Long before a vaccination campaign’s cold boxes are packed or its vaccinators trained, someone has to answer a more basic question: how many people live in this district, where exactly are they, and how many teams does it take to reach them all? That process is known in WHO and UNICEF terminology as microplanning — a bottom-up, district- and health-facility-level exercise that turns a national immunization target into a workable local operation. It is unglamorous, spreadsheet-and-map work, but campaigns that skip it or rush it tend to show up later in the coverage data as pockets of unreached children.
What Microplanning Actually Is
Microplanning is associated with the Reaching Every District (RED) strategy, introduced in the early 2000s as a response to immunization programs that looked adequate on paper at the national level but left entire communities unreached. Rather than a plan handed down from a ministry headquarters, a microplan is built by the health workers and district staff who will actually run the campaign, using their own local data to identify where coverage gaps exist and what is standing in the way — distance, seasonal flooding, mistrust, or simply not knowing a settlement is there. The output is a detailed, area-specific roadmap: who is being vaccinated, where, by whom, and with what resources.
Estimating the Target Population
Every other decision in a microplan flows from one number: how many eligible people are in the catchment area. Teams typically start from official census data or, where that is unavailable or outdated, community-level headcounts and local registers. Because campaigns often target children below a certain age, planners also need to estimate the annual cohort of newborns entering the eligible group; a commonly used rule of thumb, when no better local data exists, is to estimate newborns at around 3% of the total population per year. Getting this number wrong in either direction has consequences — underestimate it and vaccine, syringe, and staffing supplies run short mid-campaign; overestimate it and the campaign’s own coverage percentage looks artificially low even when it reached everyone available.
Building the Catchment Map
The second core input is a catchment area map, built or updated at both the district and health-facility level. This is not a general-purpose map but an operational one: it plots every village, settlement, and isolated household the team is responsible for, including groups that are easy to miss in a standard planning exercise — urban poor neighborhoods, migrant or seasonal-worker communities, and newly formed or previously unrecorded settlements. Useful catchment maps also mark roads, tracks, and seasonal barriers such as flood zones that will affect whether a team can physically reach a location on a given week. Community leaders and local administrative officials are typically consulted to confirm boundaries and flag anything the map is missing, and an increasing number of programs supplement this ground-level knowledge with GIS tools and satellite imagery to catch settlements that earlier paper maps overlooked entirely.
Sizing the Vaccinator Teams
With a population estimate and a map in hand, planners can work out staffing: how many vaccination teams a catchment area needs, and how many sessions each will need to run. This is a function of the size and spread of the target population and how often a session can realistically be held in a given location. National guidelines vary, but a workload figure often cited in the field is roughly 30 children per vaccinator per session as a sustainable pace that still allows for proper technique and basic safety checks. Areas with scattered or hard-to-reach populations typically need outreach or mobile teams built into the plan from the start, rather than an assumption that everyone will travel to a fixed post.
Tracking Progress With Tally Sheets
Once the campaign is underway, the tally sheet is the tool that turns the microplan into a feedback loop. Each session’s vaccinator records doses given against the day’s target, which lets a district team see in near real time whether a specific area is falling behind, running low on supply, or missing children who were expected to attend. Paper tally sheets are still the norm in many settings, but they are slow to aggregate and can delay a correction by days; a growing number of campaigns are piloting digital, real-time reporting specifically to shorten that lag so a shortfall in one catchment area can be addressed before the campaign moves on rather than after it ends.
The Microplan as a Whole
None of these four elements works in isolation. A population estimate without a catchment map cannot tell a team where to actually deploy; a staffing ratio without accurate tally data cannot tell a district whether it planned correctly. The table below summarizes how the pieces fit together.
| Microplan input | Typical data source | What it drives |
|---|---|---|
| Target population | Census or community headcount, plus an annual newborn estimate | Vaccine, syringe, and supply quantities |
| Catchment boundaries | Local maps, community leader input, increasingly GIS/satellite imagery | Where teams are deployed and how often |
| Vaccinator staffing | Population size and spread divided by a per-session workload | Number of teams and fixed vs. outreach sessions |
| Progress tracking | Daily tally sheets, paper or digital | Mid-campaign correction of gaps and shortfalls |
For a desk that has covered mass-immunization logistics from the cold chain to field supply, microplanning is worth treating as its own subject rather than a footnote to those topics. It is the step where a campaign’s ambitions on paper either translate into an accurate operational plan or quietly fail to, well before any vaccine reaches an arm.