Skip to comments.Rapid-Test Sensitivity for Novel Swine-Origin Influenza A (H1N1) Virus in Humans
Posted on 10/13/2009 7:24:33 PM PDT by neverdem
To the Editor: The Naval Health Research Center serves as the Navy hub for the Department of Defense's Global Emerging Infections Surveillance and Response System (GEIS), in which it monitors influenza-like illness among recruit trainees of all military services, military dependents, and crew members of large Navy ships (population, >1000). The center works in collaboration with the Border Infectious Disease Surveillance Project of the Centers for Disease Control and Prevention (CDC), which monitors populations located on the border between California and Mexico. The first two human cases of novel swine-origin influenza A (H1N1) virus (S-OIV), known as swine flu, in the United States were detected through these programs.1 In the first case, an untypeable influenza A strain was identified at a surveillance site of the Naval Health Research Center by a new diagnostic device. The test results were forwarded per protocol to the study reference laboratory for polymerase-chain-reaction (PCR) confirmation and were subsequently forwarded to the CDC for identification by sequencing. In the second case, a sample that was obtained at a border surveillance site was found to contain an untypeable influenza A strain on PCR testing at the center. Further characterization by PCR assay and electrospray ionization mass spectrometry indicated a swine-origin virus, and sequence data that were sent to the CDC revealed that the viruses in the two samples were identical. In response, surveillance activities of all programs were enhanced to include increased sampling rates, more clinical sites, decreased turnaround time in the laboratory, and rapid influenza testing with the use of QuickVue Influenza A+B (Quidel).
From April 20 through May 30, 2009, the center processed 3066 specimens with the use of a real-time reverse-transcriptase PCR (RT-PCR) assay,2 which revealed 273 confirmed cases of S-OIV (8.9%), 18 cases of H1N1 seasonal influenza (0.6%), and 31 cases of H3N2...
(Excerpt) Read more at content.nejm.org ...
diagnostic sensitivity: the conditional probability that a person having a disease will be correctly identified by a clinical test, determined by taking the number of true positive results and dividing it by the total cases of the disease (which is the sum of the numbers of true positive plus false negative results).
diagnostic specificity: the probability that a person not having a disease will be correctly identified by a clinical test, i.e., the number of true negative results divided by the total number of all those without the disease (which is the sum of the number of true negative plus false positive results).
The characteristics, the sheer existence of this disease, mandate a significant tendency towards mutation. Any one who needs a flu shot every year, this mutating (if it’s natural) bug would require the same every few months. Oh Noes!
Yesterday on Fox I heard Dr. Isadore Rosenfeld say if you have the flu, there’s a 95 percent chance it’s H1N1 because that’s the main flu that’s infecting people right now.
‘I can’t get smallpox, I’ve had the cowpox.’
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.