Vaccination Coverage in Pakistan Muhammad Farooq Umer1, Shumaila Zofeen1, Wenbiao Hu2, Xin Qi1,3* & Guihua Zhuang1*
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www.nature.com/scientificreports OPEN Spatiotemporal clustering analysis of Expanded Program on Immunization (EPI) vaccination coverage in Pakistan Muhammad Farooq Umer1, Shumaila Zofeen1, Wenbiao Hu2, Xin Qi1,3* & Guihua Zhuang1* Universal vaccination coverage is still far from desired targets in many global regions including Pakistan, despite the success stories and its scientifcally proven benefts. EPI Pakistan vaccination coverage data 2012–2016, at district level was collected from Federal EPI Pakistan. District-wise population data were collected from Pakistan Bureau of Statistics. Descriptive statistics and sequence plots were performed in SPSS 13.0. Purely spatial scanning analysis was done in SaTScan 9.4.4 using discrete Poisson model for detection of low vaccination coverage clusters. Geographical information system (GIS) was used to display spatial patterns and clusters of low vaccination coverage districts in Pakistan. Average annual EPI vaccination coverage in each study year were; 70.98 in 2012, 69.39% in 2013, 66.74% in 2014, 61.47% in 2015, and 67.01% in 2016, respectively. Cumulative average national vaccination rate (2012–2016) for all types of EPI vaccines was 60.60%. Average national vaccination rate for BCG, OPV3, pentavalent3 and measles1 was 67.12%, 58.53%, 58.47%, and 58.29%, respectively. Spatial cluster analysis demonstrated that most of low coverage districts for BCG, OPV3 and pentavalent3 were from FATA and KPK; while measles1 low coverage districts belonged to Balochistan. Future research should probe factors involved in low vaccination coverage in high risk districts. Abbreviations BCG Bacillus Calmette Guerin DTP Diphtheria tetanus pertussis EPI Expanded program on immunization FATA Federally Administered Tribal Areas GIS Geographical Information System KPK Khyber Pakhtunkhwa NADRA National Database Authority Pakistan OPV Oral polio vaccine PDHS Pakistan Demographic and Health Survey PSLM Pakistan social and living standards measurement survey UNICEF United Nations Children Fund VR Vaccine rate vLMIS Vaccine Logistics Management Information System WHO World Health Organization Te invention of and advancements in the childhood vaccination has revolutionized human healthcare and facilitated to averting morbidity and mortality from many vaccine-preventable infectious diseases 1. Immuniza- tion not only has helped preventing life-threatening diseases but also beneftted mankind by increasing their life expectancy (life span has increased by 15 to 25 years since the commencement of vaccines) and in improving 1School of Public Health, Xi’an Jiaotong University Health Science Center, Xi’an 710061, China. 2School of Public Health and Social Work, Queensland University of Technology, Kelvin Grove, QLD 4059, Australia. 3Global Health Institute, Xi’an Jiaotong University Health Science Center, Xi’an 710061, China. *email: [email protected]; [email protected] SCIENTIFIC REPORTS | (2020) 10:10980 | https://doi.org/10.1038/s41598-020-67839-0 1 Vol.:(0123456789) www.nature.com/scientificreports/ Vaccination type 2012 2013 2014 2015 2016 BCG 6,002,983 6,093,216 6,087,530 5,825,405 6,217,308 OPV3 5,307,855 5,365,150 5,340,132 5,243,034 5,370,649 Pentavalent3 5,255,236 5,378,442 5,338,499 5,213,164 5,363,685 Measles1 5,428,966 5,602,642 5,354,079 5,185,488 5,444,831 Table 1. Number of vaccinated children for each EPI vaccination type in Pakistan, 2012–2016. quality of life2,3. However, these successes cannot mask the failures in shape of millions of deaths of the unvac- cinated children annually, across the globe4. Estimated 1.5 million children died of vaccine-preventable diseases in each of 2013 and 2017 respectively which construes that the world could have avoided an additional huge number of deaths a year had the universal immunization coverage achieved 5,6. Despite the fact that overall vaccination coverage in 2018 remained around 86%6, there remained a wide disparity between diferent World Health Organization (WHO) regions, e.g., the Americas, Europe and West- ern Pacifc maintained over 90% immunization coverage of DTP3 containing vaccine whilst these rates were low for most of the countries in Africa and some in Asia 7. Low levels of immunization coverage in the low-and middle-income countries pose a serious challenge to achieving universal vaccination coverage goals8,9. For any child to develop adequate immunity against the particular disease, adherence to complete vaccination schedule is of critical importance, as, incomplete vaccination leads to partial immunity and the disease risk persists10,11. Tere have been fatal outbreaks of vaccine-preventable infectious diseases in the developing countries which refect the presence in large numbers of non-and under-vaccinated children12,13. As a matter of fact, the bottom- most ten countries with lowest vaccination coverage belonged to either low or lower-middle income group 7. Approximately 19.4 million eligible children did not receive DTP3 dosage worldwide—around 40% (8 million) of these children lived in war-aficted areas 6. In Pakistan, government patronage for vaccination coverage through the Expanded Programme on Immu- nization (EPI) has been there for decades yet the low coverage areas have been stubbornly in existence across the country14. Tis has increased vulnerability to vaccine preventable diseases and not surprisingly Pakistan has been amongst countries with highest mortality and morbidity rates in children under 5 years of age 15,16. Under-5 deaths make nearly half of all the deaths in Pakistan, which is around 8 to 10% of all deaths in the developed countries17. Pakistan has the lowest vaccination coverage statistics amongst the sub-continent countries (Bangla- desh, Sri Lanka and India)18. Tese neighbouring countries had also overcome their respective indigenous polio transmission since 2011 through their massive scale high quality vaccination campaigns 18–20, unlike Pakistan which is still struggling with Polio endemicity (along with Afghanistan and Nigeria)21. Statistics from diferent sources in Pakistan have reported varying percentages of vaccination coverage, rang- ing from 40 to 80% with wide variations between provinces as well as between male and female children 22. Te higher percentages for vaccination coverage are generally reported by the government while some researchers and non-governmental agencies have reported low vaccination coverages across Pakistan over the time23–25. Tis variation may be attributed to the methodology adopted in collection of data (recall/record base data, estimation of the numerators/denominators), over/miss-reporting of the collected data, training/skill of the feld teams and some other socio-geographical factors (parents’ knowledge, religious beliefs and accessibility to health facility). EPI is virtually the exclusive provider of immunization services in Pakistan, conducting around 97% of the total immunization activities in the country. EPI in Pakistan vaccinates more than 5 million children under 1 year of age annually, in order to provide them protection against eight vaccine preventable infectious diseases through its routine immunization services 26. Vaccination coverage with third dose of diphtheria, pertussis and tetanus (DTP3) is a commonly used indicator for the routine immunization services’ performance of various countries; whereas, Bacillus Calmette Guerin (BCG), third dose of oral polio vaccine (OPV3), pentavalent3 (containing DTP3) and Measles1 are considered to be yardstick of completed vaccination schedule 27. Terefore, this study did not discuss rest of the vaccines which are included in EPI Pakistan routine immunization schedule but are further than the criteria of labelling a child as fully immunized (e.g. for Haemophilus Infuenzae, Meningitis, Rota virus, Pneumonia and 2nd dose of Measles). Epidemiologists have been interested in the geographical clustering of diseases 28 and other public health prob- lems such as communities with non/low vaccination 29. Low vaccination coverage areas tend to exist in clusters and spatial scan statistics are an important tool to detect them for their subsequent targeting by the concerned authorities29. Tere are only few studies available on vaccination coverage discussing country-wide data and even scarce studies using modern statistical methods (e.g., spatial analysis) in Pakistan. Te available data on vaccination coverage in Pakistan is limited and on many occasions faulty and over-estimated30. Te available studies on vaccination coverage either discuss secondary data from surveys across Pakistan or are about one or few districts and predominantly about single antigen25,31–33. Our study has tried to contribute in these lacking areas of spatial analysis on vaccination coverage across Pakistan. Results Total number of children vaccinated in each year (2012 to 2016) and for each vaccination type are shown in Table 1. SCIENTIFIC REPORTS | (2020) 10:10980 | https://doi.org/10.1038/s41598-020-67839-0 2 Vol:.(1234567890) www.nature.com/scientificreports/ Quantiles Year Vaccine type Mean Std. deviation Minimum 25 50 75 Maximum BCG 70.89 15.94 24.53 62.52 73.77 80.64 98.02 OPV 3 62.38 14.73 17.56 56.61 67.11 71.21 93.62 2012 Pentavalent 3 62.09 14.58 17.56 56.58 65.81 70.51 93.62 Measles 1 62.17 16.16 15.80 54.16 66.55 74.75 87.93 BCG 69.34 15.18 8.02 63.35 73.07 78.94 97.69 OPV 3 60.29 15.70 3.98 55.31 65.53 70.52 96.23 2013 Pentavalent 3 60.55 15.29 5.34 55.31 65.56 70.63 96.23 Measles 1 61.46 17.29 6.10 52.40 67.16 72.94 95.34 BCG 66.83 15.81 10.98 59.93 71.46 76.70 97.87 OPV 3 57.46 16.25 1.27 51.31 62.78 70.08 92.70 2014 Pentavalent 3 57.47 16.18 3.82 51.34 62.78 70.10 92.70 Measles 1 57.18 16.82 5.68 47.43 61.76 70.46 80.51 BCG 61.79 16.10 3.55 54.47 66.12 73.23 95.14 OPV 3 55.83 16.11 1.77 48.47 60.97 67.48 85.79 2015 Pentavalent 3 55.63 15.94 1.77 48.47 60.97 66.99 85.79 Measles 1 54.48 17.57 2.51 42.52 59.78 68.33 84.48 BCG 67.14 14.37 18.19 57.48 71.02 76.70 97.47 OPV 3 57.61 14.56 5.83 49.32 61.42 68.11 87.60 2016 Pentavalent 3 57.57 14.54 4.82 49.32 61.42 67.77 87.60 Measles 1 57.55 16.33 7.50 47.28 61.72 69.92 92.39 Table 2.