Could oral fluid be used to evaluate anti-hepatitis A virus status in individuals living in difficult-to-access areas?

A strategy adopted by different countries to reduce the number of new cases of hepatitis A is the vaccination. However, the mosaic of the epidemiological profile in developing countries has hampered the establishment of a unified nationwide vaccination program. To determinate national vaccination policies, the results of epidemiological studies need to be carefully considered. For this monitoring, the use of oral fluid is very important due to the painless and non invasive collection characteristics. There are few studies investigating which oral fluid collection device is optimal to detect low antibody levels and its use in selecting individuals for vaccination. So, the present study aimed to evaluate different oral fluid collection devices to detect humoral immune response against hepatitis A virus and its application in epidemiological studies. Therefore, 90 matched serum and oral fluid samples were collected from volunteers with different immune status, under ideal conditions of collection (optimization panel); and 224 matched samples in difficult-to-access areas (epidemiological study). Serum was collected by venipuncture and the oral fluid was obtained using three commercial devices: Salivette(®), OraSure(®) and ChemBio(®). Serum and oral fluid were submitted to a commercial immunoblot to detect total anti-HAV antibodies. The optimization panel demonstrated that ChemBio(®) device had the best performance (100% agreement), followed by OraSure(®) (95.4%) and Salivette(®) (90.8%). The optimal collection device (ChemBio(®)), tested in a difficult-to-access area and evaluated under precarious conditions of collection, showed similar prevalence of total anti-HAV between serum and oral fluid, 80.8% and 79%, respectively. A follow-up was performed to evaluate the stability of oral fluid and it was observed that 210 days after the collection it was possible to detect anti-HAV antibodies. Oral fluid can be used to detect low levels of specific-antibody, being important to select age groups to be vaccinated. Therewith, the choice of proper collection device is essential to evaluate HAV antibodies in the epidemiological scenario.