Zika RNA Lasts Longer Than Expected in Blood — Physician’s First Watch

Medical News |
February 15, 2017

Zika RNA Lasts Longer Than Expected in Blood

By Kelly Young

Edited by David G. Fairchild, MD, MPH, and Lorenzo Di Francesco, MD, FACP, FHM

The Zika virus appears to persist in serum longer than expected, according to a cohort study published in the New England Journal of Medicine and presented at the Conference on Retroviruses and Opportunistic Infections.

Roughly 150 people in Puerto Rico with laboratory-confirmed Zika infection regularly provided samples of serum, urine, saliva, semen, and vaginal secretions until all their samples tested negative for Zika RNA.

Here are medians and 95th percentiles for time between symptom onset and samples testing negative:

  • Serum: median, 14 days; 95th percentile, 54 days

  • Urine: 8 and 39 days

  • Semen: 34 and 81 days

Notably, 4% of men continued to have detectable levels of RNA in semen 125 days after symptom onset. The virus wasn't frequently detected in saliva or vaginal secretions.

The authors say their findings could help inform efforts to diagnose and prevent transmission of Zika.

Reader Comments (1)

Rose Webster Other Healthcare Professional, Ophthalmology, Writer

Our public health authorities (WHO and CDC) apparently ignored a Eurosurveillance Rapid Communication: "Detection of Zika Virus RNA in Whole Blood of Imported Zika Virus Disease Cases Up to 2 Months After Symptom Onset, Israel, December 2015 to April 2016." Source: Eurosurveillance, Volume 21, Issue 26, 30 June 2016

More recently (Dec. 2016): "detection of Zika virus RNA in vaginal secretions up to day 14 and in erythrocytes up to day 81" (almost 3 months in blood). Source: December 14, 2016 CDC post called Prolonged Detection of Zika Virus in Vaginal Secretions and Whole Blood.

Re: "ZIKV viremia is normally detectable only within the first week ..." is what is commonly written in medical literature.

I wonder if this is because of the highly flawed Trioplex assay (which fails to detect 40 percent of Zika cases and all four strains of dengue). The ZIKV Detect IgM Capture ELISA test, made by InBios International has been deemed "too inaccurate" by the FDA, as well.

As of November 12th, 2016, a whopping 564,571 donations have tested positive on the cobas Zika test.
Dr. Jay S. Epstein, Office of Blood Research and Review director at the FDA, said in a statement:

"Zika virus is a transfusion transmitted disease which can cause potentially severe consequences including microcephaly and Guillain-Barré syndrome. The requirement to test blood donations for Zika virus has already resulted in interdicting contaminated collections confirming the value of testing."

Sadly, in my numerous attempts to let both Canadian Blood Services and the American Red Cross know that they should extend their deferment policies of 21 days and 28 days, respectively, they informed me they would not. India imposed a 120-day wait (the only country I know of to heed the early warnings).

Source (with citations): http://www.infobarrel.com/Zika_Virus_Our_Tainted_Blood_Supply

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