Tick-borne encephalitis virus (TBEV) plays an important role in infectious human morbidity, particularly in Russia and the Middle Urals. The Siberian subtype of TBEV (S-TBEV) is dominant in the Middle Urals. Determining the origin of S-TBEV strains in this territory and also in the European part of Russia and the Baltic countries is very important for understanding the cause of its distribution. The surface glycoprotein E gene was partially sequenced in 165 S-TBEV isolates collected in the Middle Urals between 1966 and 2008. Nucleotide and amino acid sequence identity of the studied isolates is 94 and 97.4 %, respectively. Eighty per cent of them are represented by six clusters with identical amino acid sequences in the glycoprotein E fragment analysed. We have determined four types of isolate distribution in the explored territory: local, split, corridor and diffuse. The average rate of nucleotide substitutions per site year "1 is estimated to be 1.56¾10 "4 . The age of the S-TBEV population was evaluated to be slightly less than 400 years. Phylogenetic analysis of the data and comparison with historical events indicate that the distribution of S-TBEV strains in the Middle Urals and the European part of Russia originated twice from different foci in western Siberia. This is related to the first land road into Siberia and the Trans-Siberian Way, which functioned at different times. The main reason for such rapid distribution of S-TBEV strains is the anthropogenic factor, i.e. human economic activity during the colonization of new territories in Siberia in the recent past.

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The control arm of the phase III VIVIANE (Human PapillomaVIrus: Vaccine Immunogenicity ANd Efficacy; NCT00294047) study in women >25 years was studied to assess risk of progression from cervical HPV infection to detectable cervical intraepithelial neoplasia (CIN). The risk of detecting CIN associated with the same HPV type as the reference infection was analysed using Kaplan–Meier and multivariable Cox models. Infections were categorised depending upon persistence as 6‐month persistent infection (6MPI) or infection of any duration. The 4‐year interim analysis included 2,838 women, of whom 1,073 (37.8%) experienced 2,615 infections of any duration and 708 (24.9%) experienced 1,130 6MPIs. Infection with oncogenic HPV types significantly increased the risk of detecting CIN grade 2 or greater (CIN2+) versus non‐oncogenic types. For 6MPI, the highest risk was associated with HPV‐33 (hazard ratio [HR]: 31.9 [8.3–122.2, p < 0.0001]). The next highest risk was with HPV‐16 (21.1 [6.3–70.0], p < 0.0001). Similar findings were seen for infections of any duration. Significant risk was also observed for HPV‐18, HPV‐31, and HPV‐45. Concomitant HPV infection or CIN grade 1 or greater associated with a different oncogenic HPV type increased risk. Most women (79.3%) with an HPV infection at baseline cleared detectable infections of any duration, and 69.9% cleared a 6MPI. The risk of progression of HPV infection to CIN2+ in women >25 years in this study was similar to that in women 15–25 years in PATRICIA.

Tick-borne encephalitis (TBE) remains one of the major public health concerns in northern Eurasia, and its' area is expanding. TBE virus (TBEV) includes three subtypes and several monophyletic groups, cocirculating in Russia. Five inactivated vaccines are used for TBE prophylaxis. The rising number of people subjected to vaccination brings up the issue of the impact of individual recipient characteristics on vaccination efficacy. The present work studies correlations among the vaccination scheme, sex, age, body mass index (BMI), chronic diseases, postvaccinal reaction, pre-existing anti-TBEV antibodies, and postvaccinal humoral immunity development. Sera were collected during clinical trials in the TBEV Siberian subtype endemic area. Adult recipients were vaccinated with Tick-E-Vac and EnceVir vaccines based on Far-Eastern TBEV strains. Vaccine ability to induce humoral immunity in different categories of recipients was estimated by seroconversion rates and the percentage of recipients with high neutralizing antibody titers (≥1:500). High immunogenicity of vaccines based on Far-Eastern TBEV strains in the TBEV Siberian subtype endemic area in all groups of recipients was demonstrated. Impact of pre-existing contact with the virus and high BMI on humoral immune response development 14 days after the first immunization was evidenced. Nevertheless, the difference was significantly less pronounced 30 days after the first vaccination and undetectable after the second one.

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