In the year old age group, seroprevalence rates have also decreased compared with previous reports. This suggests that the epidemiology is shifting from high to intermediate endemicity, with the population susceptible to HAV infection shifting from children to adolescents and adults. Even in Mexico, where anti-HAV prevalence remained high, it was shown that the average age at infection among children hospitalized with hepatitis increased from 6 years in to 10 years in Furthermore, data from Brazil, Argentina, Venezuela and Mexico shows that HAV seroprevalence is significantly lower in people living in medium and high socioeconomic conditions[ 6 , 7 , 26 ].
In the same six countries, a seroepidemiological study was undertaken in to determine whether this pattern has changed. In all of the countries except Brazil and Venezuela, the seroprevalence of anti-HAV was significantly higher in females than in males. Seroprevalence rates in American Indian and Amazonian populations tend to be higher, except for some extremely isolated villages.
The results show that there has been a shift from high to medium endemicity of HAV infection in a large part of Latin America, which may result in more clinical cases in adolescents and adults and a greater potential for outbreaks[ 25 , 28 ]. In Bolivia, studies performed in the same rural area in and ten years later showed a significant decrease in the seroprevalence rates from In Argentina, a sharp reduction in the infection rate was reached by the introduction of a universal HAV vaccination program in and other countries, like Brazil and Chile, are evaluating the possibility of introducing a specific prevention policy[ 29 - 31 ].
Adequate supplies of safe drinking water and proper disposal of sewage within communities, combined with personal hygiene practices, such as regular hand washing, reduce the spread of HAV[ 32 ]. There was a marked reduction in virus transmission in most developed countries several decades ago due to improvements in living standards, better sanitation and environmental conditions. The same trend was observed during the s in several developing countries with increasing economic prosperity.
These changes occurred without a specific vaccination strategy, underscoring the critical importance of environmental and personal hygiene and sanitation to prevent fecal-oral transmission of pathogens[ 17 ]. Safe and effective inactivated hepatitis A vaccines have been available since worldwide and are generally used in developed countries to protect risk groups and stop outbreaks. The different vaccines are similar in terms of efficacy and side-effects, highly immunogenic, inducing antibodies to HAV that persist for at least 15 years.
Based on current scientific evidence, protection is considered to be life long after a complete hepatitis A vaccination schedule two doses. Long-term protection after a single dose needs to be further surveyed. The vaccines can be delivered alone or in combination and administered with flexible schedules[ 33 , 34 ]. Vaccination policies range from being part of national universal immunization programs for children to targeting at risk groups.
Countries or regions that have implemented universal immunization, e. Israel, Italy Puglia , Spain Catalonia and the United States, have demonstrated a successful impact on the incidence of hepatitis A; the data for the United States is particularly striking, with evidence of a two-thirds decrease in admissions to hospital and markedly lower medical expenditures between and Targeted policies, especially for travelers, have also been shown to be effective and are adopted by different countries and vaccination is included as post-exposure prophylaxis of contacts[ 35 ].
In some rapidly developing countries, a new approach to control and prevention of HAV epidemics using a vaccine is being considered. In South America, several trials to evaluate the immunogenicity and safety of inactivated HAV vaccine were performed among Argentinean and Chilean children[ 36 , 37 ], while cost-benefit studies were performed in Brazil, where a hypothetical vaccination strategy was developed to eliminate hepatitis A[ 28 ].
In in Argentina, a universal hepatitis vaccination with a single dose at 12 mo of age was implemented. Argentina's Ministry of Health was established to monitor the impact and follow up the strategy in order to evaluate the need for a second dose.
Surveillance data showed an important decline in hepatitis A incidence rates in , when the rate recorded was the lowest in the last 12 years. It is important to consider that these declines since have been unprecedented in magnitude and have been observed in all age groups and regions, showing a marked herd immunity effect.
Brazil and Chile reassessed their immunization policy after cost-effectiveness studies and looking at the successful results of the areas where vaccines were introduced[ 29 ]. In China, at the same time when lifestyles began changing and the country's economy boomed, hepatitis A vaccines were introduced. The vaccine meets the requirements of China and WHO for the manufacture of biological substances and is now widely applied in the immunization program to prevent HAV epidemics in China and other countries, such as India[ 38 ].
Recent Indian studies with this vaccine have confirmed its high immunogenicity and excellent safety profile[ 39 , 40 ]. Recommendations for the use of the hepatitis A vaccine vary considerably among countries.
Guidance from WHO on hepatitis A vaccines emphasizes the need to consider the cost-benefit and sustainability of various prevention strategies in the context of the epidemiological characteristics of the setting where vaccination is being considered. In more developed countries, hepatitis A vaccine is primarily being used to protect persons at increased risk, such as travelers to areas where hepatitis A is endemic, men who have sex with men, or persons with chronic liver disease.
Hepatitis A vaccination currently has few indications in the areas of the world where the infection is highly endemic and where most of the population is already immune. In areas of intermediate or high endemicity that are transitioning to a lower level of transmission, shifts in the age-specific patterns of the disease result in an increasing proportion of susceptible adolescents and adults, often in urban areas or higher socioeconomic classes, among whom outbreaks may occur[ 3 , 32 - 40 , 41 ].
In these settings, HAV vaccination may be considered on the basis on epidemiological and cost-effectiveness studies. Hepatitis A virus is still a major cause of infection and disease in the world and heterogeneous pockets of susceptible and exposed individuals may co-exist in rapidly developing societies. Thereafter, small localized or large outbreaks of HAV infection will remain a threat in such areas.
The situation demands that conclusive guidelines be produced for HAV vaccination in these communities after characterizing them appropriately. WHO is in the process of revising its position paper on hepatitis A, issued in , with a view to: update and evaluate the data on disease burden, epidemiology, vaccine products and availability and immunization protection; review the use of the vaccine in outbreaks and for contacts of cases; and issue guidance to countries where the prevalence rates are declining from high levels.
In determining national policies, the results of appropriate epidemiological and cost-benefit studies need to be carefully considered and the public health impact weighed[ 18 , 32 ]. National Center for Biotechnology Information , U. Journal List World J Hepatol v.
World J Hepatol. Published online Mar Author information Article notes Copyright and License information Disclaimer. Author contributions: Franco E designed the research; Meleleo C, Serino L, Sorbara D and Zaratti L performed the literature search and evaluation; all authors contributed to writing the paper. All rights reserved. This article has been cited by other articles in PMC. Abstract Hepatitis A is the most common form of acute viral hepatitis in the world.
Asia HAV seroprevalence rates vary considerably among countries in Asia, with some continuing to have high rates and others making a transition to moderate or low incidence. Central and South America Latin American countries show many of the characteristics of developing countries, with migration from rural communities to cities leading to urban areas of low income and social deprivation.
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J Infect Dis. Epidemiology of hepatitis A in Finland in J Med Virol. Risk groups for hepatitis A virus infection. Tufenkeji H. Hepatitis A shifting epidemiology in the Middle East and Africa. Johnston L. Hepatitis A and B-A brief overview. SA Pharmaceutical Journal. Seroprevalence of hepatitis A virus antibodies among a sample of Egyptian children. East Mediterr Health J. Age-specific seroprevalence of hepatitis a among school children in central Tunisia.
Am J Trop Med Hyg. Seroepidemiology of hepatitis A virus in Kuwait. World J Gastroenterol. Changing prevalence of anti-hepatitis A virus in adolescents in a rural township in Taiwan. Chang Gung Med J. Increasing incidence of hepatitis A in Korean adults.
Laboratory characteristics of recent hepatitis A in Korea: ongoing epidemiological shift. Barzaga BN. Hepatitis A outbreaks in China during application of molecular epidemiology. Hepatol Int. Decline in the risk of hepatitis A virus infection in China, a country with booming economy and changing lifestyles. J Viral Hepat. Mathur P, Arora NK. Epidemiological transition of hepatitis A in India: issues for vaccination in developing countries.
Indian J Med Res. Outbreaks of hepatitis A among children in western India. Tanaka J. Hepatitis A shifting epidemiology in Latin America. Hepatitis A in Latin America: a changing epidemiologic pattern. Gentile A. The need for an evidence-based decision-making process with regard to control of hepatitis A.
Braz J Infect Dis. Vacchino MN. Incidence of Hepatitis A in Argentina after vaccination. Changing epidemiology of hepatitis A in Brazil: reassessing immunization policy. Valenzuela MT. Acute viral hepatitis. Goldman-Cecil Medicine. Philadelphia, PA: Elsevier Saunders; chap Hepatitis A. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. Advisory Committee on Immunization Practices Recommended immunization schedule for children and adolescents aged 18 years or younger - United States, Updated by: Michael M.
Editorial team. Preventing hepatitis A. To reduce your risk of spreading or catching the hepatitis A virus: Always wash your hands thoroughly after using the restroom and when you come in contact with an infected person's blood, stools, or other bodily fluid.
Avoid unclean food and water. Avoid unclean food and water You should take the following precautions: Avoid raw shellfish. Beware of sliced fruit that may have been washed in contaminated water. Travelers should peel all fresh fruits and vegetables themselves. Do not buy food from street vendors. Use only carbonated bottled water for brushing teeth and drinking in areas where the water may be unsafe. Remember that ice cubes can carry infection.
If no water is available, boiling water is the best method for eliminating hepatitis A. Bringing the water to a full boil for at least 1 minute generally makes it safe to drink. Heated food should be hot to the touch and eaten right away. If you are Exposed. Common reasons why you may need to receive this shot include: You live with someone who has hepatitis A. You recently had sexual contact with someone who has hepatitis A.
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