About Vaccination


1) What is Vaccination?

Vaccination is the administration of antigenic material (a vaccine) to stimulate an individual's immune system to develop adaptive immunity to a pathogen. Vaccines can prevent or ameliorate morbidity from infection. Vaccination is the most effective method of preventing infectious diseases. Widespread immunity due to vaccination is largely responsible for the worldwide eradication of smallpox and the restriction of diseases such as polio, measles, and tetanus from much of the world.

2) How does Vaccines function?

Generically, the process of artificial induction of immunity, in an effort to protect against infectious disease, works by 'priming' the immune system with an 'immunogen'. Stimulating immune responses with an infectious agent is known as immunization. Vaccination includes various ways of administering immunogens. Most vaccines are given by hypodermic injection as they are not absorbed reliably through the intestines. Live attenuated polio, some typhoid, and some cholera vaccines are given orally to produce immunity in the bowel. While vaccination provides a lasting effect, it usually takes several weeks to develop, while passive immunity (the transfer of antibodies) has immediate effect.

3) What are the different types of vaccination?

Vaccines work by presenting a foreign antigen to the immune system to evoke an immune response, but there are several ways to do this. Four main types are currently in clinical use:

i) An inactivated vaccine consists of virus or bacteria that are grown in culture and then killed using a method such as heat or formaldehyde. Although the virus or bacteria particles are destroyed and cannot replicate, the virus capsid proteins or bacterial wall are intact enough to be recognized and remembered by the immune system and evoke a response. When manufactured correctly, the vaccine is not infectious, but improper inactivation can result in intact and infectious particles. Since the properly produced vaccine does not reproduce, booster shots are required periodically to reinforce the immune response.

ii) In an attenuated vaccine, live virus or bacteria with very low virulence are administered. They will replicate, but locally or very slowly. Since they do reproduce and continue to present antigen to the immune system beyond the initial vaccination, boosters may be required less often. These vaccines may be produced by passaging, for example, adapting a virus into different host cell cultures, such as in animals, or at suboptimal temperatures, allowing selection of less virulent strains, or by mutagenesis or targeted deletions in genes required for virulence. There is a small risk of reversion to virulence, which is smaller in vaccines with deletions. Attenuated vaccines also cannot be used by immuno compromised individuals..

iii) Virus-like particle vaccines consist of viral protein(s) derived from the structural proteins of a virus. These proteins can self-assemble into particles that resemble the virus from which they were derived but lack viral nucleic acid, meaning that they are not infectious. Because of their highly repetitive, multivalent structure, virus-like particles are typically more immunogenic than subunit vaccines. The human papillomavirus (HPV) and Hepatitis B virus vaccines are two virus-like particle-based vaccines currently in clinical use.

iv) A subunit vaccine presents an antigen to the immune system without introducing viral particles, whole or otherwise. One method of production involves isolation of a specific protein from a virus or bacterium (such as a bacterial toxin) and administering this by itself. A weakness of this technique is that isolated proteins may have a different three-dimensional structure than the protein in its normal context, and will induce antibodies that may not recognize the infectious organism. In addition, subunit vaccines often elicit weaker antibody responses than the other classes of vaccines.

4) How Vaccines can be given?

A vaccine administration may be oral, by injection (intramuscular, intradermal, subcutaneous), by puncture, transdermal or intranasal. Several recent clinical trials have aimed to deliver the vaccines via mucosal surfaces to be up-taken by the common mucosal immunity system, thus avoiding the need for injections.

5) What is World Immunization Week?

World Immunization Week is a global public health campaign to raise awareness and increase rates of immunization against vaccine-preventable diseases around the world. It takes place each year during last week of April. Immunization can protect against 25 different infectious agents or diseases, from infancy to old age, including diphtheria, measles, pertussis, polio and tetanus. The World Health Organization (WHO) estimates active immunization currently averts 2 to 3 million deaths every year. However 22.6 million infants worldwide are still missing out on basic vaccines, mostly in developing countries. Inadequate immunization coverage rates often result from limited resources, competing health priorities, poor management of health systems and inadequate surveillance. The goal of World Immunization Week is to raise public awareness of how immunization saves lives, and support people everywhere to get the vaccinations needed against deadly diseases for themselves and their children. World Immunization Week sprung out of the efforts taking place across different countries and regions for a week-long immunization awareness commemoration. World Immunization Week is one of eight official campaigns marked by the WHO.

6) What is Universal Immunization Program(UIP) in India ?

Universal Immunization Programme is a vaccination program launched by the Government of India in 1985. It became a part of Child Survival and Safe Motherhood Programme in 1992 and is currently one of the key areas under National Rural Health Mission (NRHM) since 2005. The program consists of vaccination for seven diseases- tuberculosis, diphtheria, pertussis (whooping cough), tetanus, poliomyelitis, measles and Hepatitis B. Hepatitis B was added to the UIP in 2007. Thus, UIP has 7 vaccine preventable diseases in the program. In 2014 it was announced that four vaccines will be added to the program, namely rotavirus, rubella and Japanese encephalitis, as well as the injectable polio vaccine. Universal Immunization Programme (U.I.P.) is one of the largest in the world in terms of quantities of vaccine used, the number of beneficiaries, the number of Immunization session organized, the geographical spread and diversity of areas covered.

7) What is the Indian scenario in Vaccination?

2.7 Crore children are born in India every year. Approximately 18.3 lakhs children die before their fifth birthday. India records 5 lakh child deaths annually due to vaccine preventable diseases. Despite high childhood mortality rates due to vaccine preventable diseases, 30 percent of Indian children miss the benefits of full immunization every year. That is, an estimated 89 lakhs children across the country that either get only a few vaccines or no vaccines at all. One out of every 3 children in India does not receive all vaccines that are available under UIP. Five percent of children in urban areas and 8 percent in rural areas are unimmunized. The Government of India recognizes immunization as one of the most cost effective interventions to prevent child deaths. India’s Universal Immunization Programme is one of the largest public health interventions in the country with an extensive vaccine delivery system with 27000 vaccine storage units in 35 states across the country. 80% of vaccination takes place in the outreach sessions, held in thousands each year in more than 6 lakh villages and other urban belts.

8) What is Mission Indradhanush?

‘Mission Indradhanush’ was launched on 25th December, 2014 with an aim to cover all those children who are partially vaccinated or unvaccinated. ‘Mission Indradhanush’ is a nationwide initiative with a special focus on 201 high focus districts. These districts account for nearly 50% of the total partially vaccinated or unvaccinated children in the country. Mission Indradhanush will provide protection against seven life-threatening diseases (Diphtheria, Whooping Cough, Tetanus, Polio, Tuberculosis, Measles and Hepatitis B). In addition, vaccination against Japanese Encephalitis and Haemophilus influenza type B will be provided in selected districts of the country. Vaccination against tetanus will be provided to the pregnant women. Between 2009-2013 immunization coverage has increased from 61% to 65%, indicating only 1% increase in coverage every year. To accelerate the process of immunization by covering 5% and more children every year, the Mission Mode has been adopted to achieve target of full coverage by 2020. High-focus 201 districts will be taken up for implementation in the first phase. Of these, 82 districts are in just four states of UP, Bihar, Madhya Pradesh and Rajasthan and nearly 25% of the unvaccinated or partially vaccinated children of India are in these 82 districts of four states. Moreover, 297 will be targeted for the second phase. The Mission focuses on interventions to rapidly increase full immunization coverage of children by approximately 5% annually and to expand full immunization coverage from 65% in 2014 to at least 90% children in the next five years. The government has sought technical support from various external agencies like WHO, UNICEF and Rotary to achieve the goals of this programme. Understandably, the implementation of vaccination programme and ensuring that the benefits of vaccines reach to each and every possible beneficiary is a challenging task. Mission Indradhanush depicting seven colours of the rainbow, aims to cover all those children by 2020 who are either unvaccinated or are partially vaccinated against seven vaccine preventable diseases which include diphtheria, whooping cough, tetanus, polio, tuberculosis, measles and hepatitis B. The Mission Indradhanush initiative is a call for action by the Government of India to intensify efforts to expedite the full immunization coverage in the country. Full immunization will rescues lakhs of children from disease mortality and morbidity and is essential for social development.

9) What are the vaccines schedule under the UIP?

Please click on link “https://kiddohealth.in/vaccination-schedule” to see the vaccination schedule. By providing the date of birth, you can see the exact dates also.