Do we really need ribavirin in the treatment of crimean-congo hemorrhagic Fever?

Vaccine approaches and treatment aspects against Crimean Congo hemorrhagic fever

Crimean-Congo hemorrhagic fever [CCHF] is a severe infectious viral disease caused by a tick borne virus which can lead to fatal hemorrhagic disease in humans. It has been reported from some continents including Africa, Asia and Europe. Virus is transmitted to human mainly through tick bite, whose acquire infection from reservoirs wild and domesticated mammalians and ostriches. Currently no approved vaccine or drug is available for CCHF and prevention is mainly based on biosecurity measures. Ribavirin is the only approved drug that has been used in some countries to treat human disease, however some new studies did not prove the Ribavirin efficacy. Different strategies to design effective vaccines, have been conducted through years, from inactivated virus to nucleotide-based ones including DNA and mRNA vaccines. In this study we review of pioneering vaccine candidate platforms.

Favipiravir and Ribavirin protect immunocompetent mice from lethal CCHFV infection

Crimean-Congo hemorrhagic fever virus (CCHFV) causes Crimean-Congo hemorrhagic fever (CCHF) in humans with high morbidity and mortality. Currently, there is neither an approved antiviral drug nor a vaccine against CCHFV. In this study, we describe a lethal model of CCHFV infection using a mouse-adapted strain of CCHFV (MA-CCHFV) in adult wild-type male mice. Infected mice developed high viral loads, tissue pathology, and inflammatory immune responses before ultimately succumbing to the infection. We used the model to evaluate the protective efficacy of nucleoside analogs monulpiravir, favipiravir, ribavirin, the antibiotic tigecycline and the corticosteroids dexamethasone and methylprednisolone against lethal CCHFV infection. Tigecycline, monulpiravir and the corticosteroids failed to protect mice from lethal MA-CCHFV infection. In contrast, favipiravir and ribavirin protected animals from clinical disease and death even when treatment was delayed. Despite demonstrating uniform protection, CCHFV RNA persisted in survivors treated with favipiravir and ribavirin. Nevertheless, the study demonstrated the anti-CCHFV efficacy of favipiravir and ribavirin in a model with intact innate immunity and establishes this model for continued development of CCHFV countermeasures.

Identification of the crucial parameters regarding the efficacy of ribavirin therapy in Crimean-Congo haemorrhagic fever (CCHF) patients: a systematic review and meta-analysis

OBJECTIVES

Recently, ribavirin has been suggested as a therapeutic approach in Crimean-Congo haemorrhagic fever (CCHF) patients; however, there are controversial findings about its efficacy. In the current study, a meta-analysis was systematically performed to assess the effectiveness of ribavirin administration regarding CCHF patient survival and to explore the most important influential parameters for its efficacy.

METHODS

All of the outcomes of the clinically studied CCHF patients who were treated with ribavirin were included in the meta-analysis.

RESULTS

Overall, 24 studies met our criteria. Although the studies did not have high quality there was no heterogeneity and publication bias across studies. The results indicated that the administration of ribavirin to CCHF patients significantly decreased the mortality rate (by 1.7-fold) compared with those who did not receive this medication. Furthermore, it was found that the prescription of ribavirin in the initial phase of disease was more effective, and a delay in the start of treatment resulted in a 1.6-fold increase in mortality rate. In addition, interventional therapy resulted in an ∼2.3-fold reduction in the mortality rate of those who received ribavirin along with corticosteroids compared with those who were treated with ribavirin monotherapy.

CONCLUSIONS

This meta-analysis reveals that ribavirin should be considered as a crucial antiviral drug in the therapeutic approach used for CCHF patients, especially in early phases of the disease. Additionally, it seems that the administration of corticosteroids alongside ribavirin can play an effective role in alleviation of the disease status, particularly in haemorrhagic phases.

Crimean-Congo hemorrhagic fever: An update

Crimean-Congo hemorrhagic fever (CCHF) is a severe form of hemorrhagic fever caused by a virus of the genus Nairovirus. The amplifying hosts are various mammal species that remain asymptomatic. Humans are infected by tick bites or contact with animal blood. CCHF has a broad geographic distribution and is endemic in Africa, Asia (in particular the Middle East) and South East Europe. This area has expanded in recent years with two indigenous cases reported in Spain in 2016 and 2018. The incubation period is short with the onset of symptoms in generally less than a week. The initial symptoms are common to other infectious syndromes with fever, headache, myalgia and gastrointestinal symptoms. The hemorrhagic syndrome occurs during a second phase with sometimes major bleeding in and from the mucous membranes and the skin. Strict barrier precautionary measures are required to prevent secondary and nosocomial spread. CCHF may be documented by PCR detection of the virus genome during the first days after the onset of illness, and then by serological testing for IgM antibodies as from the 2nd week after infection. Patient management is mainly based on supportive care. Despite a few encouraging retrospective reports, there is no confirmed evidence that supports the use of ribavirin for curative treatment. Nevertheless, the World Health Organization continues to recommend the use of ribavirin to treat CCHF, considering the limited medical risk related to short-term treatment. The prescription of ribavirin should however be encouraged post-exposure for medical professionals, to prevent secondary infection.

Ribavirin for treating Crimean Congo haemorrhagic fever

BACKGROUND

Crimean Congo haemorrhagic fever (CCHF) is a tick-borne disease that occurs in parts of Asia, Europe and Africa. Since 2000 the infection has caused epidemics in Turkey, Iran, Russia, Uganda and Pakistan. Good-quality general supportive medical care helps reduce mortality. There is uncertainty and controversy about treating CCHF with the antiviral drug ribavirin.

OBJECTIVES

To assess the effects of ribavirin for treating people with Crimean Congo haemorrhagic fever.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register; the Central Register of Controlled Trials (CENTRAL); MEDLINE (PubMed); Embase (OVID); Science Citation Index-Expanded, Social Sciences Citation index, conference proceedings (Web of Science); and CINAHL (EBSCOHost). We also searched the WHO International Clinical Trials Registry Platform (ICTRP) and ClinicalTrials.gov for trials in progress. We conducted all searches up to 16 October 2017. We also contacted experts in the field and obtained further studies from these sources.

SELECTION CRITERIA

We evaluated studies assessing the use of ribavirin in people with suspected or confirmed Crimean Congo haemorrhagic fever. We included randomised control trials (RCTs); non-randomised studies (NRSs) that included more than 10 participants designed as cohort studies with comparators; and case-control studies.

DATA COLLECTION AND ANALYSIS

Two review authors assessed eligibility, risk of bias, and extracted data. For non-randomized studies we used the ROBINS-I tool to assess risk of bias. The main effects analysis included all studies where we judged the risk of bias to be low, moderate or high. We summarized dichotomous outcomes using risk ratios (RRs) and continuous outcomes using mean differences (MDs), and used meta-analyses where appropriate. We carried out a subsidiary appraisal and analysis of studies with critical risk of bias for the primary outcome, as these are often cited to support using ribavirin.

MAIN RESULTS

For the main effects analysis, five studies met our inclusion criteria: one RCT with 136 participants and four non-randomized studies with 612 participants. We excluded 18 non-randomized studies with critical risk of bias, where none had attempted to control for confounding.We do not know if ribavirin reduces mortality (1 RCT; RR 1.13, 95% confidence interval (CI) 0.29 to 4.32; 136 participants; very low-certainty evidence; 3 non-randomized studies; RR 0.72, 95% CI 0.41 to 1.28; 549 participants; very low-certainty evidence). We do not know if ribavirin reduces the length of stay in hospital (1 RCT: mean difference (MD) 0.70 days, 95% CI -0.39 to 1.79; 136 participants; and 1 non-randomized study: MD -0.80, 95% CI -2.70 to 1.10; 50 participants; very low-certainty evidence). We do not know if it reduces the risk of patients needing platelet transfusions (1 RCT: RR 1.23, 95% CI 0.77 to 1.96; 136 participants; very low-certainty evidence). For adverse effects (including haemolytic anaemia and a need to discontinue treatment), we do not know whether there is an increased risk with ribavirin in people with CCHF as data are insufficient.We do not know if adding ribavirin to early supportive care improves outcomes. One non-randomized study assessed mortality in people receiving ribavirin and supportive care within four days or less from symptom onset compared to after four days since symptom onset: mortality was lower in the group receiving early supportive care and ribavirin, but it is not possible to distinguish between the effects of ribavirin and early supportive medical care alone.In the subsidiary analysis, 18 studies compared people receiving ribavirin with those not receiving ribavirin. All had a critical risk of bias due to confounding, reflected in the mortality point estimates favouring ribavirin.

AUTHORS' CONCLUSIONS

We do not know if ribavirin is effective for treating Crimean Congo haemorrhagic fever. Non-randomized studies are often cited as evidence of an effect, but the risk of bias in these studies is high.

Crimean-Congo hemorrhagic fever in Turkey: Current status and future challenges

Crimean-Congo hemorrhagic fever (CCHF) is a tick-borne viral disease of humans that affects a wide geographic area of Africa and Eurasia, including Turkey, Iran, Pakistan, Afghanistan and Russia. Since the first detection of CCHF cases in Turkey in 2002, more than 9700 patients have been reported, with an overall mortality rate just under 5%. This article assesses the present epidemiological situation of CCHF in Turkey, with an updated literature review, describes national practices and summarizes lessons learned in preparation for future outbreaks.

Crimean-Congo hemorrhagic fever with hyperbilirubinemia and ascites: An unusual presentation

Crimean-Congo hemorrhagic fever (CCHF) is a fatal systemic viral infection which is an important health problem in Turkey. Many systemic symptoms have been reported including fever, hemorrhage, headache, fatigue, muscle ache, abdominal pain, nausea and vomiting. A 45-year-old male farmer with CCHF presented with massive peritoneal effusion and hyperbilirubinemia. To our knowledge, this is the first case of peritoneal effusion and hyperbilirubinemia in an adult patient with CCHF. His clinical symptoms successfully improved with supportive therapy. In patients who live in endemic areas with atypical presentation for the diagnosis of CCHF should be kept in mind.