Oral polio vaccine is a?

NCL (MP) Nursing Officer - 2019

Applied Microbiology & Infection control

Easy

Appeared in: NCL (MP) Nursing Officer - 2019

Explanation

The Oral Polio Vaccine (OPV), or Sabin vaccine, contains live but weakened (attenuated) strains of the poliovirus.
Upon oral administration, these weakened viruses replicate in the intestine, stimulating a robust immune response.
This process induces both local immunity in the gut (secretory IgA) and systemic immunity in the blood (humoral antibodies), providing comprehensive protection.
The ability to induce local gut immunity is a key feature that helps in creating 'herd immunity' by preventing the spread of wild poliovirus in the community.

Option B: A 'killed vaccine' contains viruses that have been inactivated and cannot replicate. This describes the Inactivated Polio Vaccine (IPV or Salk vaccine), not the oral polio vaccine.
Option C: 'Freeze-dried' (lyophilized) is a method of preparing and preserving a vaccine to make it more stable, not a fundamental type of vaccine based on its biological content. While some live vaccines like BCG and measles are freeze-dried, this is not the primary classification for OPV.
Option D: A 'recombinant vaccine' is produced using recombinant DNA technology, where a specific gene from a pathogen is inserted into another organism to produce antigens. OPV is created by attenuating the whole virus, not through genetic engineering.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Classification of vaccines based on their composition and mechanism as background academic context rather than a clinical decision trigger.
A critical nursing responsibility is managing the 'cold chain' for OPV, as it is heat-sensitive. It must be stored at -20°C for long periods and 2-8°C for short-term use. The Vaccine Vial Monitor (VVM) on the vial must be checked before administration to ensure potency.
OPV's ability to confer 'herd immunity' is a major public health advantage. The shed vaccine virus can passively immunize close, unvaccinated contacts, helping to quickly stop community transmission during outbreaks.
Nurses must screen for contraindications. OPV should not be given to individuals with primary immunodeficiency diseases or to household contacts of immunocompromised persons due to the risk of the vaccine virus causing disease.

How to Approach the Question

First, identify the key term in the question stem: 'Oral polio vaccine'.
This is a factual recall question that requires knowledge of vaccine classifications.
Recall the different types of vaccines: live attenuated, killed/inactivated, toxoid, and recombinant.
Categorize the Oral Polio Vaccine (Sabin vaccine) based on your knowledge. Remember that it is given orally and designed to mimic natural infection to build immunity.
Contrast this with the Inactivated Polio Vaccine (Salk vaccine), which is a killed vaccine given by injection.
Select the option that correctly classifies the oral polio vaccine as a live vaccine.

Concept Tested & Keywords

Concept Tested: Classification of vaccines based on their composition and mechanism.
Stem keywords: Oral polio vaccine, vaccine
Lead-in keywords: is a

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