Ultimate Guide to Immunization in Children—Importance, Schedule and Side Effects

What is Immunization and vaccination?

Immunization is a process in which the body is strengthened against certain infection by the means on inoculating/injecting a portion of antigen to evoke the natural immune system to prepare against the infection.

Vaccination refers to the actual process of injecting or inoculating the antigen called as ‘immunogen’, while the body’s response in fortifying the body by producing antibodies is called as immunization. However, both the terms are usually used interchangeably.

Which diseases are prevented by immunization?

As of now there are nine diseases that are covered under routine immunization in children.

  • Diphtheria, called as rohini in Hindi
  • Pertussis or whooping cough, kali khansi in Hindi
  • Tetanus, Dhanustambha in Hindi
  • Poliomyelitis, Bahutrisha in Hindi
  • Mumps, Kanapheṛa or Galasua in Hindi
  • Measles, Khasara in Hindi
  • Rubella,
  • Hepatitis B, Yakrtasotha or Peelia in Hindi
  • Haemophilus influenzae type b (Hib)
  • Typhoid

Why must every child be immunized?

First of all, immunization directly protects the children from contracting serious infections (for which vaccines are available). Once immunized it is unlikely that the child will suffer from that disease even if there is an outbreak in the community. What else can be a better reason to get your child immunized than keeping the child safe?

Secondly, one the entire community is immunized against the common pathogens, the infection can no longer prevail in the community. Not only it stops spreading, but gradually dies out completely. It is because of immunization that small pox has been eradicated from the world, and polio is eliminated from many countries.

What is the mechanism of immunization?

Whenever someone (mostly children) is injected or swallows a vaccine, his/her body responds by evoking an immune response against the vaccine in a manner similar to the actual exposure of the pathogen, only the vaccine is too weak to contract the actual disease. When the person comes in contact with the disease’s pathogen naturally, the body is already prepared for it and the immune response is fast enough to prevent the disease from making its impact.

What is the content of a vaccine?

The content of vaccine differs from vaccine to vaccine. Some vaccine contains a little dose of a live, accentuated (weakened) form of a virus. Other vaccines may contain a very minute dose of killed bacteria or minute parts of the bacteria. Many other vaccines contain a little dose of a modified toxin produced by the bacteria. Few vaccines can contain aluminium salt that aids in better immune response. Some may also contain a little amount of antibiotic or preservative to preserve the vaccine.

How much time does it take for the Immunization to work?

Commonly it takes up to several week for the immunization to affect the immunity. It means that the child is still unsafe from the infection until complete immunity sets in. Some vaccines needs multiple doses separated at a gap of several months. If the child hasn’t received all the doses yet, the child is only partially immunized against the disease for example in diphtheria, pertussis and tetanus. They may still contract the disease.



Does Immunization protect everyone the same way?

Well, not really. The effect of immunization varies between individuals and everyone is not protected even after vaccination. The success rate is higher in mumps, measles, rubella, polio, tetanus, hepatitis B and Hib vaccines, with success in up to 95% of the children who completed the regime. Success rate in whooping cough is about 85% who received all three doses.

Do the Immunizations lasts forever?

Not necessarily. It varies from vaccine to vaccine. For example, tetanus vaccine may be effective for up to 30 years and after that booster doses should be given regularly. On the other hand, vaccine for pertussis is effective for up to five years after a completed regime.

Why are there so many vaccinations?

In first few years of life, especially during infancy a child’s immune system is most vulnerable. Though, in breastfeeding infants, antibodies are passed from mother to the baby and provides some protection, later when the antibody levels wear off, the baby is again vulnerable to infection. Thus, a number of immunizations ensure that the children remain safe from infections during the most crucial years of their life.

What are the potential side effects of vaccinations?

Soreness and redness at the injection side are very common side effects. In majority of children mild fever is also seen. Though, these symptoms may seem upsetting to both you and your child, in the long term it protects the child from possible serious infections. Sometimes a small dose of paracetamol may be require to alleviate the fever and tenderness.

If your child falls severely ill, or has any other symptoms other than soreness and mild fever, you should immediately seek medical help from a pediatrician.

Recommended Immunization Schedule in India


Age  Disease  Vaccination  Remarks 
At birth Hepatitis B Hep B vaccine –I
Polio Oral PV 0 dose
Birth to 6 weeks Tuberculosis BCG
4 -6 weeks Hepatitis b Hep b Vaccine -II
6 weeks Diphtheria, Pertussis, Tetanus DPT-I
Polio OPV-I
10 weeks Diphtheria, Pertussis, Tetanus, , Dpt-II, ,
Polio OPV-II
Hepatitis B Hep B Vaccine III* *Delhi Govt. Recommendation
14 weeks Diphtheria, Pertussis, Tetanus Dpt-III
Hepatitis B Hep B Vaccine IV* *Delhi Govt. Recommendation
24 weeks Hepatitis B Hep B Vaccine III* *IAP recommendation
9 -12 mths Polio OPV-IV
Measles Measles
15-18 mths Mumps, Measles, Rubella MMR* *Recommended by Delhi Govt. & IAP only
18 mths Diphtheria, Pertussis, Tetanus DPT Booster-I
Polio OPV-V
24 mths Typhoid Typhoid* *IAP Recommendation
4-5 yr Diphtheria, Pertussis, Tetanus DPT Booster – II
Polio OPV-VI



  1. http://www.nevdgp.org.au/info/immunisation/whatis_immunisation.htm
  2. http://www.ima-india.org/page.php?page_id=42