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Supplementary Immunization Activity (SIA) Data

In this section Svea Closser describes data collected from campaigns and how they are interpreted. (Step 3.6)
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SVEA CLOSSER: So polio eradication’s largest, most extensive activity is conducting polio campaigns for every child under 5 in large portions of sub-Saharan Africa and South Asia. These are enormous projects that require millions of workers vaccinating most of the children in the world multiple times a year. So they collect a lot of data on the efficacy of this, because it’s through these campaigns that polio would get eradicated. So today, we’re going to talk about two kinds of data that are collected through campaigns. First, we’re going to talk about tally sheets, or the records that vaccinators keep as they go door to door vaccinating children. And we’re also going to talk about post-campaign monitoring.
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And this is another system that’s used to understand how good was coverage in the last campaign. The first example I want to bring you– and again, this is a slide from polio eradication itself– is a slide from Indonesia looking at campaign coverage data during a nationwide campaign in Papua and West Papua provinces in 2019. And as you can see, there’s maps for each round of this campaign. And for each map, you have different parts of the country labeled green, yellow, or red. So what this means is that in red areas, there was less than 60% coverage with polio vaccine. In the dark green, there was greater than 95%.
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So if you were a polio eradicator looking at these maps, what would this sort of campaign coverage data tell you? And what steps would you take based on this? The answer here is a little more obvious than some of the other maps we’ve been looking at. In this case, the areas that are red are areas that have low vaccination coverage. And you might want to go back and perhaps redo a subnational campaign in those areas, or go look more closely at what was going on to leave you with less than 60% coverage in this campaign. That coverage is not high enough to eradicate polio probably.
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So in addition to just seeing for example, how many children recovered in a given area, polio eradication has developed a series of process indicators that they can use to understand the reasons why coverage in a certain area might be higher or lower. So here’s an interesting one. This particular slide is from 2005 in Pakistan. And what we have here are three maps of Pakistan. And what they’re showing is the percent of missing children recorded. So this is a little bit of a complicated data point. So let’s talk through this for a minute.
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When a vaccination team goes door to door, what they do is they write down information on how many children were in the house, how many of them were vaccinated, and the reasons that any children were missed. These might be because a kid wasn’t at home, maybe they were visiting their grandparents, maybe they were sick and the parent was concerned that they didn’t want their kid to get a vaccine when they were sick and they should come back later. Incidentally, that is not really a concern. There’s no risk to giving a sick child polio vaccine. But it is something that many parents are concerned about, or maybe the parents were full on refusals.
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In any of those cases, the vaccination team is supposed to write down on their tally sheet but they couldn’t vaccinate the child and the reason why. So what this map shows is overall with all the teams tally sheets taken together, what percent of children on those tally sheets were recorded as missed. And you can see in the red areas of the country what the teams told their supervisors on their tally sheets was that over 95% of children were at home and vaccinated when they came to the house. So this is a process indicator that you can use to understand maybe how thorough a team is being.
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If a team claims that more than 95% of the kids were at home and were vaccinated the first time they came by, this is generally an indication that they’re trying to cut corners. Recording a missed child means you have to go back to cover it. So it’s more work for the vaccination teams. But it’s really not generally the case that more than 95% of children are going to be at home the first time you visit their house. So understanding how many more children are being recorded is a way of understanding how good your coverage actually is through somewhat of an indirect means. This information can be used in a lot of ways.
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You can use this to think about, what are areas where we might need to provide more training or support or supervision for vaccination teams? Maybe what are the reasons that teams aren’t recording all of the children that are missed? Now when you think more deeply about it, what could be the downsides or difficulties of using this information? Take a minute to think about that.
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So as it turns out vaccination teams learned quite quickly that this indicator, percent of most children recorded, was important and that the cutoff was 5%. So it actually resulted in some cases in vaccinators manipulating the data in their favor. So you can’t always necessarily rely on indicators like this. Instead, you need to go out and check sample areas to actually know the truth. Here’s another process indicator from Pakistan in 2005. This is another map of Pakistan. And this one shows the percentage of vaccination teams that had at least one female. So this was really important, it still is very important in much of the world.
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And in much of Pakistan, it’s actually not particularly acceptable for unrelated men to go inside a house to go vaccinate a child. Women, on the other hand, are welcome into most houses. So women have much, much better access to small children, especially to newborn babies who generally are not allowed outside of the house in some areas. So having a woman on the vaccination team is a critical piece of getting inside the house and getting to all the kids that are needed. But in much of the country, over half of the vaccination teams didn’t have a woman on the team. So this was an important process indicators.
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So collecting data on this was a way that polio eradication officials tried to think about what are some of the reasons we might be missing children and what can we do about it. So overall, there’s a lot of data that comes out of campaigns, both in terms of coverage, but also in terms of process. And thinking about analyzing and presenting this data has been a way that polio eradication has tried to improve campaign coverage overall. So to take this example of this slide we’re looking at right now, the percentage of teams with at least one female in Pakistan in 2019, about 15 years later, is much, much higher.

Svea Closser, MPH, PhD
Bloomberg School of Public Health, Johns Hopkins University, USA

Reflect on the case study in Pakistan, where the vaccination teams claimed that more than 95% of children were at home and were vaccinated the first time they visited the home. Since it is highly unlikely that percentage of children are at home during the first visit, much less vaccinated, it seems likely that the data is inaccurate. Consider the following questions:

  • What are areas where we might need to provide more training or support or supervision for vaccination teams?
  • What are some possible reasons that teams aren’t recording all of the children that are missed?
  • What could be the downsides or difficulties of using this information?

Please take a moment to post your thoughts in the discussion.

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Collecting and Using Data for Disease Control and Global Health Decision-Making

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