Hepatitis A epidemiology and demographics
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [2]; Associate Editor(s)-in-Chief: João André Alves Silva, M.D. [3]
Overview
Incidence
There were 1,398 reported cases of acute HAV in 2011, representing an estimated 2,700 (1,650- 4,370) actual acute cases.
Incidence declined sharply in states with historically consistently elevated rates included in the 1999 ACIP recommendations for routine vaccination of children. As a result, the majority of hepatitis A cases during recent years have been reported from states with historically low rates in which hepatitis A vaccination of children has not been widely implemented.[1]
In addition, the narrowing or elimination of national differences in age, race/ethnicity, and state-specific rates can be attributed largely to changes that occurred in the states in which routine hepatitis A vaccination of children was recommended and implemented. In 2004, for example, approximately two thirds of the nearly 6,000 cases were reported from states without childhood vaccination recommendations.[2]
The 2004 rate among all Hispanics in these states remained four times higher than among non-Hispanics and was seven times higher among Hispanic compared with non-Hispanic children. The highest rate in any demographic subgroup occurred among Hispanic children in states for which routine hepatitis A vaccination of children is not recommended.[3]
Age
In recent years, rates of hepatitis A have been similar among all age groups.[1]
Race
Historic differences in rates among racial/ethnic populations also have narrowed in the vaccine era. For example, recent rates among American Indians and Alaska Natives represent a 99% decline compared with the prevaccine era and are now approximately the same or lower than those of other racial/ethnic populations.[4] Rates among Hispanics also declined 87% during this period, from 20.6 cases per 100,000 population during 1990-1997 to 2.7 per 100,000 in 2004, but remain higher than those for non-Hispanics.[1][5]
Developed Countries
Elimination of historic geographic differences in incidence rates has also occurred, and since 2001, rates in states where vaccination was recommended have been approximately equal to the rest of the United States.[6] In recent years, counties with higher rates have varied from year to year and have been distributed throughout the country.[1]
Developing Countries
Areas with high levels of infection
In developing countries with very poor sanitary conditions and hygienic practices, most children (90%) have been infected with the hepatitis A virus before the age of 10. Those infected in childhood do not experience any noticeable symptoms.
Epidemics are uncommon because older children and adults are generally immune. Symptomatic disease rates in these areas are low and outbreaks are rare.[7]
Areas with intermediate levels of infection
In developing countries, countries with transitional economies and regions where sanitary conditions are variable, children often escape infection in early childhood. Ironically, these improved economic and sanitary conditions may lead to a higher susceptibility in older age groups and higher disease rates, as infections occur in adolescents and adults, and large outbreaks can occur.[7]
Areas with low levels of infection
In developed countries with good sanitary and hygienic conditions, infection rates are low.
Disease may occur among adolescents and adults in high-risk groups, such as injecting-drug users, men who have sex with men, people traveling to areas of high endemicity, and in isolated populations such as closed religious communities.[7]
References
- ↑ 1.0 1.1 1.2 1.3 Wasley A, Samandari T, Bell BP (2005). "Incidence of hepatitis A in the United States in the era of vaccination". JAMA : the Journal of the American Medical Association. 294 (2): 194–201. doi:10.1001/jama.294.2.194. PMID 16014593. Retrieved 2012-02-28. Unknown parameter
|month=ignored (help) - ↑ Wasley A, Finelli L, Bell B. Hepatitis A among U.S. children in era of vaccination. [Abstract no. 1025]. 43rd Annual Meeting of the Infectious Diseases Society of America, October 6-9, 2005, San Francisco, California. Alexandria, VA: Infectious Diseases Society of America; 2005.
- ↑ Wasley A, Finelli L, Bell B. Hepatitis A among U.S. children in era of vaccination. [Abstract no. 1025]. 43rd Annual Meeting of the Infectious Diseases Society of America, October 6-9, 2005, San Francisco, California. Alexandria, VA: Infectious Diseases Society of America; 2005.
- ↑ Bialek SR, Thoroughman DA, Hu D, Simard EP, Chattin J, Cheek J, Bell BP (2004). "Hepatitis A incidence and hepatitis a vaccination among American Indians and Alaska Natives, 1990-2001". American Journal of Public Health. 94 (6): 996–1001. PMC 1448379. PMID 15249305. Unknown parameter
|month=ignored (help);|access-date=requires|url=(help) - ↑ CDC. Hepatitis surveillance. Report no. 61. Atlanta, GA: US Department of Health and Human Services, CDC. 2006
- ↑ CDC. Hepatitis surveillance. Report no. 61. Atlanta, GA: US Department of Health and Human Services, CDC. 2006
- ↑ 7.0 7.1 7.2 Hepatitis A. World Health Organization. Fact sheet N 328, updated June 2014. Accessed 07/28/2014.[1]