tetano
Editor, Senior Moderator
Open Forum Infect Dis. 2015 Nov 3;2(4)
fv166. doi: 10.1093/ofid/ofv166. eCollection 2015.
[h=1]A Downward Trend of the Ratio of Influenza RNA Copy Number to Infectious Viral Titer in Hospitalized Influenza A-Infected Patients.[/h] Van Wesenbeeck L[SUP]1[/SUP], D'Haese D[SUP]1[/SUP], Tolboom J[SUP]2[/SUP], Meeuws H[SUP]1[/SUP], Dwyer DE[SUP]3[/SUP], Holmes M[SUP]4[/SUP], Ison MG[SUP]5[/SUP], Katz K[SUP]6[/SUP], McGeer A[SUP]7[/SUP], Sadoff J[SUP]2[/SUP], Weverling GJ[SUP]2[/SUP], Stuyver L[SUP]1[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] Background. Efficacy endpoints in influenza clinical trials may include clinical symptoms and virological measurements, although virology cannot serve as the primary endpoint. We investigated the relationship between influenza A RNA copy number and quantity of infectious viruses in hospitalized influenza patients. Methods. One hundred fifty influenza-infected, hospitalized patients were included in this prospective cohort study spanning the 2012-2013 influenza season. Daily nasopharyngeal samples were collected during hospitalization, and influenza A RNA copy number and infectious viral titer were monitored. Results. The decay rate for 50% tissue culture infectious dose (TCID50) was 0.51 ? 0.14 log10 TCID50/mL per day, whereas the RNA copy number decreased at a rate of 0.41 ? 0.04 log10 copies/mL per day (n = 433). The log ratio of the RNA copy number to the infectious viral titer within patient changes significantly with -0.25 ? 0.09 units per day (P = .0069). For a 12-day observation period, the decay corresponds to a decline of this ratio of 3 log influenza RNA copies. Conclusions. Influenza RNA copy number in nasal swabs is co-linear with culture, although the rate of decay of cell culture-based viral titers was faster than that observed with molecular methods. The study documented a clear decreasing log ratio of the RNA copy number to the infectious viral titer of the patients over time.
[h=4]KEYWORDS:[/h] infectious viral titer; influenza A TCID50; influenza A viral load; influenza RNA copy number; nasopharyngeal swabs
PMID: 26677457 [PubMed]
fv166. doi: 10.1093/ofid/ofv166. eCollection 2015.[h=1]A Downward Trend of the Ratio of Influenza RNA Copy Number to Infectious Viral Titer in Hospitalized Influenza A-Infected Patients.[/h] Van Wesenbeeck L[SUP]1[/SUP], D'Haese D[SUP]1[/SUP], Tolboom J[SUP]2[/SUP], Meeuws H[SUP]1[/SUP], Dwyer DE[SUP]3[/SUP], Holmes M[SUP]4[/SUP], Ison MG[SUP]5[/SUP], Katz K[SUP]6[/SUP], McGeer A[SUP]7[/SUP], Sadoff J[SUP]2[/SUP], Weverling GJ[SUP]2[/SUP], Stuyver L[SUP]1[/SUP].
[h=3]Author information[/h]
[h=3]Abstract[/h] Background. Efficacy endpoints in influenza clinical trials may include clinical symptoms and virological measurements, although virology cannot serve as the primary endpoint. We investigated the relationship between influenza A RNA copy number and quantity of infectious viruses in hospitalized influenza patients. Methods. One hundred fifty influenza-infected, hospitalized patients were included in this prospective cohort study spanning the 2012-2013 influenza season. Daily nasopharyngeal samples were collected during hospitalization, and influenza A RNA copy number and infectious viral titer were monitored. Results. The decay rate for 50% tissue culture infectious dose (TCID50) was 0.51 ? 0.14 log10 TCID50/mL per day, whereas the RNA copy number decreased at a rate of 0.41 ? 0.04 log10 copies/mL per day (n = 433). The log ratio of the RNA copy number to the infectious viral titer within patient changes significantly with -0.25 ? 0.09 units per day (P = .0069). For a 12-day observation period, the decay corresponds to a decline of this ratio of 3 log influenza RNA copies. Conclusions. Influenza RNA copy number in nasal swabs is co-linear with culture, although the rate of decay of cell culture-based viral titers was faster than that observed with molecular methods. The study documented a clear decreasing log ratio of the RNA copy number to the infectious viral titer of the patients over time.
[h=4]KEYWORDS:[/h] infectious viral titer; influenza A TCID50; influenza A viral load; influenza RNA copy number; nasopharyngeal swabs
PMID: 26677457 [PubMed]