The MRC's evidence in 1928 for the efficacy of the serum is doubtful and, by 1936, convalescent serum
had been characterized as harmless, and ineffectual.
samples were available for roughly half of all culture-negative cases, and among those, nearly 90% lacked immunologic reactivity to Y pestis.
SARS case definition to allow exclusion of cases with a negative convalescent serum
Of the 66 probable SARS cases, convalescent serum
has been collected for 40 (61%).
However, the collection and testing of convalescent serum
is an ongoing priority to precisely characterize the epidemiology of SARS in the United States and worldwide.
Negative findings (i.e., the absence of antibody to SARS-CoV in convalescent serum
obtained >21 days after symptom onset) have been documented for 54 cases (41 suspect and 13 probable).
Obtaining convalescent serum
samples to make a final determination about infection with SARS-CoV is critical.
As of April 23, of the 245 reported SARS cases, 45(18%) have diagnostic SARS-CoV laboratory findings (i.e., positive findings based on detection of antibody to SARS-CoV in serum or evidence of virus in respiratory specimens by reverse transcriptase polymerase chain reaction analysis, or negative findings based on absence of antibody to SARS-CoV in convalescent serum
obtained >21 days after symptom onset).
One patient also has had a negative convalescent serum
All suspect WNV illnesses should be screened by testing CSF and appropriately timed acute and convalescent serum
specimens for IgM ELISA antibody.
Acute and convalescent serum
specimens were available from six patients (including five of the seven patients for whom PCR was performed and one patient for whom PCR testing was not performed); these paired serum specimens were tested at CDC for antibodies by the Remel test.
Confirmatory testing by plaque reduction neutralization for IgG antibody from convalescent serum