(a) U.S.A.* (excluding Alaska)Geographic area/population Time Number of reported invasive Hia isolates Average annual incidence per 100,000 population Comments Reference White Mountain Apache (east and central Arizona) Oct 1981–Jan 1983 3 out of 18 cases of invasive H. influenzae disease Not reported Prospective surveillance Losonsky et al., 1984 [12 ] Metropolitan Atlanta 1983–1985 5 out of 310 invasive H. influenzae isolates from all hospitals in the greater Atlanta area Not reported 2-year survey of invasive H. influenzae disease Elliott et al., 1990 [21 ] California, New Jersey, Tennessee, Oklahoma, Missouri, Washington (population 33.5 million) Jan–Dec 1986 14 out of 1872 invasive H. influenzae isolates (0.7%) 0.04 Laboratory-based surveillance during time when Hib polysaccharide vaccines were being introduced Wenger et al., 1992 [22 ] San Francisco county 1989–1991 1 out of 12 invasive H. influenzae isolates from adults with HIV infection Not reported Population-based, 3-year active surveillance Steinhart et al., 1992 [23 ] Navajo and White Mountain Apache children <5 years (northern and central Arizona, western New Mexico, southern Utah) 1988–2003 76 cases out of 378 invasive H. influenzae isolates 20.2 for children <5 years; no increase in rates after Hib vaccination was introduced Population-based, active laboratory surveillance data Millar et al., 2005 [24 ] 4 states (Georgia, Tennessee, Maryland, California); population > 10 million 1994–1995 2 cases of Hia out of 18 H. influenzae meningitis Not reported Active, population-based surveillance Schuchat et al., 1997 [25 ] Illinois 1996–2004 8 Hia out of 475 H. influenzae (4/8 in <5 years old) Not reported Retrospective analysis of surveillance data Dworkin et al., 2007 [7 ] Utah children <18 years old 1998–2008 Hia: most prevalent serotype 22 cases/91 invasive H. influenzae disease 28% of cases in children <5 years old In 1998: 0.8 for children In 2008: increased to 2.6 Population-based study In Utah, no Hia in 1991–1998, in 1998-1999: 5 pediatric cases in 10 months, then increased incidence between 1998 and 2008 Bender et al., 2010 [26 ] Utah adults 1998–2008 Hia 15/101 0.08 for adults; no annual changes Population-based study Rubach et al., 2011 [27 ] ABCs (California, Connecticut, Colorado, Georgia, Maryland, Minnesota, New Mexico, Oregon, New York, and Tennessee (11.7% of the US population in 2008) 1999–2008 Hia: 92 (2.2%) of all invasive isolates Not reported Active population- and laboratory-based surveillance conducted through Active Bacterial Core surveillance (ABCs) sites Hia: more frequent cause of invasive disease in American Indian and Alaska Native children compared with nonnative children MacNeil et al., 2011 [28 ]
New Mexico 2009-2010 Cluster of 5 cases in 2009; 7 more sporadic cases in 2009-2010 Not reported ABCs data posted on the website hosted by the Imperial College (UK) http://haemophilus.mlst.net/ [29 ]
Hib conjugate vaccine became available in 1988; in 1991, all infants starting at age of 2 months were recommended to receive the vaccine [30 ].(b) Alaska and Canada**Geographic area/population Time Number of reported invasive Hia isolates Average annual incidence per 100,000 population Comments Reference Alaska residents aged 10 years and older 1980–1996 2/17 of non-type b serotypeable strains Not reported Population-based, descriptive correlational study Perdue et al., 2000 [31 ] IMPACT 12 Canadian pediatric tertiary care centers: nearly 90% of tertiary care pediatric beds in Canada (population 3 million children) 1996–2001 25/166 of invasive H. influenzae isolates from children; 76% of patients with Hia: Aboriginal In the Keewatin Region of Nunavut (2001): 418.8 for Inuit children <5 years; in British Columbia, Alberta, Manitoba, Saskatchewan (1996–2001): 3.7 for Aboriginal children <5 years; 2.3 for Non-Aboriginal children <5 years Retrospective population-based study McConnell et al., 2007 [8 ] Manitoba 2000–2004 26/52 (50%) of invasive H. influenzae isolates Not reported Laboratory-based surveillance Tsang et al., 2006 [32 ] Manitoba 2000–2006 36/122 (29%) of invasive H. influenzae isolates; 72% of Hia cases: children <2 years 0.26 (2000), 0.69 (2001), 0.51 (2002, 2003), 0.34 (2004), 0.59 (2005), 0.16 (2006) Laboratory-based surveillance Tsang et al., 2007 [33 ] Alaska and northern Canada 2000–2005 42/88 of typeable H. influenzae isolates 0.9 (Alaska: 0.3, northern Canada 3.9); 19.7 for children <2 years (Alaska: 5.7, northern Canada: 79.1); 52.6 for indigenous children <2 years (Alaska: 20.9, northern Canada: 101.9) Population-based surveillance Bruce et al., 2008 [34 ] Northern Canada (Yukon, northwestern territories, Nunavut, northern Quebec, and Labrador): population 132,956; 59% Aboriginal 2000–2005 31/59 (59%) cases of invasive H. influenzae disease with serotype information; 73.3% of these in children < 2 years Not reported Population-based surveillance, all Hia cases occurred in Aboriginal persons Degani et al., 2008 [35 ] Ontario 1989–2007 2.1% of 1,455 of invasive H. influenzae isolates 8/284 (2.8%) in children < 2 years; 6/160 (3.75%) in children of 2-10 years Not reported Population-based surveillance Adam et al., 2010 [6 ] Northwestern Ontario (20% Aboriginal population) 2002–2008 13/31 (41.9%) of invasive H. influenzae isolates with serotype information For children < 5 years: 7.7 (2002, 2003, 2008), 15.5 (2006), 23.2 (2004) Population-based surveillance Brown et al., 2009 [36 ] Northwestern Ontario (82% Aboriginal population) 2004–2008 7 cases in First Nations communities 7.0 Population-based surveillance Kelly et al., 2011 [37 ]
British Columbia 2008–2009 10% of 98 invasive H. influenzae isolates; 80% (8/10) in children <2 years Not reported Retrospective laboratory surveillance study Shuel et al., 2010 [38 ] Northern Canada 2000–2010 72 (56% of cases with serotype information) out of 142 invasive H. influenzae cases 4.6 (average incidence over 11 years); 87.5 for children <2 years; 6.9 for Aboriginal people Population-based surveillance Lourenco et al., 2012 [39 ]
In Canada, the first Hib conjugate vaccine became available in 1988 for children older than 18 months of age; the current conjugate vaccine for immunization of infants beginning at 2 months of age was introduced in 1992 [6 ].(c) South AmericaGeographic area/population Time Number of reported invasive Hia isolates Average annual incidence per 100,000 population Comments Reference Sao Paulo (Brazil) 1977–1991 5 out of 1,094 isolates from CSF (0.5%); in comparison, Hib was isolated in 99.4% of cases of meningitis Not reported National surveillance Landgraf and Vieira, 1993 [40 ] Brazil 1990–1999 16 (0.5%) Hia out of 3,204 invasive isolates (prevaccine) Not reported Retrospective study; Hib vaccine was introduced in August 1999 Zanella et al., 2002 [41 ] The metropolitan region of Salvador (northeast Brazil) March 1996–September 2000 13/483 (2.7%) isolates from meningitis. Proportion of Hia cases increased from 5/431 (1.2%) to 8/52 (15.4%) after introduction of routine Hib immunization Prevaccine 0.02; Postvaccine: 0.16 (8-fold increase); In <2 year-old children: increase from 0 to 1.77 Active surveillance for H. Influenzae meningitis cases before and after introduction of Hib immunization Ribeiro et al., 2003 [42 ] Metropolitan Salvador, Brazil August 1996–August 2004 19 out of 25 cases of non-type b H. influenzae meningitis (76%): 4 cases in the pre- and 15 in the postvaccination period Increased from 0.01 to 0.14 in the first year after introduction of vaccine; in children <2 years, increased from 0 to 1.56; during the following 4 years: between 0 and 0.03 Active surveillance for H. influenzae meningitis in children Ribeiro et al., 2007 [43 ] Salvador, Brazil March 1996–September 2007 28/43 (65%) of non-type b H. influenzae meningitis Not reported Active hospital-based surveillance for meningitis Lima et al., 2010 [44 ] Brazil 1990–2008 In 1990–1999: 24/3,050 of H. influenzae meningitis isolates (1%) 2000–2008: 118/860 (14%) Hia meningitis in infants <1 year: 0.31 in 2000–2002; 0.90 in 2003–2005; 1.48 in 2006–2008 Passive laboratory surveillance; retrospective analysis Zanella et al., 2011 [45 ] Cuba 1993–1995 Hia 0.6% of all H. influenzae isolates from meningitis (97% Hib) Not reported Nationwide surveillance Hib conjugate vaccine was introduced in 1999 [46 ] Martínez et al., 1999 [47 ] Colombia 1994–2002 10/683 invasive H. influenzae isolates Not reported Laboratory-based surveillance Hib conjugate vaccine was introduced in 1998 [46 ] Ovalle et al., 2003 [48 ]
19 Latin American and 4 Caribbean countries 2000–2005 131/2,159 (6.1%) invasive H. influenzae isolates Not reported Laboratory-based surveillance Hib vaccine was introduced in Uruguay in 1994, Chile in 1996, Guatemala: 2006, Columbia: 1998 [46 ] Gabastou et al., 2008 [49 ]
(d) AfricaGeographic area/population Time Number of reported invasive Hia isolates Average annual incidence per 100,000 population Comments Reference The Gambia December 1982–January 1984 4 out of 55 cases of H. influenzae meningitis; 3 out of 20 H. influenzae pneumonia Not reported Detection of IS1016-bexA deletion in the encapsulation (cap ) locus of Hia in isolates from 3 cases Kroll et al., 1994 [50 ] The Gambia 1986 (prevaccine) 2 out of 13 invasive H. influenzae isolates; 5 more invasive Hia isolates from the same area Not reported Analysis of lung aspirates from 64 patients with acute lobar pneumonia Wall et al., 1986 [11 ] South Africa Aug 1991–July 1992 (prevaccine) 2 out of 119 invasive H. influenzae isolates from children Not reported One year prospective study in Cape Town children, one septicaemia, one meningitis Hussey et al., 1994 [51 ] South Africa July 1999–June 2004 (post-vaccine) 10/712 invasive H. influenzae isolates (for comparison: Hif 39/712) Not reported National laboratory-based surveillance data, Hib vaccine was introduced in July 1999 Von Gottberg et al., 2006 [52 ] East Africa (Kenya, Uganda, Tanzania, Ethiopia) August 2003–February 2007 16/119 invasive H. influenzae isolates from children between 2 months and 5 years of age Not reported Paediatric Bacterial Meningitis Surveillance Network in the East African Region. Hib vaccine was introduced in Kenya and Uganda in 2001 Mudhune and Wamae, 2009 [53 ]
(e) Papua New Guinea and AustraliaGeographical area/population Time Number of reported cases of Hia disease/isolates Incidence rate Comments Reference Eastern Highlands of Papua New Guinea children <5 years 1978–1988 6.5% (6/92) of blood H. influenzae isolates; 12.3% (9/73) of CSF isolates; 2.9% (1/35) of lung aspirates Not reported Laboratory-based surveillance of acute pneumonia and meningitis in children Gratten and Montgomery, 1991 [54 ] Papua New Guinea March–December 1986 Among 170 adult cases of acute pneumonia, 4/15 of H. influenzae isolates from blood culture or/and lung aspirates Not reported Prospective study of 170 adult patients with acute pneumonia Barnes et al., 1987 [55 ] Papua New Guinea March 1980–September 1984 12% of H. influenzae isolates from children with meningitis (9 strains) Not reported Study of 155 highlands children with bacterial meningitis (2 m–10 y old) Gratten et al., 1985 [10 ] Northern Territory (NT), Australia mid 1985–mid 1988 5 out of 80 of serotyped H. influenzae isolate; all from Aboriginal children; one meningitis Not reported Survey of all invasive H. influenzae infections over a 3-year period in children under 5 years of age at the NT regional hospitals Hanna, 1990 [15 ]
Central Australia Aboriginal population June 1985–May 1986 2/8 of serotyped H. influenzae from Aboriginal children Not reported Population-based surveillance Hansman et al., 1986 [14 ] Central Australia Aboriginal children May 1989–February 1993 Among 77 children with invasive H. influenzae disease <4 years, 7.5% of episodes were caused by Hia (Hib 79% of the isolates) Not reported Population-based study on Aboriginal children hospitalized with invasive disease in Alice Springs, Tennant Creek and Katherine Gratten et al., 1994 [56 ] Australia July 1999–August 2000 4/200 of invasive H. influenzae isolates Not reported Study of antimicrobial susceptibility of H. influenzae isolated from patients with “clinically relevant” conditions, including invasive and noninvasive. Turnak et al., 2001[57 ]
Only few prospective population-based studies have been done and most publications present data from convenient samples. Therefore, not all studies report comparable data, such as the incidence rates.