Routine immunization coverage in Pakistan: a survey of children under 1 year of age in community-based vaccination areas

Exploring the path to polio eradication: insights from consecutive seroprevalence surveys among Pakistani children

Introduction

After trivalent oral poliovirus vaccine (tOPV) cessation, Pakistan has maintained immunity to type 2 poliovirus by administering inactivated polio vaccine (IPV) in routine immunization, alongside monovalent OPV type 2 (mOPV2) and IPV in supplementary immunization activities (SIAs). This study assesses the change in poliovirus type 2 immunity after tOPV withdrawal and due to SIAs with mOPV2 and IPV among children aged 6-11 months.

Methods

Three cross-sectional sequential serological surveys were conducted in 12 polio high-risk areas of Pakistan. 25 clusters from each geographical stratum were selected utilizing probability proportional to size.

Results

Seroprevalence of type 2 poliovirus was 49%, with significant variation observed among surveyed areas; <30% in Pishin, >80% in Killa Abdullah, Mardan & Swabi, and Rawalpindi. SIAs with IPV improved immunity from 38 to 57% in Karachi and 60 to 88% in Khyber. SIAs with IPV following mOPV2 improved immunity from 62 to 65% in Killa Abdullah, and combined mOPV2 and IPV SIAs in Pishin improved immunity from 28 to 89%. Results also reflected that immunity rates for serotypes 1 and 3 were consistently above 90% during all three phases and across all geographical areas.

Conclusion

The study findings highlight the importance of implementing effective vaccination strategies to prevent the re-emergence of poliovirus. Moreover, the results provide crucial information for policymakers working toward achieving global polio eradication.

The Enterics for Global Health (EFGH) Shigella Surveillance Study in Pakistan

Background

The Enterics for Global Health (EFGH) Shigella surveillance study is a longitudinal multicountry study that aims to estimate incidence rates and document consequences of Shigella diarrhea within 7 countries in Africa, Asia, and Latin America. In addition to a high incidence of childhood diarrhea, Pakistan is facing a problem of antimicrobial resistance in urban and peri-urban areas of Karachi.

Methods

In Pakistan, EFGH will be conducted in Karachi, which is one of the metropolitan cities bordering the Arabian Sea and has a diverse population of 1.6 million according to the 2017 population census. The study aims to enroll 1400 children aged 6-35 months over 2 years (2022-2024) from 6 health care facilities (Abbasi Shaheed Hospital, Khidmat-e-Alam Medical Centre, Sindh Government Hospital Korangi 5, Sindh Government Hospital Ibrahim Hyderi, Ali Akbar Shah VPT Center, and Bhains Colony VPT Center) situated in Nazimabad and Bin-Qasim town. Moreover, population enumeration and health care utilization surveys from a defined catchment area of health facilities will be conducted to estimate the Shigella diarrhea incidence rates.

Conclusions

The study will provide critical data to policy-makers about the burden of Shigella and antimicrobial resistance, which is essential for planning Shigella vaccine trials.

Determinants of immunization in polio super high-risk union councils of Pakistan

BACKGROUND

The current polio epidemiology in Pakistan poses a unique challenge for global eradication as the country is affected by ongoing endemic poliovirus transmission. Across the country, 40 union councils (UCs) which serve as core reservoirs for poliovirus with continuous incidences of polio cases are categorized as super-high-risk union councils (SHRUCs).

METHODOLOGY

A cross-sectional survey was conducted in 39 SHRUCs using a two-stage stratified cluster sampling technique. 6,976 children aged 12-23 months were covered. A structured questionnaire was used for data collection. Data were analyzed using STATA version 17.

RESULTS

Based on both vaccination records and recall, 48.3% of children were fully-, 35.4 % were partially-, and 16.3% were non-vaccinated in the SHRUC districts. A child is considered fully vaccinated when h/she completed vaccination for BCG, OPV0, OPV 1-3, Penta 1-3, PCV 1-3, IPV, and MCV1. Vaccination cards were seen for over half of the children in the SHRUC districts of Khyber Pakhtunkhwa (KP) and the majority of the SHRUC districts in Sindh, except for the SHRUC district of Malir the districts of Balochistan. Results for polio vacancies show that 60.9% of children from the SHRUC districts were vaccinated with at least three doses of OPV and one dose of IPV, while 20.4% were vaccinated with any OPV doses or IPV and 18.7% of children did not receive any polio vaccines. The dropout rate between vaccine visits was higher than the WHO-recommended cutoff point of 10% for all vaccine doses in the SHRUC districts. The likelihood of being fully vaccinated was higher among the children of educated parents. Full vaccination was found significant among the children of any SHRUC districts compared to district Killa Abdullah.

CONCLUSION

Context-specific strategies with more focus on community engagement and targeted mobilization, along with robust monitoring mechanisms, would help address the underlying challenges of under-immunization in the SHRUCs.

Factors Associated with Vaccine Refusal (Polio and Routine Immunization) in High-Risk Areas of Pakistan: A Matched Case-Control Study

BACKGROUND

Pakistan has subpar childhood immunization rates and immunization activities have faced several challenges over the past years. We evaluated the social-behavioral and cultural barriers and risk factors for refusal of polio, Routine Immunization (RI), or both in high-risk areas of poliovirus circulation.

METHODS

A matched case-control study was conducted from April to July 2017 in eight super high-risk Union Councils of five towns in Karachi, Pakistan. A total of 3 groups, each with 250 cases, including refusals for the Oral Polio Vaccine (OPV) in campaigns (national immunization days and supplementary immunization activities), RI, and both, were matched with 500 controls and identified using surveillance records. Sociodemographic characteristics, household information, and immunization history were assessed. Study outcomes included social-behavioral and cultural barriers and reasons for vaccine refusal. Data were analyzed in STATA using conditional logistic regression.

RESULTS

RI refusal was associated with illiteracy and fear of the vaccine's adverse effects, while OPV refusals were linked to the mother's decision authority and the assumption that the OPV caused infertility. Conversely, higher socioeconomic status (SES) and knowledge of and willingness to vaccinate with Inactivated Polio Vaccine (IPV) were inversely associated with RI; and lower SES, walking to the vaccination point, knowledge of IPV, and an understanding of contracting polio were inversely associated with OPV refusals, with the latter two also inversely associated with complete vaccine refusal.

CONCLUSION

Education, knowledge and understanding of vaccines, and socioeconomic determinants influenced OPV and RI refusals among children. Effective interventions are needed to address knowledge gaps and misconceptions among parents.

Is vaccine confidence an unexpected victim of the COVID-19 pandemic?

Vaccines are among the safest and most effective primary prevention measures. Thanks to the synergistic global efforts of research institutions, pharmaceutical companies and national health services, COVID-19 vaccination campaigns were successfully rolled out less than a year after the start of the pandemic. While the unprecedented speed of development and approval of COVID-19 vaccines has been applauded as a public health success story, it also spurred considerable controversy and hesitancy even amongst individuals that did not previously hold anti-vaccination stances. This study aimed to compare pre- and post-pandemic vaccine confidence trends in different demographic groups by analysing the outcomes of two online surveys run respectively in November 2019 and January 2022 involving a total of 1009 participants. Non-parametric tests highlighted a statistically significant decline in vaccine confidence in the 2022 cohort compared to the 2019 cohort, with median Vaccine Confidence Score dropping from 22 to 20 and 23.8% of participants reporting that their confidence in vaccines had declined since the onset of the pandemic. While the majority of internal trends were comparable between the two surveys with regards to gender, graduate status and religious belief, vaccine confidence patterns showed considerable alterations with regards to age and ethnicity. Middle-aged participants were considerably more hesitant than younger groups in the 2019 cohort, however this was not the case in the 2022 survey. In both surveys White participants showed significantly higher vaccine confidence than those from Black backgrounds; in the 2022 cohort, unlike the pre-pandemic group, Asian participants showed significantly lower confidence than White ones. This study suggests that paradoxically, despite the success of COVID-19 vaccination campaigns, vaccine confidence has significantly declined since the onset of the pandemic; the comparison of a pre- and post-pandemic cohort sheds light on the differential effect that the pandemic had on vaccine confidence in different demographic groups.

Age-appropriate vaccination coverage and its determinants in children aged 12-36 months in Nepal: a national and subnational assessment

Background

Vaccination is one of the effective ways to develop immunity against potential life-threatening diseases in children in early age. This study is focused on analysing the age-appropriate vaccination coverage at national and subnational levels and identify the factors associated with age-appropriate coverage in Nepal.

Methods

460 children aged 12–36 months were included in the study. The data was obtained from Nepal Demographic and Health Survey (NDHS) 2016–17. Age-appropriate coverage of Bacillus Calmette-Guerin vaccine (BCG), oral polio vaccine (OPV) doses 1–3, pentavalent vaccine (PE) doses 1–3, and first dose of measles, mumps, and rubella vaccine (MMR) were estimated using Kaplan Meier method. Multilevel logistic regression with random intercept was used to identify the factors associated with age-appropriate vaccination.

Results

The crude coverage of the vaccines included in the study ranged from 91.5% (95% CI, 88.5–93.7) for PE3 to 97.8% (95.8–98.7) for BCG. Although the crude coverage of all the vaccines was above 90%, the age-appropriate coverage was significantly low, ranging from 41.5% (36.5–46.6) for PE3 to 73.9% (69.2–78.1) for PE1. Furthermore, high disparity in timely vaccination coverage was observed at regional level. Compared to the age-appropriate vaccination coverage in other provinces, Province 2 had the lowest coverage of all, followed by that in Province 6. The timeliness of vaccination was significantly associated with subnational regions i.e., provinces and the season of childbirth.

Conclusion

Although the immunization program in Nepal has achieved the target of 90% crude coverage of all the childhood vaccines, the age-appropriate coverage is significantly low which undermines the effectiveness of the vaccines administered. Thus, along with crude coverage, timeliness of the vaccines administered should be taken into consideration and thoroughly monitored at national and subnational levels. Provincial government should formulate tailored strategies to ensure the timely administration of the childhood vaccines.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11841-2.

Characteristics of mobile phone access and usage among caregivers in Pakistan - A mHealth survey of urban and rural population

INTRODUCTION

Globally mobile ownership and access is becoming very common, and breakthroughs in mobile technology have shaped digital communication, with 7 billion mobile phone users globally. Developing countries account for 80% of newly purchased mobile phone devices with majority of such countries having low Routine Immunization coverage and a high risk of vaccine preventable diseases. The use of mobile phones provides a tremendous potential for public health involvement.

OBJECTIVE

The aim of this study is to assess the acceptability and usability of mobile phones among infant caregivers in a LMIC setup and to explore the role of mHealth to improve immunization uptake and coverage.

METHODS

This is a cross-sectional survey exploring the regional differences in mobile phone ownership, usability and preferences, along with level of trust with others while sharing a mobile phone. The study was conducted with caregivers of infants in an urban and rural sites of Pakistan.

RESULTS

A total of 4472 households were approached, of which 3337 participants were eligible for the study (74.61 %). The reasons for not participating in the study (n = 1135) included (i) household locked or refusal to participate for 594 families (52%), (ii) child older than 14 days of life in 409 cases (36%), (iii) 80 (7%) families did not have access to a functional mobile phone, (iv) 36 (3%)families did not provide a mobile phone number, and (v) 14 (1%) could not stay within the HDSS for 6 months. Access to mobile phone with SMS features was considerably high at both sites: 99.1% in Matiari (rural site) and 96.7% in Karachi (urban). In Matiari 96.6% of the respondents reported having daily access to the phone, contrasting with only 51.4% in Karachi. In Karachi, the predominant spoken language was Urdu, whereas majority of the respondents in Matiari spoke Sindhi (34.6% vs. 70.9%).

CONCLUSION

Our study indicates high access to mobile phone in both urban and rural setup, However access to smart phone is still limited, urban and rural setup. Further, the acceptance of overall health- and barrier-based child immunization messages through mobile phone were quite high in both settings. Lastly automated calls were preferred over SMS due to literacy and local settings. This bears important implications for improving child immunization uptake through mobile phones in developing regions such as Pakistan.

Evaluating the vaccination coverage: validity of household-hold vaccination booklet and caregiver's recall

BACKGROUND

We compared results from household data sources to medical record sources by using data from a vaccination coverage survey.

METHODS

Vaccination coverage (VC) was calculated based on parental recall, household vaccination booklet, and Zhejiang provincial immunization information system (ZJIIS). We evaluated the accuracy of VC based on household sources (vaccination booklet and recall) assuming the medical record was accurate. Concordance, sensitivity, specificity, positive predictive value, and negative predictive value were estimated as well as the Kappa statistic was also used to evaluate the agreement between data sources.

RESULTS

Among the 1,800 children identified in the household survey, all were registered in ZJIIS. VC estimated using the vaccination booklet alone was substantially lower than that based on medical records (net bias 3.4-16.7% in different age groups). VC based on parental recall ranged from 2.5% below (among children aged 1 year) to 16.7% points above (among children aged 6 years) than those based on medical records. Concordance was lowest for card estimates (32.5-45.5%). Sensitivity was <60% for all household sources, except for recall source. Specificity was lowest for recall estimates (14.5-42.6%). Positive predictive value was >75%, while negative predictive value was <50%, for all household sources. Kappa statistics generally indicated poor agreement between household and medical record sources.

CONCLUSIONS

Household-retained vaccination booklets and parental recall were insufficient sources for evaluating the VC. Our findings emphasized the importance of taking interventions to make the vaccination booklet more consistent with the records from medical resource.

Quantifying movement patterns and vaccination status of high risk mobile populations in Pakistan and Afghanistan to inform poliovirus risk and vaccination strategy

BACKGROUND

Stopping serotype 1 wild poliovirus transmission in Pakistan and Afghanistan requires ensuring all children <5 years of age are repeatedly vaccinated, including the large proportion living in mobile groups. Vaccinating children living in high-risk mobile populations (HRMPs) remains a priority for the polio programme.

METHODS

In 2017-2018, group-level censuses were conducted in 43 districts of Pakistan, gathering information for all HRMP children <5 years of age residing in settlements. Demographic and mobility information was collected, including HRMP type, ethnicity, language, mode of transportation and movement patterns. Vaccination status was recorded for the most recent polio campaign. Proportion of HRMP children by demographic factors and mode of transportation was determined and the magnitude of movement was quantified based on the origin, previous and next locations. Magnitude of cross-border movement with Afghanistan was evaluated, as was primary crossing point. Vaccination status was evaluated for each district by demographic and mode of transportation information.

RESULTS

In total, 188,130 HRMP children <5 years of age were assessed. The predominant HRMP type, ethnic group, language and mode of transport was Afghan refugees (27%), Pashtun (69%), Pashto (69%) and bus (52%). Overall, 84% of children originated outside of their current district, including 29% from Afghanistan. Previous and next locations, were reported outside of current location by 34% and 77% of children. Afghanistan was previous and next location for 5% and 11% of children, with 5.5% and 3% of children crossing the Afghanistan border in the past 6-months and next 3-months. Primary crossing route was Torkham (79%). Overall vaccination coverage was 98% (IQR: 96%-99%) and consistently >90% across HRMP type, ethnic group, language and mobility means.

CONCLUSION

Large numbers of HRMPs were found across Pakistan, with substantial links throughout the country and with Afghanistan. While vaccination coverage of HRMPs was high, ensuring these populations are consistently vaccinated remains a priority.