Use of the enzyme-linked immunosorbent assay (ELISA) for the estimation of serum antibodies in an influenza virus vaccine study.

The value of the enzyme-linked immunosorbent assay (ELISA) for determining the serum antibody responses of volunteers following immunisation with various inactivated influenza virus vaccines was assessed, and the incidence of seroconversions, as measured by both haemagglutination-inhibition (HI) and ELISA response of the volunteers determined. ELISA was found to be more sensitive than the HI test in detecting serum antibodies, but was also less specific under the conditions used. With regard to efficacy, the whole virus vaccine proved to be more effective in inducing serum antibody in an unprimed population than either tween-ether split or subunit adsorbed vaccines, but the reverse situation held when the population was primed with respect to the antigen concerned.