under-five children from preventable diseases. Live attenuated, inactivated, subunit, toxoid, and conjugate vaccines each offer unique advantages and are strategically utilized within national immunization programs. Continued research and development, alongside effective vaccine delivery systems, are essential to further reduce childhood morbidity and mortality globally and achieve universal immunization coverage.

Answer Length

This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.

Additional Resources

Key Definitions

Adjuvant
An adjuvant is a substance which is added to a vaccine to enhance the body’s immune response to the vaccine. They help to create a stronger and longer-lasting immunity.
Herd Immunity
Herd immunity occurs when a large portion of a community becomes immune to a disease, making the spread of disease from person to person unlikely. This protects individuals who are not immune, such as infants or those with compromised immune systems.

Key Statistics

In 2022, approximately 81% of children worldwide received three doses of the DTP vaccine, indicating a slight decline from pre-pandemic levels.

Source: WHO/UNICEF estimates, 2023

According to UNICEF, in 2021, 23 million children worldwide missed routine vaccinations, a significant increase compared to 2019.

Source: UNICEF, 2022

Examples

Rotavirus Vaccine Impact

The introduction of rotavirus vaccines in many countries has led to a dramatic reduction in hospitalizations and deaths due to rotavirus gastroenteritis, a leading cause of severe diarrhea in infants and young children.

Frequently Asked Questions

Why are booster doses necessary for some vaccines?

Booster doses are needed because the immune response generated by some vaccines can wane over time. Boosters help to “remind” the immune system and restore protective immunity.

Topics Covered

MedicinePediatricsImmunologyVaccinationImmunizationChild Health