2008 Georgia data summary: haemophilus influenzae and haemophilus influenzae type B (hib) disease

2008 Georgia Data Summary:
Haemophilus influenzae & Haemophilus influenzae type B (Hib) Disease
WHAT IS IT? Haemophilus influenzae are bacteria that naturally inhabit the human respiratory tract, sometimes causing disease when factors such as viral infections, chronic lung disease, extremes of age, or a compromised immune system contribute to illness. H influenzae type B (Hib) is a particular strain of H. influenzae, that is highly virulent and dangerous, particularly in young children. Hib disease is now rare, because of routine childhood vaccination to prevent it.
HOW DOES IT SPREAD? H. influenzae bacteria spread from person to person via airborne droplets or direct contact with oral secretions. Spread of bacteria may or may not cause symptoms of illness. Vaccination can reduce the spread of Hib bacteria and disease. Vaccination prevents Hib from colonizing the nasal passages, and reduces exposures to Hib in the population.
WHAT ILLNESSES DOES IT CAUSE? H. influenzae can cause many types of illness, most of which originate in the respiratory tract (ears, nose, throat, and chest). Infections may include local infections like otitis media, bronchitis, or pneumonia, or severe invasive disease like meningitis or blood-stream infection with sepsis. Severe, invasive infections were characteristic of Hib disease before the vaccine became available and included meningitis, mastoiditis, epiglottitis, and orbital /periorbital cellulitis.
HOW IS H. influenzae DISEASE TREATED? Antimicrobials are required to treat H. influenzae infections. Persons with severe illness are likely to be hospitalized and receive intravenous (IV) antibiotics.
HOW COMMON IS Hib DISEASE? Because of the introduction and routine use of the Hib conjugate vaccine, the current national rate is far less than 1 case per 100,000 children per year. Previously, Hib was the leading cause of bacterial meningitis in infants and children, with an annual incidence of 40 to 100 cases per 100,000 children in the U.S., and resulting in death or permanent disability for approximately 6,000 children per year.
HOW DOES GEORGIA TRACK DISEASES CAUSED BY H. influenzae? Invasive H. influenzae disease was made notifiable to public health in 1990. Active surveillance, through regular contact with laboratories was implemented statewide in 2001 to ensure complete case ascertainment. Isolates are requested for serotyping at the Georgia Public Health Laboratory. Epidemiologists complete case-report forms to characterize the type of infection and outcome.
HOW IS GEORGIA AFFECTED BY H. influenzae DISEASE? In 2008, 148 cases and 27 deaths were documented in Georgia from invasive H. influenzae disease, including 4 cases of Hib and no associated deaths. Figure 1 shows the number of cases in Georgia over the last 21 years and Figure 2 illustrates the incidence of invasive H. influenzae disease since 1987.
Georgia Department of Human Resources, Division of Public Health 2 Peachtree Street, NW Atlanta, GA 30303 (404) 657-2634 gaepinfo@dhr.state.ga.us http://health.state.ga.us

Number of Cases 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Figure 1: Reports of Invasive Haemophilus influenzae Disease Cases & Deaths, Georgia, 1987-2008

350 321

300

293 287

250

196

200

150

135

148

109

116 113 123 127

100 50

65 68 54 31 46 41 69 80 86

84 81

0

Year

Incidence per 100,000 Population
1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Figure 2: Incidence of Invasive Haemophilus influenzae Disease, Georgia, 1987-2008
6 5 4 3 2 1 0

Year

A

B

C

A Before 1992, most invasive Haemophilus influenzae disease was caused by H. influenzae serotype B (Hib). Incidence of Hib disease (and therefore all invasive H. influenzae disease) decreased rapidly from 1989 to 1992 as a result of the introduction of Hib conjugate vaccines.

B During 1993 to 2000, H. influenzae disease rates appear low, but case-ascertainment may have been incomplete in parts of the state under passive surveillance. C Since 2001, H. influenzae has been under active/audited surveillance statewide, resulting in more accurate disease rates.

SOURCE: State Electronic Notifiable Disease Surveillance System (SENDSS) **Calculation of 2008 incidence was performed using 2007 population estimates

Georgia Department of Human Resources, Division of Public Health 2 Peachtree Street, NW Atlanta, GA 30303 (404) 657-2634 gaepinfo@dhr.state.ga.us http://health.state.ga.us

Hib Disease in Georgia & Emerging Issues

Hib disease is now rare due to routine use of Hib conjugate vaccines, but continued surveillance for Hib disease is important to monitor the effectiveness of current vaccination efforts
Vaccination against Hib disease is part of the recommended childhood immunization schedule, beginning at age 2 months
A vaccine recall and resulting shortage since January 2008 has led to interim recommendations for vaccine use, still in effect in early 2009. CDC and ACIP recommend completion of the primary series (first 3 doses at 2, 4, and 6 months of age) for all children, while deferring the 4th (booster) dose unless a child is in a high risk category

Figure 3: Serotypes of Invasive H. influenzae Isolates, Georgia, 2008

Unknown 31%

A 1%
B 3%
E 3%
F 17%

Georgia documented 4 cases of Hib disease in 2008. One of these cases occurred in a child who was under-

Not Typable
45%

immunized (had not completed the

primary series against Hib). Of the

remaining 3 cases, two were older than

age 5 years (too old to qualify for vaccination), and the third had received the primary series

but had underlying health problems that may have contributed to susceptibility to infection.

As seen above in Figure 3, Hib disease constituted 3% of all invasive H. influenzae disease in Georgia in 2008. However, 31% of H. influenzae cases were not serotyped by the Georgia Public Health Laboratory, indicating the possibility of additional undetected Hib cases

In order to effectively monitor trends in Hib disease in a time of vaccine shortage, laboratorians and health care providers across the state are asked to promptly submit bacterial isolates from all cases to the Georgia Public Health Laboratory for serotyping

Figure 4 shows Hib disease cases in Georgia since 1998. An increased number of Hib cases during 2008, and a reduction in timely completion of the Hib vaccine primary series observed in the Georgia Registry of Immunization Transactions and Services (GRITS, not shown) suggest that greater efforts are needed to maintain low rates of Hib disease until the vaccine shortage resolves

Georgia Department of Human Resources, Division of Public Health 2 Peachtree Street, NW Atlanta, GA 30303 (404) 657-2634 gaepinfo@dhr.state.ga.us http://health.state.ga.us

Number of Cases

Figure 4: Hib Disease in Georgia by Age Group 1998-2008

4.5 4
3.5 3
2.5 2
1.5 1
0.5 0 1998

1999

2000

2001

2002

2003 Year

2004

2005

2006

2007

2008

< 2 Months 2 Months to 5 Years > 5 Years

Web-Based Resources for Haemophilus influenzae Disease Information
Georgia Division of Public Health: Acute Disease Epidemiology Section: Invasive Bacterial Disease: http://health.state.ga.us/epi/bacterial/
Centers for Disease Control & Prevention: Haemophilus influenzae Serotype B (Hib) Disease http://www.cdc.gov/ncidod/dbmd/diseaseinfo/haeminfluserob_t.htm
http://www.cdc.gov/meningitis/tech-clinical.htm
Georgia Immunization Program: http://health.state.ga.us/programs/immunization/

Date Updated: February 2009 Publication Number:
Georgia Department of Human Resources, Division of Public Health 2 Peachtree Street, NW Atlanta, GA 30303 (404) 657-2634 gaepinfo@dhr.state.ga.us http://health.state.ga.us