Circulation of pertussis and poor protection against diphtheria among middle-aged adults in 18 European countries

Reported incidence of pertussis in the European Union (EU) and the European Economic Area (EEA) varies and may not reflect the real situation, while vaccine-induced protection against diphtheria and tetanus seems sufficient. We aimed to determine the seroprevalence of DTP antibodies in EU/EEA countries within the age groups of 40-49 and 50-59 years. Eighteen countries collected around 500 samples between 2015 and 2018 (N = 10,302) which were analysed for IgG-DTP specific antibodies. The proportion of sera with pertussis toxin antibody levels ≥100 IU/mL, indicative of recent exposure to pertussis was comparable for 13/18 countries, ranging between 2.7-5.8%. For diphtheria the proportion of sera lacking the protective level (<0.1 IU/mL) varied between 22.8-82.0%. For tetanus the protection was sufficient. Here, we report that the seroprevalence of pertussis in these age groups indicates circulation of B. pertussis across EU/EEA while the lack of vaccine-induced seroprotection against diphtheria is of concern and deserves further attention.

Transmission of HIV Drug Resistance and the Predicted Effect on Current First-line Regimens in Europe

Transmitted human immunodeficiency virus drug resistance in Europe is stable at around 8%. The impact of baseline mutation patterns on susceptibility to antiretroviral drugs should be addressed using clinical guidelines. The impact on baseline susceptibility is largest for nonnucleoside reverse transcriptase inhibitors.

Background. Numerous studies have shown that baseline drug resistance patterns may influence the outcome of antiretroviral therapy. Therefore, guidelines recommend drug resistance testing to guide the choice of initial regimen. In addition to optimizing individual patient management, these baseline resistance data enable transmitted drug resistance (TDR) to be surveyed for public health purposes. The SPREAD program systematically collects data to gain insight into TDR occurring in Europe since 2001.

Methods. Demographic, clinical, and virological data from 4140 antiretroviral-naive human immunodeficiency virus (HIV)–infected individuals from 26 countries who were newly diagnosed between 2008 and 2010 were analyzed. Evidence of TDR was defined using the WHO list for surveillance of drug resistance mutations. Prevalence of TDR was assessed over time by comparing the results to SPREAD data from 2002 to 2007. Baseline susceptibility to antiretroviral drugs was predicted using the Stanford HIVdb program version 7.0.

Results. The overall prevalence of TDR did not change significantly over time and was 8.3% (95% confidence interval, 7.2%–9.5%) in 2008–2010. The most frequent indicators of TDR were nucleoside reverse transcriptase inhibitor (NRTI) mutations (4.5%), followed by nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations (2.9%) and protease inhibitor mutations (2.0%). Baseline mutations were most predictive of reduced susceptibility to initial NNRTI-based regimens: 4.5% and 6.5% of patient isolates were predicted to have resistance to regimens containing efavirenz or rilpivirine, respectively, independent of current NRTI backbones.

Conclusions. Although TDR was highest for NRTIs, the impact of baseline drug resistance patterns on susceptibility was largest for NNRTIs. The prevalence of TDR assessed by epidemiological surveys does not clearly indicate to what degree susceptibility to different drug classes is affected.

Patterns of transmitted HIV drug resistance in Europe vary by risk group

Background

In Europe, a continuous programme (SPREAD) has been in place for ten years to study transmission of drug resistant HIV. We analysed time trends of transmitted drug resistance mutations (TDRM) in relation to the risk behaviour reported.

Methods

HIV-1 patients newly diagnosed in 27 countries from 2002 through 2007 were included. Inclusion was representative for risk group and geographical distribution in the participating countries in Europe. Trends over time were calculated by logistic regression.

Results

From the 4317 patients included, the majority was men-having-sex-with-men -MSM (2084, 48%), followed by heterosexuals (1501, 35%) and injection drug users (IDU) (355, 8%). MSM were more often from Western Europe origin, infected with subtype B virus, and recently infected (<1 year) (p<0.001). The prevalence of TDRM was highest in MSM (prevalence of 11.1%), followed by heterosexuals (6.6%) and IDU (5.1%, p<0.001). TDRM was predominantly ascribed to nucleoside reverse transcriptase inhibitors (NRTI) with a prevalence of 6.6% in MSM, 3.3% in heterosexuals and 2.0% in IDU (p = 0.001). A significant increase in resistance to non- nucleoside reverse transcriptase inhibitors (NNRTIs) and a decrease in resistance to protease inhibitors was observed in MSM (p = 0.008 and p = 0.006, respectively), but not in heterosexual patients (p = 0.68 and p = 0.14, respectively).

Conclusions

MSM showed to have significantly higher TDRM prevalence compared to heterosexuals and IDU. The increasing NNRTI resistance in MSM is likely to negatively influence the therapy response of first-line therapy, as most include NNRTI drugs.

Limited cross-border infections in patients newly diagnosed with HIV in Europe

BACKGROUND

International travel plays a role in the spread of HIV-1 across Europe. It is, however, not known whether international travel is more important for spread of the epidemic as compared to endogenous infections within single countries. In this study, phylogenetic associations among HIV of newly diagnosed patients were determined across Europe.

RESULTS

Data came from the SPREAD programme which collects samples of newly diagnosed patients that are representative for national HIV epidemics. 4260 pol sequences from 25 European countries and Israel collected in 2002-2007 were included.We identified 457 clusters including 1330 persons (31.2% of all patients). The cluster size ranged between 2 and 28. A number of 987 patients (74.2%) were part of a cluster that consisted only of patients originating from the same country. In addition, 135 patients (10.2%) were in a cluster including only individuals from neighboring countries. Finally, 208 patients (15.6%) clustered with individuals from countries without a common border. Clustering with patients from the same country was less prevalent in patients being infected with B subtype (P-value <0.0001), in men who have sex with men (P-value <0.0001), and in recently infected patients (P-value =0.045).

CONCLUSIONS

Our findings indicate that the transmission of HIV-1 in Europe is predominantly occurring between patients from the same country. This could have implications for HIV-1 transmission prevention programmes. Because infections through travelling between countries is not frequently observed it is important to have good surveillance of the national HIV-1 epidemics.

HIV-1 subtype distribution and its demographic determinants in newly diagnosed patients in Europe suggest highly compartmentalized epidemics

Background

Understanding HIV-1 subtype distribution and epidemiology can assist preventive measures and clinical decisions. Sequence variation may affect antiviral drug resistance development, disease progression, evolutionary rates and transmission routes.

Results

We investigated the subtype distribution of HIV-1 in Europe and Israel in a representative sample of patients diagnosed between 2002 and 2005 and related it to the demographic data available. 2793 PRO-RT sequences were subtyped either with the REGA Subtyping tool or by a manual procedure that included phylogenetic tree and recombination analysis. The most prevalent subtypes/CRFs in our dataset were subtype B (66.1%), followed by sub-subtype A1 (6.9%), subtype C (6.8%) and CRF02_AG (4.7%). Substantial differences in the proportion of new diagnoses with distinct subtypes were found between European countries: the lowest proportion of subtype B was found in Israel (27.9%) and Portugal (39.2%), while the highest was observed in Poland (96.2%) and Slovenia (93.6%). Other subtypes were significantly more diagnosed in immigrant populations. Subtype B was significantly more diagnosed in men than in women and in MSM > IDUs > heterosexuals. Furthermore, the subtype distribution according to continent of origin of the patients suggests they acquired their infection there or in Europe from compatriots.

Conclusions

The association of subtype with demographic parameters suggests highly compartmentalized epidemics, determined by social and behavioural characteristics of the patients.

Phylogenetic analysis of the Latvian HIV-1 epidemic

The Latvian HIV-1 outbreak among intravenous drug users (IDUs) in 1997-1998 involved subtype A1. To obtain a more complete picture of the Latvian HIV-1 epidemic, 315 HIV-1-infected patients diagnosed in 1990-2005 representing different transmission groups and geographic regions were phylogenetically characterized using env V3 and gag p17 sequences. Subtypes A1 and B infections were found in 76% and 22% of the patients, respectively. The subtype A1 sequences formed one large cluster, which also included sequences from other parts of the former Soviet Union (FSU), whereas most subtype B sequences formed three distinct clusters. We estimated that subtype A1 was introduced from FSU around 1997 and initially spread explosively among IDUs in Riga. A recent increase of heterosexually infected persons did not form a separate subepidemic, but had multiple interactions with the IDU epidemic. Subtype B was introduced before the collapse of the Soviet Union and primarily has spread among men who have sex with men.

Low prevalence of transmitted drug resistance among newly diagnosed HIV-1 patients in Latvia

Transmitted drug resistance (TDR) is a concern because it may reduce the efficacy of antiretroviral treatment. Plasma samples of 119 HIV-1-infected patients who were newly diagnosed at the Infectology Center of Latvia in 2005 and 2006 were analyzed by an in-house genotypic resistance assay to determine the prevalence of TDR in Latvia. TDR was identified using the WHO 2009 list of mutations for surveillance of TDR as implemented in the Stanford Calibrated Population Resistance tool. Neighbor-joining phylogenetic analyses were used to determine genetic subtype and investigate the relatedness of the sequences. Resistance testing was successful in 117 of 119 patients. The study population represented ∼20% of all patients that were diagnosed in Latvia in 2005 and 2006 and was well distributed between gender, transmission routes, and areas of residence. Four patients showed evidence of TDR, which represents a prevalence of TDR of 3.4% (95% CI: 0.9-8.5%). All four patients displayed single, but different resistance mutations (M46I, F53L, M41L, and G190A). All patients, except one, were predicted to respond well to standard first-line therapy in Latvia. The prevalence of TDR in Latvia was low, which partly may be due to the low proportion of HIV-1 patients who receive antiretroviral therapy. The results indicate that routine resistance testing in Latvia currently should be focused on patients who display treatment failure, rather than treatment naive patients.

HIV drug resistance tendencies in Latvia

The treatment of HIV infection in Latvia by using highly active antiretroviral therapy (HAART) was started in 1996. The prevalence and tendencies of HIV drug resistance among treated and treatment-naive patients in Latvia in the years 2006-2007 were evaluated in this study. Data of HIV genotyping, performed in 132 HIV-1 infected during years 2006-2007 by TRUGENE HIV-1 genotyping assay (BayerHealthCare-diagnostics) are included in the study. Analysis of data showed that in the group of treatment-naive individuals majority carried wild type virus. Prevalence of resistance-associated mutations (RAMs) in the treatment-naive group according to IAS list was 28%. In most cases it was NRTI mutation A62V that is associated with multinucleoside resistance caused by Q151M, its effect in the absence of Q151M is not known. By many authors A62V is supposed to be a result of polymorphism in RT gene and is excluded from the list of resistance mutations. High prevalence of A62V is typical for HIV-1 subtype A. As majority of treatment-naive cases (89%) in this study were with HIV-1 subtypes A or AE, we excluded A62V mutation and estimated RAMs prevalence in group of treatment-naive HIV-infected individuals as 7%. Minor PI mutations were not included in analyses. In Europe published rates generally very between 5% and 15%. In the group of treatment-experienced HIV infected people 25/75 were with HIV-1 subtype B, the rest part--with non-B subtypes: A/AE (35/75), CRF-01AE (7/75), B/AE (4/75) and others. In treatment-experienced patients RAMs prevalence was estimated as 58.6%. Most frequently RAMs were found for nucleoside reverse transcriptase inhibitors (NRTI) (49.3%) followed by non-nucleoside reverse transcriptase inhibitors (NNRTI) (22.6%) and protease inhibitors (PI) (16%). In the group of NRTI mutations M184V (26/75; 34.6%), A62V (12/75; 16.0%) and T215Y (8/75; 10.6%), in NNRTI mutations K103N (10/75; 13.3%), G190S (6/75; 8.0%), in PI group mutations L90M (6/75; 8.0%) and M461/L (6/75; 8.0%) occurred most frequently. The following drug susceptibility was predicted according to the Trugen expert interpretations: in 33/75 (44%) patients no evidence of resistance, in 21/75 (28%) patients resistance to 1 drug class (NRTI--16/75, NNRTI--4/75, PI--1/75), in 17 patients (22.6%) resistance to 2 drug classes (NRTI+NNRTI--9/75, NRTI+PI--7/75, NNRTI+PI--1/75) and in 3/75 (4%) patients resistance to all 3 classes of drugs (NRTI+NNRTI+PI). We conclude, that prevalence of RAMs in treatment-naive HIV infected persons in Latvia is comparable with prevalence in Europe. The origin of predominated mutation A62V associated with NRTI at present is not clear. In more than half of treated HIV infected patients HIV resistance to at least one HAART class was predicted.

Rapid epidemic spread of HIV type 1 subtype A1 among intravenous drug users in Latvia and slower spread of subtype B among other risk groups

To investigate the rapid HIV epidemic in Latvia, 97 newly detected individuals were sampled in 2000-2001. To establish the molecular epidemiology we sequenced the env V3 and gag p17 regions of the HIV genome and compared them with reference sequences using phylogenetic analyses. As expected, the vast majority (n = 88; 91%) were intravenous drug users (IDUs) from the Riga region. Also, the majority of the investigated individuals (n = 93; 96%) were found to carry a subtype A1 virus that may have entered the Latvian IDU population several times. In addition, one IDU was infected with CRF03_AB and three other individuals, who had been infected through sexual contacts, carried subtype B virus. Thus, subtype A1 dominates the Latvian epidemic and is strongly associated with the IDU risk group. Although some spread of subtype A1 has occurred in the heterosexual group, subtype B dominates among homosexually and heterosexually infected individuals.