Impact and effectiveness of monovalent rotavirus vaccine in Tajik children.

BACKGROUND: In 2015, Tajikistan became the second country in Central Asia to introduce rotavirus vaccine into its national immunization program. Before vaccine introduction, rotavirus was estimated to cause > 40% of pediatric diarrhea hospitalizations in Tajikistan. We aimed to assess the impact of rotavirus vaccine introduction on rotavirus disease burden and estimate rotavirus vaccine effectiveness (VE). METHODS: Using surveillance data from 2013 through 2019, we examined trends in monthly hospital admissions among children < 5 years old, before and after rotavirus vaccine introduction. Poisson regression was used to quantify decreases. VE was estimated using a test-negative case control design, with data from admissions during 2017 - 2019. Immunization records were obtained from clinics. RESULTS: Among enrolled children, rotavirus positivity declined from 42% to 25% in the post-vaccine introduction period, a decrease of 41% (95% Confidence Interval [CI]: 36 - 45%). Declines were greatest in children < 12 months of age. Estimated VE of a complete course of rotavirus vaccine was 55% (95% CI: 21 - 73%) among children 5 - 59 months of age and 64% (95% CI: 36 - 80%) among children 5 - 23 months of age. VE point estimates were higher among children receiving both doses of rotavirus vaccine non-concurrently with OPV and among children receiving their first dose of rotavirus vaccine at 4 - 11 months of age, but CIs were wide and overlapping. CONCLUSIONS: Our data demonstrate that rotavirus vaccine introduction was associated with a substantial reduction in pediatric rotavirus hospitalization burden in Tajikistan, and that rotavirus vaccination is effective in Tajik children.

A recombinase polymerase amplification assay for rapid detection of Crimean-Congo Haemorrhagic fever Virus infection.

BACKGROUND: Crimean-Congo Haemorrhagic fever Virus (CCHFV) is a rapidly emerging vector-borne pathogen and the cause of a virulent haemorrhagic fever affecting large parts of Europe, Africa, the Middle East and Asia. METHODOLOGY/PRINCIPLE FINDINGS: An isothermal recombinase polymerase amplification (RPA) assay was successfully developed for molecular detection of CCHFV. The assay showed rapid (under 10 minutes) detection of viral extracts/synthetic virus RNA of all 7 S-segment clades of CCHFV, with high target specificity. The assay was shown to tolerate the presence of inhibitors in crude preparations of mock field samples, indicating that this assay may be suitable for use in the field with minimal sample preparation. The CCHFV RPA was successfully used to screen and detect CCHFV positives from a panel of clinical samples from Tajikistan. CONCLUSIONS/SIGNIFICANCE: The assay is a rapid, isothermal, simple-to-perform molecular diagnostic, which can be performed on a light, portable real-time detection device. It is ideally placed therefore for use as a field-diagnostic or in-low resource laboratories, for monitoring of CCHF outbreaks at the point-of-need, such as in remote rural regions in affected countries.

Identification and analysis of Crimean-Congo hemorrhagic fever virus from human sera in Tajikistan.

BACKGROUND: Crimean-Congo hemorrhagic fever (CCHF) is a virulent tick-borne disease reported in more than 30 countries across Europe, Africa, and Asia. The disease is considered endemic in several Central Asian countries, including Tajikistan; however reports of human cases from these regions rarely reach the West. METHODS: We analyzed all historical confirmed cases of CCHF in Tajikistan, mapping these reports against geographic data to assess risk areas. In addition, comprehensive analysis was undertaken on the 2010 human CCHF cohort to demonstrate effective methodologies for diagnosing this disease in-country. RESULTS: These data show that CCHF is endemic in Tajikistan, and several large clusters have been recorded. Endemic foci of disease are localized to the southern region, with geographical factors such as altitude, monthly mean temperature, and monthly mean precipitation levels limiting establishment of tick vectors in other areas. Genomic analysis of viral RNA from a 2010 human case revealed high nucleotide homology (99%) to a strain isolated in Tajikistan in 1990. CONCLUSIONS: CCHF is an important vector-borne and nosocomial pathogen in Tajikistan. The ability to rapidly detect cases using real-time RT-PCR shortly after admission in the hospital setting allows prompt implementation of barrier nursing techniques, therefore reducing onward transmission of the virus.

Crimean-Congo hemorrhagic fever in Tajikistan.

Crimean-Congo hemorrhagic fever (CCHF) is a pathogenic tick-borne disease caused by a single-stranded negative-sense RNA virus classified within the Nairovirus genus of the family Bunyaviridae. Cases of CCHF have been registered in Tajikistan since the disease was first brought to medical attention in 1944. However, historical Tajik manuscripts describe the features of hemorrhagic fever associated with ticks, indicating that the disease might have been known in this region for many years before it was officially characterized. Here we review the historical context of CCHF in Tajikistan, much of which has been described over several decades in the Russian literature, and include reports of recent outbreaks in Tajikistan.