Serologic testing for antibody to SARS-associated coronavirus (SARS-CoV)
has been performed for 32 (48%) probable cases and was positive for seven,
six of which have been described previously as laboratory-confirmed cases.
For one patient, a reverse transcriptase polymerase chain reaction (RT-PCR)
assay detected SARS-CoV ribonucleic acid in a sputum specimen collected 14
days after illness onset4,5;
this patient subsequently had antibody to SARS-CoV. The seventh patient, a
household contact of one of the six patients with positive serology, was reported
previously as a probable SARS patient on the basis of clinical and epidemiologic
criteria.4 Among the seven patients, four
had positive serology on or before day 12 after onset of symptoms. The other
three had negative serologic tests on day 4, 6, and 14, respectively, and
a positive test in the next available serum sample on day 28, 25, and 41,
respectively. Serologic testing has been performed for 111 (37%) suspect cases;
antibody was not detected for any of those tested.