Oral fluid testing facilitates understanding of hepatitis A virus household transmission.

Becky Haywood,Richard S Tedder,Nick Andrews,Siew Lin Ngui,Koye Balogun,Kazim Beebeejaun,Sema Mandal

doi:10.1017/s095026881900027x

Becky Haywood, Richard S Tedder + Show 5 more

Open Access

https://doi.org/10.1017/s095026881900027x

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Abstract

The public health response to sporadic hepatitis A virus (HAV) infection, hepatitis A, can be complex especially when the index case is a child and no obvious source is identified. Identifying an infection source may avoid mass immunisation within schools when transmission is found to have occurred within the household. Screening of asymptomatic contacts via venepuncture can be challenging and unacceptable, as a result non-invasive methods may facilitate public health intervention. Enzyme-linked immunoassays were developed to detect HAV immunoglobulin M (IgM) and immunoglobulin G (IgG) in oral fluid (ORF). A validation panel of ORF samples from 30 confirmed acute HAV infections were all reactive for HAV IgM and IgG when tested. A panel of 40 ORF samples from persons known to have been uninfected were all unreactive. Two hundred and eighty household contacts of 72 index cases were screened by ORF to identify HAV transmission within the family and factors associated with household transmission. Almost half of households (35/72) revealed evidence of recent infection, which was significantly associated with the presence of children ⩽11 years of age (odds ratio 9.84, 95% confidence interval: 2.74-35.37). These HAV IgM and IgG immunoassays are easy to perform, rapid and sensitive and have been integrated into national guidance on the management of hepatitis A cases.

Highlights

Hepatitis A virus (HAV) is a picornavirus causing faecal-orally transmitted acute liver disease, hepatitis A
All 40 non-reactive oral fluid (ORF) samples were found to be unreactive for HAV immunoglobulin M (IgM) and immunoglobulin G (IgG) giving a specificity for IgG and IgM of 100%
To assess the reproducibility of the assays 40 samples were re-tested by another operator with different component lot numbers giving a concordance of 100% for the IgM assay and 97.5% for the IgG assay

Summary

Introduction

Hepatitis A virus (HAV) is a picornavirus causing faecal-orally transmitted acute liver disease, hepatitis A. Public Health England (PHE) recommends selective immunisation for to those who are at increased risk of infection including travellers to endemic areas, those at occupational risk, persons who inject drugs and men who have sex with men [2]. Susceptibility to HAV infection varies in the population; it is highest in those under 30 years of age, with >80% of such individuals being seronegative for antibody to HAV [3]. Seroprevalence increases with age and by the age of 60 more than three quarters of the population are seropositive from previous infection or immunisation [3]. There is potential for localised outbreaks in England and Wales, especially if primary schools are involved as young children are frequently implicated in spread due to variable levels of personal hygiene and high levels of susceptibility [4]

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