Vaccination Coverage Assessment

On this page

Vaccination Coverage - Shielding the Masses

  • Definition: Proportion of a defined population (e.g., infants, pregnant women) that has received a specific vaccine or all doses in a schedule.
  • Goal: Achieve high & equitable coverage (typically >90% for Universal Immunization Programme vaccines) to interrupt disease transmission.
  • Importance:
    • Direct protection for vaccinated individuals.
    • Indirect protection for the community via Herd Immunity.
      • Occurs when a critical portion of a community is immunized against a contagious disease, protecting unimmunized individuals.
      • Herd Immunity Threshold: $p_c = 1 - 1/R_0$ (where $R_0$ = Basic Reproduction Number).
      • Example: Measles requires >90-95% coverage for effective herd immunity. Herd immunity diagram: no, low, high vaccination

⭐ The minimum level of immunization coverage needed to achieve herd immunity varies by disease; for measles, it is one of the highest at >90-95% due to its high infectivity ($R_0$ of 12-18).

Assessment Methods - Counting the Shots

Primary method for field assessment:

  • WHO 30x7 Cluster Sampling: Standard for rapid coverage estimation.
    • Objective: Estimate coverage for individual vaccines (BCG, OPV, DPT, Measles, Hepatitis B) & full immunization status.
    • Sample: 30 clusters (villages/wards) × 7 children per cluster = 210 children.
    • Target Age: Typically 12-23 months (assesses timely completion of primary series).
    • Cluster Selection: Probability Proportional to Size (PPS) from a complete sampling frame.
    • Household Selection:
      • Randomly select first household in a cluster.
      • Proceed to nearest households until 7 eligible children are found.
    • Data Sources: Vaccination cards (primary), mother's reliable recall (secondary).

30x7 cluster sampling for vaccination coverage

⭐ The 30x7 cluster sampling method, widely used by WHO, typically provides coverage estimates with a precision of ±10% at a 95% confidence level for the entire sampled area.

Indicators & Interpretation - Reading the Report Card

IndicatorDefinition / Key PointsFormula / Target
Fully Immunized Child (FIC)Child 12-23 months received BCG, OPV (3 doses), DPT/Penta (3 doses), Measles (1st dose).Target: >90% (UIP).
Crude Coverage (Individual Vaccine)Proportion of eligible children receiving a specific vaccine dose. Assesses reach.$(No.\ of\ children\ receiving\ specific\ dose / Total\ eligible\ children) * 100## Indicators & Interpretation - Reading the Report Card

| | Dropout Rate (DOR) | % children starting but not completing multi-dose series (e.g., DPT1 to DPT3). | $((Initial\ Dose\ - \ Final\ Dose) / Initial\ Dose) * 100## Indicators & Interpretation - Reading the Report Card

. Target: <10%. | | Invalid Doses | Doses given too early, too late, wrong interval/route. Reduces true protection. | Not counted in coverage. | | Missed Opportunities (MOV) | Eligible child visits health facility but doesn't receive needed vaccines. System issue. | Identify & reduce. |> ⭐ NFHS-5 (2019-21) reported 76.4% full immunization coverage (12-23 months) in India, highlighting the gap from the >90% UIP target.

Challenges & Solutions - Bridging the Gaps

  • Challenges (Barriers):
    • Operational: Vaccine logistics, cold chain, manpower shortage, AEFI monitoring.
    • Community: Low awareness, misinformation, vaccine hesitancy, migration, cultural beliefs.
    • Geographical: Hard-to-reach areas, difficult terrain.
  • Solutions (Bridging Gaps):
    • Strengthen Service Delivery: Outreach, mobile teams, Reaching Every District (RED).
    • Boost Demand: IEC/BCC, community participation, address hesitancy.
    • Improve M&E: Supportive supervision, data analysis, eVIN, U-WIN.

⭐ Mission Indradhanush (MI) & Intensified Mission Indradhanush (IMI) target unvaccinated/partially vaccinated children (<2 yrs) & pregnant women in high-priority areas. Vaccination Coverage Trends 2000-2022

High‑Yield Points - ⚡ Biggest Takeaways

  • WHO's 30x7 Cluster Sampling is standard for rapid coverage assessment.
  • Lot Quality Assurance Sampling (LQAS) classifies areas by vaccination performance.
  • Coverage Evaluation Surveys (CES) give periodic national/state estimates.
  • Accurate denominator (target children) & numerator (vaccinated) are crucial.
  • Vaccination cards are primary proof; recall/history is secondary.
  • Target >80% routine coverage; >90-95% for measles to achieve herd immunity.
  • Reducing Missed Opportunities for Vaccination (MOV) is vital.

Practice Questions: Vaccination Coverage Assessment

Test your understanding with these related questions

Transmission assessment survey (TAS) is done for which of the following purposes?

1 of 5

Flashcards: Vaccination Coverage Assessment

1/10

If the HCW is unvaccinated and the source is HbsAg -ve, or unknown what is the next step?_____

TAP TO REVEAL ANSWER

If the HCW is unvaccinated and the source is HbsAg -ve, or unknown what is the next step?_____

initiate HB vaccine series

browseSpaceflip

Enjoying this lesson?

Get full access to all lessons, practice questions, and more.

Start Your Free Trial