Detection of hepatitis A antibodies by ELISA using saliva as clinical samples

RESUMO

The possibility of detecting acute infection and immunity using body fluids that are easier to collect than blood, mainly in children, would facilitate the investigation and follow-up of outbreaks of hepatitis A (HAV). Our study was carried out to evaluate the detection of anti-HAV IgM, IgA and total antibodies in saliva using serum samples as reference. Forty three paired serum and saliva samples were analyzed. From this total, 24 samples were obtained from children and 1 from one adult during the course of acute hepatitis A; an additional 18 samples were obtained from health professionals from Adolfo Lutz Institute. The sensitivity to detect anti-HAV IgM was 100 per cent (95 per cent CI 79.1 to 100.0 per cent), employing saliva as clinical samples. In detecting anti-HAV IgA, the sensitivity was 80.8 per cent (95 per cent CI 60.0 to 92.7 per cent) and for the total antibodies was 82.1 per cent (95 per cent CI 62.4 to 93.2 per cent). The specificity was 100 per cent for each. The rate of agreement was high comparing the results of serum and saliva samples for detecting HAV antibodies. We conclude that saliva is an acceptable alternative specimen for diagnosing acute hepatitis A infection, and for screening individuals to receive hepatitis A vaccine or immunoglobulin.