All 31 cases provided acute sera, 19 provided convalescent sera and 14 had viral throat/nose swabs taken.
Sera from individuals known to be affected by immunosuppressive conditions or by an acute infection or to have recently undergone blood transfusion were excluded.
Dilutions of the sera were allowed to react with the coating antigen.
Sera were tested at 1 in 200 dilution on antigen coated plates.
A week after the last dose of antigen, jirds were bled from the retro-orbital plexus and immune sera were isolated.
The rabbits were bled before the immunizations, and the sera obtained were used for control studies.
The sources of sera used have been described previously [8].
The wells were incubated for 2 h at room temperature with diluted human sera.
