Vaccination vs Immunisation: Expert Explains If They Are Really the Same?

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A new mother in Howrah recently found herself Googling a question thousands of Indian parents quietly wonder about after every clinic visit: didn't my child just get vaccinated, so why isn't she "immune" yet? It's a mix-up that plays out in paediatric wards and WhatsApp parenting groups alike, and it points to a gap in understanding that goes well beyond semantics.

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Vaccination and immunisation are often used as if they mean the same thing. They don't, and the difference matters, especially when it comes to knowing what to expect from a jab, and when.

We spoke to Dr Shubhadeep Das, Senior Consultant and Clinical Lead: Pediatric Cardiac ICU/ PICU/ Paediatrics, Narayana Hospital, Howrah, who explained how immunisation is different from vaccination and what you should know.

Vaccination vs Immunisation

"Vaccination is the act of administering a vaccine by injection, orally, or through the nasal route. In contrast, immunisation is the broader process by which a person develops protection against a disease, usually following vaccination," said Dr Das.

Vaccines work by safely exposing the immune system to an antigen, or instructions for making an antigen, so that it learns to recognise and respond to a specific pathogen. "Importantly, vaccines do not always prevent infection completely; their major benefit is reducing the risk of infection and, in particular, severe disease, complications, hospitalisation, and death," added Dr Das.

Different Types of Vaccines

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• Live-attenuated vaccines contain weakened forms of a virus or bacterium capable of producing a strong immune response without causing disease in healthy individuals. The MMR vaccine is a common example.
• Inactivated vaccines contain killed organisms that cannot replicate or cause infection. Examples include the inactivated polio vaccine (IPV) and hepatitis A vaccine.
• Subunit, recombinant, polysaccharide and conjugate vaccines contain selected components of a pathogen, such as proteins or polysaccharides, rather than the whole organism. Examples include hepatitis B, pneumococcal and Hib vaccines.
• mRNA vaccines use messenger RNA to instruct our cells to temporarily produce a harmless antigen, which stimulates an immune response. The mRNA does not alter a person's DNA and is subsequently broken down by the body.

Immunisation: Building Protection Against Disease

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"Following vaccination, the immune system recognises the vaccine antigen as foreign and activates specialised immune cells, including B and T lymphocytes. B cells can produce antibodies, while both B- and T-cell responses contribute to immune memory. If the person encounters the actual pathogen later, the immune system can respond more rapidly and effectively," explained Dr Das.

Vaccination and immunisation have dramatically reduced the burden of diseases such as polio, measles, rubella, mumps, diphtheria, tetanus, pertussis, hepatitis A and B, pneumococcal disease and rotavirus infection. Vaccination against human papillomavirus (HPV) can also prevent persistent HPV infection and substantially reduce the risk of cervical cancer and several other HPV-related cancers.

Message From The Expert

Dr Das highlighted, "It is important, however, to recognise that immunity is not necessarily lifelong. The duration of protection varies between vaccines and diseases. Some vaccines provide long-lasting protection, while others require multiple doses or boosters to maintain adequate immunity."

Bottomline

Dr Das concluded, "Vaccination is the intervention; immunisation is the development of protection that follows. Vaccination not only protects individuals but, when sufficiently widespread, can also reduce transmission and protect vulnerable members of the community."

Staying up to date with recommended vaccines across childhood and adulthood therefore remains one of the most effective measures available for preventing infectious diseases and their complications.

Disclaimer: The information provided in this article is for general informational and educational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or a qualified healthcare provider with any questions you may have regarding a medical condition.