It has been observed that despite the availability of the vaccine for hepatitis A in the market it may not be necessary to be given to children by the time they are 5 years old.why?
It has been observed that despite the availability of the vaccine for hepatitis A in the market it may not be necessary to be given to children by the time they are 5 years old.why?
Hepatitis A virus (HAV) is present worldwide and is the agent of one of the most widespread infections transmitted via the fecal-oral route. In countries with poor hygiene and consequent wide presence of feces in the environment, the vast majority of subjects is infected within 5 years of age (usually without any sign or symptom of acute hepatitis), thus acquiring life-long immunity. Outbreaks and epidemics are rare due to the high herd immunity level in the population.
When socio-economic and hygienic conditions improve, the decrease of HAV circulation progressively leads to a decline of herd immunity.
Hepatitis A virus (HAV) is present worldwide and is the agent of one of the most widespread infections transmitted via the fecal-oral route. In countries with poor hygiene and consequent wide presence of feces in the environment, the vast majority of subjects is infected within 5 years of age (usually without any sign or symptom of acute hepatitis), thus acquiring life-long immunity. Outbreaks and epidemics are rare due to the high herd immunity level in the population.
When socio-economic and hygienic conditions improve, the decrease of HAV circulation progressively leads to a decline of herd immunity.
