Table 1.

Descriptive characteristics of included studies investigating the impact of polio supplementary immunisation activities (SIAs), 1994–2020

First author, Publication year	WHO region Country/ies	Setting and population	Main objective	Study design	Study period	Goal of SIA	Author identified study limitations	Funding source and affiliations
Bawa 201837	WHO AFRO Nigeria	Nomadic populations in Northern states of Nigeria	Engagement and immunisation coverage	Cross sectional	2016	To boost coverage in nomadic populations	None reported	WHO 42.8% of authors are affiliated with WHO
Bawa 201932	WHO AFRO Nigeria	Hard to access communities in Bauchi, Borno, Kaduna, Kano, Katsina and Yobe	Effectiveness of mobile outreach strategy	Cross sectional cluster survey Pre–post intervention study	June 2014–September 2015	To boost coverage in hard to reach communities	Data collection were not uniform across sites	Bill and Melinda Gates Foundation 68.2% of authors are affiliated with WHO and Unicef
Bedford 201738	WHO AFRO Liberia	four counties Montserrado, Nimba, Bong, and Margibi	Barriers and drivers for immunisation	Qualitative focus group	May 2015	To boost coverage following disruption in polio vaccine coverage during Ebola virus disease outbreaks	Limited timeframe of data collection Potential language issues during focus groups	No funding declared 57.1% of authors are affiliated with Unicef
Bonu 200311	WHO SEARO India	Rural areas of 4 North Indian states—Bihar, Madhya Pradesh, Rajasthan and Uttar Pradesh	Impact of polio immunisation campaign	Pre–post intervention study Cluster survey	1992–1999 (intervention in 1995)	To boost coverage	The Family Health Survey used was not explicitly designed to evaluate the campaign and unable to discern specific campaign components	No funding declared No affiliations with UN agencies
Bonu, 200412	WHO AFRO WHO SEARO Sub-Saharan Africa Central Africa: Cameroon Western Africa Burkina Faso Cote d’Ivoire Ghana Kenya Niger Nigeria Southern Africa Malawi Zimbabwe Eastern Africa Rwanda Tanzania Uganda South Asia Bangladesh India Nepal	3 South Asian and 12 sub-Saharan African countries with comparable pre–post data, mid-to-lower levels of health system performance	Immunisation coverage and equity	Pre–post intervention study Identified cluster survey Study draws on immunisation data of all the 12–23 months old surviving children at the time of the survey. Hence, crude immunisation coverage was estimated, administered ‘by time of survey’, and based on evidence from card/history.	1990–2001	To boost coverage	No uniformity in preintervention and postintervention surveys between countries Surveys were conducted at different time points Changes cannot be attributed to specific components of the polio eradication initiative	No funding declared No affiliations with UN agencies
Closser, 201439	WHO AFRO WHO SEARO Ethiopia, Nigeria, Rwanda, Angola, India, Nepal, Pakistan	eight districts within seven countries in South Asia and sub-Saharan Africa	Relationship between SIA, routine immunisation and primary healthcare	Quantitative component: Cross-national time series analysis Qualitative component: Case studies including document review, semistructured interview and participant observation	Quantitative: 1990–2010 Qualitative: 2011	Scale up of immunisation activities as part of polio eradication initiative activities	The effects observed in the study were highly context specific and cannot be generalised.	Bill & Melinda Gates Foundation No affiliations with UN agencies
Helleringer, 201640	WHO SEARO Bangladesh	National data	Causal effects of SIA on routine immunisation	Quasi-experimental	2011	To boost coverage	Sample size too small to estimate effect of SIA on routine immunisation Potential reporting error	Unicef 33.3% of authors affiliated with Unicef
Koop, 200141	WHO EURO North Macedonia	Albanian Kosovar refugees in Macedonia Refugee camps in Skopje, Tetovo, and Gostivar regions	Results of extended programme on immunisation	Cross-sectional	May 2011	To boost coverage particularly among refugee populations	No quality control for data collection	No funding declared No affiliations with UN agencies
Levin, 200213	WHO AFRO WHO SEARO Bangladesh Cote d’Ivoire Morocco	Whole countries	Impact of SIA on financing of routine immunisations	Cross sectional	1993–1998	To boost coverage	Non representative countries Did not determine if funding decisions of international agencies were made a t regional or headquarter levels	United States Agency for International Development No affiliations with UN agencies
Mangrio, 200867	WHO EMRO Pakistan	three rural districts and one town—Nawabshah, Sanghar and Mirpurkhas and Malir Town in Karachi city	Healthcare worker views, barriers and driers of routine immunisation	Key informant interviews and focus groups	July–September 2005	To increase routine coverage for polio as part of polio eradication efforts generally	Small scale study	No funding declared No affiliations with UN agencies
Mello, 201042	PAHO/WHO Brazil	27 Brazilian capital cities (including the Federal District)	SIA contribution to routine immunisation coverage	Cross-sectional (household cluster survey)	2007–2008	To boost coverage	Not generalisable results for whole country Inconsistent reasons for non-participation	No funding declared No affiliations with UN agencies
Nsubuga, 201843	WHO AFRO 43 of the 47 countries in the African WHO region (quantitative aspect) Cameroon, Democratic Republic of Congo, Nigeria and Uganda (qualitative aspect)	Entire country	Benefits of polio eradication initiative	Mixed methods	2017	Polio eradication campaigns generally	Recall bias	No funding declared No affiliations with UN agencies
Onyeka, 201444	WHO AFRO Nigeria	Anambra state (South Eastern state)	Lessons from SIAs	Cross sectional	Jan-Nov 2010	To boost coverage	Potential errors in denominator data	No funding declared 25% of authors affiliated with WHO and Unicef
Poy, 201645	WHO AFRO Africa	Case studies of integrated polio SIAs in Cameroon and DR Congo	Impact of polio data management investment on routine immunisation	Descriptive	2001–2014	To boost coverage	Some data management support may have come from non-polio funds	No funding declared 100% of authors affiliated with WHO
Tafesse, 201746	WHO AFRO Ethiopia	Somali region	Effects of SIA on routine immunisation	Descriptive	Jun 2013- Jun 2015	To boost coverage in response to wild-type polio virus outbreak	Data incompleteness	No funding declared 60% of authors affiliated with WHO
van den Ent, 201747	WHO AFRO WHO EMRO WHO SEARO Angola, Chad, DRC, Ethiopia, Nigeria, South Sudan, Afghanistan, Pakistan, Somalia, India	Whole country	Personnel related impact of SIA on routine immunisation	Cross sectional	2013–2014	To boost coverage	Self-reported data has potential for bias	Bill and Melinda Gates Foundation 33.3% of authors are affiliated with WHO
van Turennout, 200368	WHO AFRO South Africa	Dikgale-Soekmekaar district (small rural district)	Routine and mass immunisation coverage	Cross sectional Cluster survey	2000	To boost coverage	Not generalisable to other South African regions	Vlaamse Inter Universitaire Raad No affiliations with UN agencies
Verguet, 201369	WHO AFRO South Africa	52 South African districts	Impact of SIA on routine child and maternal health services	Interrupted time series	2001–2010	To boost coverage	Data quality, non-standardised health records	Bill and Melinda Gates Foundation No affiliations with UN agencies
Wallace, 201748	WHO SEARO Nepal	Central region	Impact of intervention package on routine immunisation	Pre–post intervention	January 2012–September 2013	To boost coverage	No control group Observed practices may not have been representative	Centres for Disease Control and Prevention (CDC) 33.3% of authors are affiliated with CDC and 25% of authors are affiliated with WHO
Zuber, 200370	WHO AFRO Burkina Faso	53 health districts	Compare administrative coverage estimates with cluster survey data coverage	Pre–post intervention Cluster survey	1999	Assessing accuracy of administrative coverage data collected as part of SIAs	Limited sampling	No funding declared 25% of authors are affiliated with CDC 25% of authors are affiliated with WHO