Evidence of Hepatitis A Virus Person-to-Person Transmission in Household Outbreaks

Abstract

The person-to-person transmission of the hepatitis A virus primarily occurs in enclosed spaces, particularly in the presence of inadequate hygiene conditions and a high proportion of susceptible individuals. Thus, intimate family contact stands out as a risk factor for HAV infection dissemination. The present study aimed to evaluate the occurrence of household HAV transmission. Blood samples were collected from patients with hepatitis A (index cases) and their family members (contacts) that were referred to an ambulatory care clinic specializing in viral hepatitis. A total of 97 samples were collected from 30 families with a confirmed hepatitis A case (index case). Serological and molecular techniques for the diagnosis of hepatitis A were conducted on all samples. HAV infection (anti-HAV IgM + and/or HAV RNA +) was detected in 34.3% (23/67) of the contacts; 34.3% (23/67) of the contacts were immune to HAV, and 31.4% (21/67) were susceptible. In the household contacts, HAV immunity was significantly associated with older age; susceptibility to infection and HAV infection were associated with younger age. Household outbreaks were detected in 16/30 families studied. Co-circulation of subgenotypes IA and IB was found in the household outbreaks, and person-to-person transmission was evidenced in six of the household outbreaks, with 100% homology between the index case and contact strains. The results demonstrated the relevance of HAV household transmission, reaffirming the need for hepatitis A vaccine administration in susceptible contacts and effective infection control procedures to prevent the extension of household outbreaks.

A single dose of inactivated hepatitis A vaccine promotes HAV-specific memory cellular response similar to that induced by a natural infection

“…Of these individuals, 9 (45%) were female. Acute hepatitis A cases were defined as follows: (1) by the use of a commercially available enzyme-linked immunosorbent assay (ELISA) kit for anti-HAV IgM (Abbott, USA); (2) by the observation of clinical features of acute-onset hepatitis within 2-8 weeks in a previously healthy individual; and (3) by the observation of aminotransferase levels that were at least 10-fold higher than the upper limit of normal [21][22][23][24]. Patients exhibiting co-infection with other forms of viral hepatitis were not included.…”

Impact of the mandatory Hepatitis A immunization program: before and after the vaccine in Ankara, Central of Turkey

“…5 So, an effective vaccination program in this group will also prevent transmission, thus providing effective protection in other age groups including un-immunized individuals. 6,7…”

“…4,5 The infection is transmitted mainly by the fecal-oral route through contact with infected cases, unhealthy drinking water and food. 6 Following the incubation period of 2-6 weeks, HAV infection can manifest in cholestatic, non-cholestatic, subfulminant or fulminant forms. 1,4 Endemicity of HAV infection and the prevalence of anti-HAV antibodies are highly related with the economic status and sanitary conditions of the regions or countries.…”

Changes in cellular proliferation and plasma products are associated with liver failure

“…There are a large number of outbreaks of hepatitis A in Brazil; HAV infection is the major etiology of AH and ALF[17,31,32]. Here, we introduced plasma mtDNA level as a new predictor for HAV-induced ALF syndrome.…”