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
The incidence of hepatitis A in the United States in 2011 was 0.4 cases per 100,000 population. In recent years, rates of hepatitis A have been similar among all age groups. After the introduction of the HAV vaccine, historic differences in rates among racial/ethnic populations have also narrowed. In developed countries, elimination of historic geographic differences in incidence rates has also occurred. 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.
Incidence
- There were 1,398 reported cases of acute HAV in 2011, representing an estimated 2,700 (1,650- 4,370) actual acute cases.[1]
- The number of acute hepatitis A cases reported in the United States declined by approximately 53%, from 2,979 in 2007 to 1,398 in 2011.[1]
- Of the 50 states that reported hepatitis A cases in 2011, 24 states had rates below the national rate.[1]
- The rate of acute hepatitis A in the United States declined from 1.0 case per 100,000 population in 2007 to 0.4 cases per 100,000 population in 2011.[1]
- In 2011, the case rate ranged from no cases in New Hampshire and North Dakota to 1.2 cases per 100,000 population in Arizona.[1]
Age
In recent years, rates of hepatitis A have been similar among all age groups.[2]
Race
Historic differences in the rates of hepatitis A among racial/ethnic populations also have been 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.[3] 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.[2][4]
Developed Countries
There has been an elimination of historic geographic differences in incidence rates of hepatitis A in the United States. Since 2001, rates of hepatitis A in states where vaccination was recommended have been approximately equal to the rest of the United States.[5] In recent years, counties with higher rates have varied from year to year and have been distributed throughout the country.[2]
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.[6]
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.[6]
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.[6]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 "Hepatitis A Epidemics".
- ↑ 2.0 2.1 2.2 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) - ↑ 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
- ↑ 6.0 6.1 6.2 Hepatitis A. World Health Organization. Fact sheet N 328, updated June 2014. Accessed 07/28/2014.[1]