The most effective measure for the control of hepatitis A virus (HAV)
infection is to prevent fecal contamination of the hands, food and water. One
preventive measure is the administration of immunoglobulin (IG) within 2 weeks after
HAV exposure, which leads to effective protection in 85% of infected individuals.
Currently, there are two main types of hepatitis A vaccine: live attenuated virus and
inactivated virus vaccines. Live attenuated virus vaccines are weakly immunogenic
when administered orally or parenterally, only one injection is administered, and they
are licensed in China and Russia. Inactivated vaccines employ purified, formalininactivated,
whole viruses that are produced in cell culture, are highly immunogenic
and protect against both infection and disease. Inactivated vaccines can be monovalent
or combination (HAV-HBV vaccine or HAV-typhoid vaccine). Monovalent
vaccination regimens include two doses at an interval of 6 to 18 months between
injections, with the first administered at 12 months of age. Nearly 100% of
immunocompetent patients present immunity one month after receiving the
recommended two doses, and adequate antibody levels could persist for 25 years or
longer in adults and for 14 years or longer in children. The CDC recommends HAV
vaccination according to the prevalence and incidence of hepatitis A. Some countries
have introduced the HAV vaccine in childhood immunization calendars, leading to a
decrease in the incidence of HAV. In Brazil, a single dose of HAV vaccine is
recommended for children at 12-23 months of age by the health care system
immunization program.
Keywords: Applicability, Combination vaccines, Control, Efficacy, Hepatitis A
virus, Inactivated vaccines, Live attenuated virus vaccines, Monovalent vaccines,
Prevention.
