Ribavirin has ‘demonstrable’ effect on Crimean-Congo hemorrhagic fever
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In 2016, a man walking through a field in Spain was bitten by a tick carrying the virus that causes Crimean-Congo hemorrhagic fever, or CCHF. The man died of the disease, and a nurse who treated him also was infected. It was the first time local transmission of CCHF was documented in Spain, expanding the geographic range of the often fatal infection and giving researchers more evidence of the shifting ranges of some ticks.
It gave them something else, too: an opportunity to study the effect of treating CCHF with ribavirin, an antiviral drug that has shown activity against many positive and negative stranded RNA viruses in vitro and in vivo but has remained a controversial treatment for CCHF because of a lack of evidence that it works in humans, according to researchers in a new study published in The Journal of Infectious Diseases.
WHO estimates that the mortality rate of CCHF outbreaks is as high as 40%, and the CDC says the infection has killed between 9% and 50% of hospitalized patients in documented outbreaks. Hyalomma ticks are the main vector for CCHF, which is endemic in Africa, parts of Asia and the Middle East but had never been documented in Europe outside of some countries in the eastern and southeastern parts of the continent until the two infections in Spain.
The index patient in Spain was a man aged 62 years who was bitten on the knee by a tick as he walked through a field in central-western Spain. He died just over a week later. According to an initial report published last year in The New England Journal of Medicine, a nurse who treated him was likely infected through contact with the man’s blood as she helped intubate him and insert femoral venous and arterial catheters as he bled profusely shortly before dying.
In the new study, Gustavo Palacios, PhD, director of the Center for Genomic Sciences in the United States Army Medical Research Institute of Infectious Diseases, and colleagues said the nurse, a woman aged 50 years, was treated orally and then intravenously with ribavirin beginning 5 days into the course of infection. She received 1,000 mg ribavirin orally every 6 hours for 24 hours and intravenously for the next 24 hours, followed by 500 mg IV ribavirin every 8 hours for 4 days, in addition to supportive care.
Plasma samples taken before, during and after the treatment were sequenced and analyzed. According to Palacios and colleagues, they showed that ribavirin had a “demonstrable effect” on the nurse’s CCHF infection, including a “dramatic” decline in viral load.
“Obviously, a single-case study limits significantly our ability to generalize these results. However, [CCHF virus] is an emerging infection of global health importance and the paucity of clinical data on the efficacy of ribavirin as a viable treatment for CCHF makes these observations valuable,” they wrote.
“The results support the continued evaluation of ribavirin as an antiviral for use in [CCHF virus]-infected patients and emphasize the need for a randomized control trial that includes the study of viral populations before, during and after treatment to conclusively determine if ribavirin’s antiviral effect influences treatment outcomes and the appropriate dosing regimen required for therapeutic use.” – by Gerard Gallagher
For more information:
Negredo A, et al. N Engl J Med. 2017;doi:10.1056/NEJMsa1612890.
Disclosures: The authors report no relevant financial disclosures.