Immunization Coverage Survey

EPI and WHOImmunization Coverage Survey:

For the Assessment ofCoverage by the Meningitis vaccine and the infant routine immunization, in seven states in

Sudan- 2013

Muna Hassan Mustafa

Background

• Sudan is one of the countries in the meningitis belt and is prone to meningococcal meningitis epidemics

• The last major epidemic in Sudan in 1999 resulted in 33,313 cases and 2,386 deaths.

• Reactive vaccination campaigns using polysaccharide vaccines was the main measure to combat epidemics

Background

• These campaigns faced many challenges as a result of late implementation and high campaign costs

• new meningococcal A conjugate vaccine was introduced that has several advantages over the existing polysaccharide vaccines

• WHO promotes a strategy for vaccinating all 1-29 year-olds in the African meningitis belt

Background

• the new meningococcal A conjugate vaccine was introduced to Sudan in 2012 in 10 states as the first phase.

• Phase two (october 2013) targeted the remaining seven states in Sudan, namely, Kassala, White Nile, Northern, River Nile, Red Sea, S&N Kordofan states.

• Accurate vaccination coverage estimates are critical for programmatic evaluation, identification of under-vaccinated subpopulations, and for measurement of the impact of the new vaccine

Objectives– General Objective:

• to assess the coverage by meningococcal meningitis vaccine and the routine childhood immunization coverage and the reasons behind failure to receive the vaccines, in Seven states in Sudan – 2013

– Specific Objectives:• To determine the proportion of individuals (1-29 years old) who received the

new conjugate vaccine during the second phase of implementation in seven states in Sudan – 2013

• To identify the reasons behind the failure to receive the meningococcal meningitis vaccine during the second phase of implementation in seven states in Sudan – 2013

• To determine the proportion of children (aged 12 -23 months) who are fully immunized by the time of the survey against the targeted childhood diseases in seven states in Sudan – 2013

• To identify the reasons behind the failure to receive the vaccines against the targeted childhood diseases in seven states in Sudan – 2013

Survey main indicators

• The proportion of individuals 1-29 years old who received the meningococcal Meningitis vaccine during the second immunization campaign 2013 in the respective state.

• The proportion of children 12-23 months old who are fully immunized by the time of the survey in the respective state.

Materials and Methods

– Study design: cross-sectional, community-based survey.– Study Area: the survey will cover the seven states that

are targeted by phase two of the vaccine implementation plan.

– Study population: individuals from both with the following inclusion criteria:• In the age group 1 to 29 years old at the time of the

vaccination campaign. • Were present in the respective state during the vaccination

campaign. • Had not received the vaccine during the first vaccination

campaign in October 2012


Sampling:1. Sample size:

• Meningococcal meningitis vaccination coverage: assuming a significance level of 5%, or confidence level of 95%, desired level of precision of ± 3, expected immunization coverage of 90%,a design effect of 2 and a non response rate of 10% .

• The survey will target 30 clusters in each state • The number of individuals to be selected from each cluster

will be 29. • The sample size will be divided between the three age strata

as follows

Age group % of age group 1-29 years

Cluster size

1 – 4 years 21.2 7

5- 14 years39.4

11

15 -29 years39.4

11

Total 100

29

Thus the total sample size from each state will be 29 x 30 = 870 participants.


• Childhood routine immunization coverage: • Assuming a significance level of 5%, or confidence

level of 95%, desired level of precision of the estimates of ± 10, expected immunization coverage of 80% and a design effect of 2. T

• The survey will target 30 clusters in each state • The number of individuals to be selected from each

cluster will be 7. • Thus the total sample size from each state will be 7 x

30 = 210 children.


2. Sampling technique: • The survey will use a stratified cluster sampling

technique. • EPI population frame will be used as the

sampling frame • For assessing the meningococcal meningitis

vaccination coverage three strata will be defined by the three age groups of the participants(1 – 4 years old, 5- 14 years old and 16-29 years old)


• Selection of Popular Administrative Unit (PAU): • Thirty PAUs will be selected from each frame using the

probability proportional to size technique • The cluster size is:

– 7 for children 12 -23 months old – 7 for children 1- 4 years old, – 11 for children 5-14 years – 11 for individuals 15 -29 years.

Age group % of Sudan total population

Required population size

Required number of households*

12 – 23 months 3 93 161 – 4 years 15 187 315 -14 years 28 100 1715 -29 years 28 100 17

* The required population size divided by 6 (the average household size in Sudan)

This means that at least 31 house are needed to obtain the cluster size from each PAU. This will be rounded to 50 houses


• Selection of houses: All the houses in each of the 50-house selected segments will be visited after selecting the first one randomly

• If more than one household occupy the house, all of them should be interviewed


• Selection of participants:• Meningococcal meningitis vaccination

coverage: if more than one individuals are in targeted age groups one should be selected randomly

• Childhood routine immunization coverage: If there is more than one child in the household between 12 and 23 months, the youngest is to be included


• If the 50-house segment is completed before fulfilling the cluster size for any of the age groups, it should be completed from the nearest 50-house segment


• Data collection: – Technique: face-to-face interviews with eligible

participants or their care takers– Tools:– Meningococcal meningitis vaccination coverage:

a structured form (Meningococcal meningitis vaccination coverage cluster form) adapted from the WHO standard tools


• Childhood routine immunization coverage: • Two structured forms adapted from the WHO

standard tools:– Infant immunization cluster form– Reasons for infant immunization failure cluster

form


• Pilot study: • Whether the questions are understandably

phrased;• Duration to locate the participants and

duration of interview


• Implementing a quality control system on data: – The first level - the interviewers:– The second level - the field supervisor: – The third level – the national supervisor:– The fourth level the office editors in Khartoum:


• The field work teams: • From each cluster area, the data will be

collected by a fieldwork team consisting of 2 sub-teams of interviewers under the supervision of a field supervisor.

• Each sub-team team will be composed of two interviewers


• Duration of the fieldwork: it is expected that a team will complete a cluster in one day.

• Thus 5 teams will need 6 days to cover the 30 clusters in each state.


• Data processing and analysis:• The data entry and analysis will be through the Excel

workbook template designed by the WHO for the immunization coverage cluster survey data

• It will be slightly adapted for the meningococcal meningitis vaccination coverage survey.

• Proportions of participants who received any type of vaccine will be calculated along with 95% confidence interval.

• the proportion of participants who failed to immunize due to any one specific reason will be calculated along with the 95% confidence interval


• Ethical issues: • The protocol is be submitted for ethical clearance

by the National Ethical Clearance Committee.• The survey will be conducted in accordance with

the national policies on ethics for surveys involving human

• Verbal informed consent will be sought• All the information will be anonymous and

congeniality will be insured

Survey Team

• State supervisors : Overseeing the implementation of the survey (technical side) and the quality of data

• State co-coordinator: Overseeing the implementation of the survey (logistics)

• Field supervisor: supervising the data collection and quay of data at cluster level

• Interviewers: data collection

Survey Team

• Data editors: review and edit the completed forms

• Data entry clerks: data entry• Statistician: sample selection and data

analysis

Activity time frame Month 1 Month 2

Finalize protocol and nomination of survey team members

Selection of primary sampling units

Pilot study

TOT (state coordinators and state supervisors and office editors)

Preparation fieldwork logistics

Recruiting fieldwork teams

Training of the fieldwork teams

Preparation of fieldwork logistics(state)

Arrange the travel and accommodation for the state supervisors

Data collection

Supervising the fieldwork operation

Office editing

Data entry

Data analysis

Report writing

GANTT Chart:

Documents

Immunization Coverage Survey