Monitoring vaccination coverage: Defining the role of surveys.

Vaccination coverage is a widely used indicator of programme performance, measured by registries, routine administrative reports or household surveys. Because the population denominator and the reported number of vaccinations used in administrative estimates are often inaccurate, survey data are often considered to be more reliable. Many countries obtain survey data on vaccination coverage every 3-5years from large-scale multi-purpose survey programs. Additional surveys may be needed to evaluate coverage in Supplemental Immunization Activities such as measles or polio campaigns, or after major changes have occurred in the vaccination programme or its context. When a coverage survey is undertaken, rigorous statistical principles and field protocols should be followed to avoid selection bias and information bias. This requires substantial time, expertise and resources hence the role of vaccination coverage surveys in programme monitoring needs to be carefully defined. At times, programmatic monitoring may be more appropriate and provides data to guide program improvement. Practical field methods such as health facility-based assessments can evaluate multiple aspects of service provision, costs, coverage (among clinic attendees) and data quality. Similarly, purposeful sampling or censuses of specific populations can help local health workers evaluate their own performance and understand community attitudes, without trying to claim that the results are representative of the entire population. Administrative reports enable programme managers to do real-time monitoring, investigate potential problems and take timely remedial action, thus improvement of administrative estimates is of high priority. Most importantly, investment in collecting data needs to be complemented by investment in acting on results to improve performance

Third-Party Verification Immunization Coverage Survey (TPVICS) - 2021

• Background• Survey Design and Methodology• Implementation of Survey• Survey Results• Referenceshttps://ecommons.aku.edu/pakistan_coe-wch_survey_report/1000/thumbnail.jp

2023 Supplementary Immunization Coverage Survey in Super High Risk Union Councils of Pakistan (TPVICS-SHRUCs Rounds 1-3)

• Background and Objectives• Survey Design and Methods• Survey Results• Behavioral and Social Drivers of Vaccination (BeSD)• Discussion• Referenceshttps://ecommons.aku.edu/pakistan_coe-wch_survey_report/1002/thumbnail.jp

Characteristics of common surveys used to measure vaccination.

<p>PPES, probability proportional to estimated population size.</p

Gridded population survey sampling: a systematic scoping review of the field and strategic research agenda

IntroductionIn low- and middle-income countries (LMICs), household survey data are a main source of information for planning, evaluation, and decision-making. Standard surveys are based on censuses, however, for many LMICs it has been more than 10 years since their last census and they face high urban growth rates. Over the last decade, survey designers have begun to use modelled gridded population estimates as sample frames. We summarize the state of the emerging field of gridded population survey sampling, focussing on LMICs.MethodsWe performed a systematic scoping review in Scopus of specific gridded population datasets and "population" or "household" "survey" reports, and solicited additional published and unpublished sources from colleagues.ResultsWe identified 43 national and sub-national gridded population-based household surveys implemented across 29 LMICs. Gridded population surveys used automated and manual approaches to derive clusters from WorldPop and LandScan gridded population estimates. After sampling, some survey teams interviewed all households in each cluster or segment, and others sampled households from larger clusters. Tools to select gridded population survey clusters include the GridSample R package, Geo-sampling tool, and GridSample.org. In the field, gridded population surveys generally relied on geographically accurate maps based on satellite imagery or OpenStreetMap, and a tablet or GPS technology for navigation.ConclusionsFor gridded population survey sampling to be adopted more widely, several strategic questions need answering regarding cell-level accuracy and uncertainty of gridded population estimates, the methods used to group/split cells into sample frame units, design effects of new sample designs, and feasibility of tools and methods to implement surveys across diverse settings

Illustrative questions used in the past to elicit a verbal history of vaccination according to the EPI schedule in the 1980s.

<p>DTP, diphtheria toxoid, tetanus toxoid, and whole cell pertussis vaccine combination; OPV, oral polio vaccine.</p

Schematic of recording of vaccination data at the time of vaccination and during community surveys.

<p>Recording at the time of vaccination (primary recording) is indicated in black boxes; recording during surveys is indicated in green boxes. Main potential sources of information error and bias are highlighted in blue. DOB, date of birth.</p

World Health Organization–recommended EPI schedule, 2012.

<p>Adapted from <a href="http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.1001404#pmed.1001404-World9" target="_blank">[67]</a>.</p>a<p>Since perinatal or early postnatal transmission is an important cause of chronic infections globally, all infants should receive their first dose of hepatitis B vaccine as soon as possible (<24 hours) after birth even in low-endemicity countries. The primary hepatitis B immunization series conventionally consists of three doses of vaccine (one monovalent birth dose followed by two monovalent or combined vaccine doses at the time of DTP1 and DTP3 vaccine doses). However, four doses may be given for programmatic reasons (e.g., one monovalent birth dose followed by three monovalent or combined vaccine doses with DTP vaccine doses), according to the schedules of national routine immunization programs.</p>b<p>OPV alone, including a birth dose, is recommended in all polio-endemic countries and those at high risk for importation and subsequent spread. A birth dose is not considered necessary in countries where the risk of polio virus transmission is low, even if the potential for importation is high/very high.</p>c<p>For infants, three primary doses (the 3p+0 schedule) or, as an alternative, two primary doses plus a booster (the 2p+1 schedule). If the 3p+0 schedule is used, vaccination can be initiated as early as 6 weeks of age with an interval between doses of 4–8 weeks. If the 2p+1 schedule is selected, the two primary doses should ideally be completed by 6 months of age, starting as early as 6 weeks of age with a minimum interval of 8 weeks between the two doses (for infants aged ≥7 months a minimum interval of 4 weeks between doses is possible). One booster dose should be given at 9–15 months of age.</p>d<p>If Rotarix is used, only two doses are administered.</p>e<p>In countries that have achieved a high level of control of measles, the initial dose of measles vaccine can be administered at 12 months of age. All children are currently expected to receive a second dose of measles vaccine. In the least developed countries this is often administered through mass immunization campaigns.</p>f<p>Rubella vaccine, administered in combination with measles vaccine, is recommended for countries that reliably administer two doses of measles vaccine and have achieved a high level of measles control.</p>g<p>Yellow fever should be co-administered at the infant visit when measles vaccine is administered.</p>h<p>Japanese encephalitis vaccines may be given at age 12 months for children living in highly endemic areas.</p><p>DTP, diphtheria toxoid, tetanus toxoid, and whole cell pertussis vaccine combination; HBV, hepatitis B vaccine; Hib, <i>Haemophilus Influenzae</i> type b conjugate vaccine; OPV, oral polio vaccine; pentavalent combination, DTP+HBV+Hib formulated to be administered in combination as a single injection; PnCV, pneumococcal conjugate vaccine containing either 10 or 13 separate conjugates of different capsular serotypes.</p

Main potential sources of error and strategies to minimize them in population-based surveys measuring vaccination coverage.

<p>Main potential sources of error and strategies to minimize them in population-based surveys measuring vaccination coverage.</p