First author (year) | Location | World Bank country income group* | WHO region† | Study design | Time period | Pandemic or seasonal influenza | Reported LCI outcomes | |||
LCI illness in ambulatory care settings | LCI hospitalisation | LCI ICU admission | LCI death | |||||||
Ali (2016)34 | Sindh Province, Pakistan | Lower-middle income | Eastern Mediterranean Region | Surveillance | October 2011 to June 2014 | Seasonal | ✔ | |||
Ampofo (2006)26 | Salt Lake City, Utah, USA | High income | Region of the Americas | Retrospective cohort | July 2001 to June 2004 | Seasonal | ✔ | ✔ | ✔ | |
Bennet (2016)43 | Stockholm, Sweden | High income | European Region | Retrospective cohort | 1998–1999 to 2013–2014 | Pandemic H1N1 and seasonal | ✔ | |||
Bhat (2005)7 | USA | High income | Region of the Americas | Surveillance | September 2003 to May 2004 | Seasonal | ✔ | |||
Broor (2014)35 | Haryana State, India | Lower-middle income | South-East Asia Region | Surveillance | August 2009 to July 2011 | Pandemic H1N1 and seasonal | ✔ | ✔ | ||
Budge (2014)37 | Department of Cajamarca, Peru | Upper-middle income | Region of the Americas | Prospective cohort | May 2009 to September 2011 | Pandemic H1N1 and seasonal | ✔ | |||
Cohen (2016)38 | Gauteng Province, KwaZulu-Natal Province, Mpumalanga Province, South Africa | Upper-middle income | African Region | Surveillance | January 2010 to December 2013 | Seasonal | ✔ | |||
Cox (2012)27‡ | USA | High income | Region of the Americas | Surveillance (EIP) | April 2008 to April 2010 | Pandemic H1N1 and seasonal | ✔ | |||
Dawood (2010)28 | USA | High income | Region of the Americas | Surveillance (EIP) | 2003–2004 to 2007–2008 | Seasonal | ✔ | ✔ | ||
Griffin (2004)29§ | Davidson County, Tennessee; Hamilton County, Ohio; and Monroe County, New York, USA | High income | Region of the Americas | Surveillance (NVSN) | 2000–2001 to 2003–2004 | Seasonal | ✔ | |||
Grijalva (2006)30§ | Davidson County, Tennessee, USA | High income | Region of the Americas | Surveillance (NVSN and EIP capture–recapture study) | 2003–2004 | Seasonal | ✔ | |||
Grijalva (2007)31§ | Davidson County, Tennessee; Hamilton County, Ohio; and Monroe County, New York, USA | High income | Region of the Americas | Surveillance (NVSN and EIP capture–recapture study) | 2004–2005 | Seasonal | ✔ | |||
Iwane (2004)32§ | Davidson County, Tennessee; Monroe County, New York; USA | High income | Region of the Americas | Surveillance (NVSN) | 2000–2001 | Seasonal | ✔ | ✔ | ||
Ji (2010)39 | Jiangsu province, China | Upper-middle income | Western Pacific Region | Surveillance | Jan 2007 to December 2008 | Seasonal | ✔ | ✔ | ||
Libster (2010)40 | Buenos Aires, Argentina | Upper-middle income | Region of the Americas | Case series | May 2009 to July 2009 | Pandemic H1N1 | ✔ | ✔ | ✔ | |
Madhi (2014)16 | Soweto, South Africa | Upper-middle income | African Region | RCT | 2011 to 2012 | Seasonal | ✔ | ✔ | ✔ | |
McMorrow (2015)36 | Nairobi and Lwak, Kenya | Lower-middle income | African Region | Surveillance | January 2008 to December 2012 | Pandemic H1N1 and seasonal | ✔ | |||
Montes (2005)11 | Regions of Basque Country, Spain | Upper-middle income | European Region | Retrospective cohort | July 2001 to June 2004 | Seasonal | ✔ | ✔ | ||
Nelson (2014)44 | Hong Kong (China) | High income | Western Pacific Region | Retrospective cohort | April 2005 to March 2011 | Pandemic H1N1 and seasonal | ✔ | ✔ | ||
Poehling (2006)9§ | Davidson County, Tennessee; Hamilton County, Ohio; and Monroe County, New York, USA | High income | Region of the Americas | Surveillance (NVSN) | 2000–2001 to 2003–2004 | Seasonal | ✔ | ✔ | ✔ | |
Poehling (2013)8§ | Davidson County, Tennessee; Hamilton County, Ohio; and Monroe County, New York, USA | High income | Region of the Americas | Surveillance (NVSN) | 2004–2005 to 2008–2009 | Seasonal | ✔ | |||
Proff (2009)33 | Colorado, USA | High income | Region of the Americas | Surveillance | 2004 to 2008 (1 October to 31 May annually) | Seasonal | ✔ | |||
Silvennoinen (2011)45 | Finland | High income | European Region | Retrospective cohort | July 1988 to June 2004 | Seasonal | ✔ | ✔ | ||
Stein (2010)46 | Israel | High income | European Region | Prospective cohort | 12 July 2009 to 24 December 2009 | Pandemic H1N1 | ✔ | ✔ | ||
Tapia (2016)17 | Bamako, Mali | Low income | African Region | RCT | 12 September 2011 to 28 January 2014 | Seasonal | ✔ | ✔ | ✔ | |
Yu (2014)41 | Jingzhou City, Hubei Province, China | Upper-middle income | Western Pacific Region | Surveillance | April 2010 to April 2012 | Seasonal | ✔ | |||
Zhang (2016)42 | Suzhou District, China | Upper-middle income | Western Pacific Region | Surveillance | April 2011 to March 2014 | Seasonal | ✔ | |||
Total=27 studies | 6 | 23 | 7 | 9 |
*World Bank. World Development Indicators. Accessed: 10 January 2017. Available at: http://data.worldbank.org/data-catalog/world-development-indicators.
†WHO regional offices. Accessed: 10 January 2017. Available at: http://www.who.int/about/regions/en/.
‡Although the study objective was to report data from the 2009 H1N1 influenza pandemic, the reported incidence rates were from other years for comparison. As the incidence rates from 2008 to 2009 have not been reported elsewhere, they have been included.
§Surveillance was conducted from 1 November to 30 April each year, but the time period was extended if influenza was detected earlier or ended later.
EIP, Emerging Infections Program; ICU, intensive care unit; LCI, laboratory-confirmed influenza; NVSN, New Vaccine Surveillance Network; RCT, randomised controlled trial.