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A study published in NEJM provides evidence that Zika virus RNA remain longer in blood and semen than in other body fluids, which suggests these may be superior diagnostic specimens.
This is the first study in which researchers examined multiple body fluids for the presence of Zika virus over a length of time.
The team sought to determine the frequency and duration of detectable Zika virus RNA in serum, saliva, urine, semen, and vaginal secretions.
They collected such specimens from 150 men and women in Puerto Rico who initially tested positive for Zika virus in urine or blood. The specimens were collected weekly for the first month and then at 2 months, 4 months, and 6 months.
The researchers tested all specimens using the Trioplex RT-PCR assay, a test that can be used to detect dengue, chikungunya, and Zika virus RNA. There have been allegations that this assay is less effective than a test used to detect Zika virus alone.
The researchers also performed validation analyses for the use of the Trioplex RT-PCR assay in semen. And they tested serum using the Zika IgM Antibody Capture Enzyme-Linked Immunosorbent Assay (Zika MAC-ELISA).
The US Centers for Disease Control and Prevention (CDC) developed both Zika MAC-ELISA and the Trioplex RT-PCR assay. This research was supported by the CDC.
After sample testing was complete, the researchers used parametric Weibull regression models to estimate the time to the loss of Zika virus RNA, which they reported in medians and 95th percentiles.
Results
The researchers said 88% of subjects (132/150) had detectable Zika virus RNA in at least 1 serum specimen. The median time to the loss of RNA detection in serum was 14 days (95% confidence interval [CI], 11 to 17), and the 95th percentile of time was 54 days (95% CI, 43 to 64).
The team also found that 61.7% of eligible subjects (92/149) had detectable Zika virus RNA in at least 1 urine specimen. The median time to the loss of RNA detection in urine was 8 days (95% CI, 6 to 10), and the 95th percentile of time was 39 days (95% CI, 31 to 47).
Fifteen subjects (10.1%) had detectable Zika virus RNA in urine but not serum, and 55 (36.7%) had RNA in serum but not urine.
Fifty-six percent of eligible male subjects (31/55) had Zika virus RNA in at least 1 semen specimen. The median time to loss of RNA detection in semen was 34 days (95% CI, 28 to 41), and the 95th percentile of time was 81 days (95% CI, 64 to 98).
The researchers noted that 11 of the 55 subjects had Zika virus RNA in their semen at their last visit and were still being followed at the time the NEJM article was written. The maximum duration of RNA detection was 125 days after the onset of symptoms.
Zika virus RNA levels were detectable in few saliva samples, with 10.2% of eligible subjects (15/147) having detectable levels in at least 1 saliva specimen.
Only 1 of 50 women (2%) had detectable Zika virus RNA in vaginal secretions.
“The findings of this study are important for both diagnostic and prevention purposes,” said study author Eli Rosenberg, PhD, of Emory University in Atlanta, Georgia.
“The results fully support current CDC sexual transmission recommendations but also provide critical information to help in understanding how often and how long evidence of Zika virus can be found in different body fluids. This knowledge is key to improving accuracy and effectiveness of testing methods while providing important baseline information for future research.” 
A study published in NEJM provides evidence that Zika virus RNA remain longer in blood and semen than in other body fluids, which suggests these may be superior diagnostic specimens.
This is the first study in which researchers examined multiple body fluids for the presence of Zika virus over a length of time.
The team sought to determine the frequency and duration of detectable Zika virus RNA in serum, saliva, urine, semen, and vaginal secretions.
They collected such specimens from 150 men and women in Puerto Rico who initially tested positive for Zika virus in urine or blood. The specimens were collected weekly for the first month and then at 2 months, 4 months, and 6 months.
The researchers tested all specimens using the Trioplex RT-PCR assay, a test that can be used to detect dengue, chikungunya, and Zika virus RNA. There have been allegations that this assay is less effective than a test used to detect Zika virus alone.
The researchers also performed validation analyses for the use of the Trioplex RT-PCR assay in semen. And they tested serum using the Zika IgM Antibody Capture Enzyme-Linked Immunosorbent Assay (Zika MAC-ELISA).
The US Centers for Disease Control and Prevention (CDC) developed both Zika MAC-ELISA and the Trioplex RT-PCR assay. This research was supported by the CDC.
After sample testing was complete, the researchers used parametric Weibull regression models to estimate the time to the loss of Zika virus RNA, which they reported in medians and 95th percentiles.
Results
The researchers said 88% of subjects (132/150) had detectable Zika virus RNA in at least 1 serum specimen. The median time to the loss of RNA detection in serum was 14 days (95% confidence interval [CI], 11 to 17), and the 95th percentile of time was 54 days (95% CI, 43 to 64).
The team also found that 61.7% of eligible subjects (92/149) had detectable Zika virus RNA in at least 1 urine specimen. The median time to the loss of RNA detection in urine was 8 days (95% CI, 6 to 10), and the 95th percentile of time was 39 days (95% CI, 31 to 47).
Fifteen subjects (10.1%) had detectable Zika virus RNA in urine but not serum, and 55 (36.7%) had RNA in serum but not urine.
Fifty-six percent of eligible male subjects (31/55) had Zika virus RNA in at least 1 semen specimen. The median time to loss of RNA detection in semen was 34 days (95% CI, 28 to 41), and the 95th percentile of time was 81 days (95% CI, 64 to 98).
The researchers noted that 11 of the 55 subjects had Zika virus RNA in their semen at their last visit and were still being followed at the time the NEJM article was written. The maximum duration of RNA detection was 125 days after the onset of symptoms.
Zika virus RNA levels were detectable in few saliva samples, with 10.2% of eligible subjects (15/147) having detectable levels in at least 1 saliva specimen.
Only 1 of 50 women (2%) had detectable Zika virus RNA in vaginal secretions.
“The findings of this study are important for both diagnostic and prevention purposes,” said study author Eli Rosenberg, PhD, of Emory University in Atlanta, Georgia.
“The results fully support current CDC sexual transmission recommendations but also provide critical information to help in understanding how often and how long evidence of Zika virus can be found in different body fluids. This knowledge is key to improving accuracy and effectiveness of testing methods while providing important baseline information for future research.”
A study published in NEJM provides evidence that Zika virus RNA remain longer in blood and semen than in other body fluids, which suggests these may be superior diagnostic specimens.
This is the first study in which researchers examined multiple body fluids for the presence of Zika virus over a length of time.
The team sought to determine the frequency and duration of detectable Zika virus RNA in serum, saliva, urine, semen, and vaginal secretions.
They collected such specimens from 150 men and women in Puerto Rico who initially tested positive for Zika virus in urine or blood. The specimens were collected weekly for the first month and then at 2 months, 4 months, and 6 months.
The researchers tested all specimens using the Trioplex RT-PCR assay, a test that can be used to detect dengue, chikungunya, and Zika virus RNA. There have been allegations that this assay is less effective than a test used to detect Zika virus alone.
The researchers also performed validation analyses for the use of the Trioplex RT-PCR assay in semen. And they tested serum using the Zika IgM Antibody Capture Enzyme-Linked Immunosorbent Assay (Zika MAC-ELISA).
The US Centers for Disease Control and Prevention (CDC) developed both Zika MAC-ELISA and the Trioplex RT-PCR assay. This research was supported by the CDC.
After sample testing was complete, the researchers used parametric Weibull regression models to estimate the time to the loss of Zika virus RNA, which they reported in medians and 95th percentiles.
Results
The researchers said 88% of subjects (132/150) had detectable Zika virus RNA in at least 1 serum specimen. The median time to the loss of RNA detection in serum was 14 days (95% confidence interval [CI], 11 to 17), and the 95th percentile of time was 54 days (95% CI, 43 to 64).
The team also found that 61.7% of eligible subjects (92/149) had detectable Zika virus RNA in at least 1 urine specimen. The median time to the loss of RNA detection in urine was 8 days (95% CI, 6 to 10), and the 95th percentile of time was 39 days (95% CI, 31 to 47).
Fifteen subjects (10.1%) had detectable Zika virus RNA in urine but not serum, and 55 (36.7%) had RNA in serum but not urine.
Fifty-six percent of eligible male subjects (31/55) had Zika virus RNA in at least 1 semen specimen. The median time to loss of RNA detection in semen was 34 days (95% CI, 28 to 41), and the 95th percentile of time was 81 days (95% CI, 64 to 98).
The researchers noted that 11 of the 55 subjects had Zika virus RNA in their semen at their last visit and were still being followed at the time the NEJM article was written. The maximum duration of RNA detection was 125 days after the onset of symptoms.
Zika virus RNA levels were detectable in few saliva samples, with 10.2% of eligible subjects (15/147) having detectable levels in at least 1 saliva specimen.
Only 1 of 50 women (2%) had detectable Zika virus RNA in vaginal secretions.
“The findings of this study are important for both diagnostic and prevention purposes,” said study author Eli Rosenberg, PhD, of Emory University in Atlanta, Georgia.
“The results fully support current CDC sexual transmission recommendations but also provide critical information to help in understanding how often and how long evidence of Zika virus can be found in different body fluids. This knowledge is key to improving accuracy and effectiveness of testing methods while providing important baseline information for future research.”