Incidence of primary hepatitis C infection among people who inject drugs during 2012-2020 in Athens, Greece.

One of the World Health Organization's targets for the 2030 viral hepatitis elimination strategy is to reduce new hepatitis C (HCV) infections. In Athens, Greece, people who inject drugs (PWID) have a high HCV prevalence, with increasing trends since the 2000s. This analysis aims to assess primary HCV incidence among PWID during 2012-2020. Two community-based interventions were implemented in 2012-2013 and 2018-2020 with repeated sero-behavioural surveys in each period. Participants enrolled in multiple surveys were identified through linkage. To assess trends in HCV transmission, three indicators were estimated: (i) anti-HCV prevalence among 'new' injectors (those injecting ≤2 years), (ii) indirect HCV incidence among 'new' injectors, assuming infection occurred at the midpoint between initiating injection and the first positive test, and (iii) HCV incidence from repeat participants. There were 431 and 125 'new' injectors, respectively, in 2012-2013 and 2018-2020. Αnti-HCV prevalence [95% CI] declined from 53.6% [48.8%, 58.3%] in 2012-2013 to 40.0% [31.3, 49.1%] in 2018-2020 (25.4% reduction, p = .007). The indirect estimate [95% CI] of HCV incidence among 'new' injectors decreased from 56.1 [49.3, 63.8] to 39.0/100 person-years (PYs) [29.6, 51.5] (30.5% reduction, p = .020). HCV incidence [95% CI] based on seroconversions in repeat participants (16/63 in 2012-2013 and 9/55 in 2018-2020) declined from 64.6 [39.6105.4] to 13.8/100 PYs [7.2, 26.5], respectively (78.6% reduction, p < .001). Primary HCV incidence remains high among PWID in Athens. Consistent implementation of combined interventions, including high-coverage harm reduction programs and initiatives tailored to increase access to HCV treatment, is essential to sustain the declining trends documented during 2012-2020.

Molecular epidemiology of HIV among people who inject drugs after the HIV-outbreak in Athens, Greece: Evidence for a 'slow burn' outbreak.

BACKGROUND: New diagnoses of HIV-1 infection among people who inject drugs (PWID) in Athens, Greece, saw a significant increase in 2011 and a subsequent decline after 2013. Despite this, ongoing HIV-1 transmission persisted from 2014 to 2020 within this population. Our objective was to estimate the time of infection for PWID in Athens following the HIV-1 outbreak, explore the patterns of HIV-1 dispersal over time, and determine the duration from infection to diagnosis. METHODS: Time from HIV-1 infection to diagnosis was estimated for 844 individuals infected within 4 PWID-specific clusters and for 8 PWID infected with sub-subtype A6 diagnosed during 2010-2019. Phylogeny reconstruction was performed using the maximum-likelihood method. HIV-1 infection dates were based on molecular clock calculations. RESULTS: In total 86 of 92 (93.5%) sequences from PWID diagnosed during 2016-2019 were either related to the previously identified PWID-specific clusters (n = 81) or belonged to a new A6 cluster (n = 5). The median time between infection and diagnosis was 0.42 years during the outbreak period and 0.70 years during 2016-2019 (p < 0.001). The proportion of clustered sequences from PWID was very low at 5.3% during the pre-outbreak period (1998-2009), saw an increase to 41.7% one year before the outbreak in 2010, and consistently remained high during the whole period after 2011, spanning the post-outbreak period (2016-2019) with a range from 92.9% to 100%. CONCLUSIONS: The substantial proportion of clustered infections (93.5%) during 2016-2019 implies a persistent 'slow burn' HIV outbreak among PWID in Athens, suggesting that the outbreak was not successfully eliminated. The consistently high proportion of clustered sequences since the onset of the outbreak suggests the persistence of ongoing HIV-1 transmission attributed to injection practices. Our findings underscore the importance of targeted interventions among PWID, considering the ongoing transmission rate and prolonged time from infection to diagnosis.

High levels of all-cause mortality among people who inject drugs from 2018 to 2022.

BACKGROUND: Mortality among people who inject drugs (PWID) is high, with overdose and HIV infection being the main causes of death. In Greece, there have been no data on mortality, and two HIV outbreaks have been recorded in this population in the past decade. In this study, we aim to estimate the all-cause crude mortality rate and the standardised mortality ratio in this population during 2018-2022. METHODS: PWID recruited from two community-based programs in Athens and Thessaloniki during 2018-2021 were interviewed and tested for HIV/HCV. Data on vital status (deceased/alive) and date of death were obtained from death registries through December 31, 2022. All-cause crude mortality rates (CMR) and standardised mortality ratios (SMR) were estimated. Determinants of mortality were assessed using Cox proportional-hazards model. RESULTS: Of 2,530 participants, 301 died over 8,543 person-years (PYs) of follow-up. The CMR (95 % CI) was 3.52 (3.15-3.94) deaths per 100 PYs; 3.10 per 100 PYs (2.68-3.58) in Athens and 4.48 per 100 PYs (3.74-5.37) in Thessaloniki. An increasing trend in CMR was identified over 2018-2022 in Athens (from 2.90 to 4.11 per 100 PYs, 41.5 % increase, p = 0.018). The pooled SMR (95 % CI) was 15.86 (14.17-17.76) for both cities and was particularly increased in younger individuals, females, those injecting daily, not enrolled to opioid agonist treatment and HIV-infected individuals. Older age, living in Thessaloniki, Greek origin, homelessness, history of injection in the past 12 months, and HIV infection were independently associated with higher risk of death. CONCLUSION: Mortality among PWID in the two largest cities (Athens and Thessaloniki) in Greece in 2018-2022 was high, with the population in Thessaloniki being particularly affected. The increasing trend in mortality in Athens may reflect the long-term impact of the COVID-19 pandemic. Preventive programs such as take-home naloxone, screening and treatment for HIV, are urgently needed.

Incarceration history is associated with HIV infection among community-recruited people who inject drugs in Europe: A propensity-score matched analysis of cross-sectional studies.

AIMS: We measured the association between a history of incarceration and HIV positivity among people who inject drugs (PWID) across Europe. DESIGN, SETTING AND PARTICIPANTS: This was a cross-sectional, multi-site, multi-year propensity-score matched analysis conducted in Europe. Participants comprised community-recruited PWID who reported a recent injection (within the last 12 months). MEASUREMENTS: Data on incarceration history, demographics, substance use, sexual behavior and harm reduction service use originated from cross-sectional studies among PWID in Europe. Our primary outcome was HIV status. Generalized linear mixed models and propensity-score matching were used to compare HIV status between ever- and never-incarcerated PWID. FINDINGS: Among 43 807 PWID from 82 studies surveyed (in 22 sites and 13 countries), 58.7% reported having ever been in prison and 7.16% (n = 3099) tested HIV-positive. Incarceration was associated with 30% higher odds of HIV infection [adjusted odds ratio (aOR) = 1.32, 95% confidence interval (CI) = 1.09-1.59]; the association between a history of incarceration and HIV infection was strongest among PWID, with the lowest estimated propensity-score for having a history of incarceration (aOR = 1.78, 95% CI = 1.47-2.16). Additionally, mainly injecting cocaine and/or opioids (aOR = 2.16, 95% CI = 1.33-3.53), increased duration of injecting drugs (per 8 years aOR = 1.31, 95% CI = 1.16-1.48), ever sharing needles/syringes (aOR = 1.91, 95% CI = 1.59-2.28) and increased income inequality among the general population (measured by the Gini index, aOR = 1.34, 95% CI = 1.18-1.51) were associated with a higher odds of HIV infection. Older age (per 8 years aOR = 0.84, 95% CI = 0.76-0.94), male sex (aOR = 0.77, 95% CI = 0.65-0.91) and reporting pharmacies as the main source of clean syringes (aOR = 0.72, 95% CI = 0.59-0.88) were associated with lower odds of HIV positivity. CONCLUSIONS: A history of incarceration appears to be independently associated with HIV infection among people who inject drugs (PWID) in Europe, with a stronger effect among PWID with lower probability of incarceration.

A new outbreak of HIV infection among people who inject drugs during the COVID-19 pandemic in Greece.

BACKGROUND: Multiple HIV outbreaks have been recorded among people who inject drugs (PWID) since 2010. During an intervention for PWID in 2019-2021 in Thessaloniki, Greece, an increasing number of HIV cases was documented. Here, we provide an analysis of this new outbreak. METHODS: ALEXANDROS was a community-based program and participation included interviewing, rapid HIV/HCV tests, counselling and linkage to care. PWID were recruited through Respondent-Driven Sampling (RDS) in five sampling rounds. Crude and RDS-weighted HIV prevalence estimates were obtained. HIV incidence was estimated from data on 380 initially seronegative PWID with at least two tests. Multivariable Cox proportional hazards model was used to assess risk factors for HIV seroconversion. RESULTS: In total, 1,101 PWID were recruited. At first participation, 53.7% were current PWID, 20.1% homeless, 20.3% on opioid substitution treatment and 4.8% had received syringes in the past 12 months. HIV prevalence (95% CI) was 7.0% (5.6-8.7%) and an increasing trend was observed over 2019-2021 (p = 0.002). Two-thirds of the cases (67.5%) were new diagnoses. HIV incidence was 7.0 new infections/100 person-years (95% CI:4.8-10.2). Homelessness in the past 12 months (HR:2.68; 95% CI:1.24-5.81) and receptive syringe sharing (HR:3.86; 95% CI:1.75-8.51) were independently associated with increased risk of seroconversion. By the end of the program, 67.3% of the newly diagnosed cases initiated antiretroviral treatment. CONCLUSIONS: A new HIV outbreak among PWID was documented in Greece during the COVID-19 pandemic with homelessness and syringe sharing being associated with increased risk of HIV acquisition. Peer-driven programs targeting the population of high-risk underserved PWID can be used to early identify emerging outbreaks and to improve linkage to HIV care.

Assessment of mRNA Vaccine Immunogenicity in Solid Organ Transplant Recipients.

Background and Objectives: Solid organ transplant (SOT) recipients have a higher risk of suffering from severe Coronavirus (COVID-19) compared to the general population. Studies have shown impaired immunogenicity of mRNA vaccines in this high-risk population; thus, SOT recipients have been prioritized globally for primary and booster doses. Materials and Methods: We analyzed 144 SOT recipients who had previously received two doses of BNT162b2 or mRNA1273 vaccine, and who were subsequently vaccinated with a booster dose of the mRNA1273 vaccine. Humoral and cellular immune responses were measured 1 and 3 months after the second dose, and 1 month after the third dose. Results: One month after the second dose, 33.6% (45/134) of patients displayed a positive antibody response with a median (25th, 75th) antibody titer of 9 (7, 161) AU/mL. Three months after the second dose, 41.8% (56/134) tested positive with a median (25th, 75th) antibody titer of 18 (7, 251) AU/mL. After the booster dose, the seropositivity rate increased to 69.4% (93/134), with a median (25th, 75th) titer of 966 (10, 8027) AU/mL. The specific SARS-CoV-2 T-cell response was assessed in 44 randomly selected recipients 3 months after the second dose, and 11.4% (5/44) of them had a positive response. Following the third dose, 42% (21/50) tested positive. Side effects after the third dose were mild, with pain at the injection site being the most frequent adverse effect, reported by 73.4% of the recipients. Conclusion: Our study shows a mild delayed increase in antibody titer, three months after primary vaccination compared to one month after. It also shows a robust augmentation of humoral and specific T-cell responses after the booster dose, as well as the safety and tolerability of the mRNA vaccines in SOT recipients.

HIV RNA/DNA Levels at Diagnosis Can Predict Immune Reconstitution: A Longitudinal Analysis.

BACKGROUND: HIV DNA mirrors the number of infected cells and the size of the HIV viral reservoir. The aim of this study was to evaluate the effect of pre-cART HIV DNA levels as a predictive marker of immune reconstitution and on the post-cART CD4 counts trends. METHODS: HIV DNA was isolated from PBMCs and quantified by real-time PCR. Immune reconstitution was assessed up to four years. Piecewise-linear mixed models were used to describe CD4 count changes. RESULTS: 148 people living with HIV (PLWH) were included. The highest rate of immune reconstitution was observed during the first trimester. There was a trend showing that high HIV RNA level resulted in greater increase in CD4 count, especially during the first trimester of cART (difference above vs. below median 15.1 cells/µL/month; 95% CI -1.4-31.5; p = 0.073). Likewise, higher HIV DNA level would predict greater CD4 increases, especially after the first trimester (difference above vs. below median 1.2 cells/µL/month; 95% CI -0.1-2.6; p = 0.071). Higher DNA and RNA levels combined were significantly associated with greater CD4 increase past the first trimester (difference high/high vs. low/low 2.1 cells/µL/month; 95% CI 0.3-4.0; p = 0.024). In multivariable analysis, lower baseline CD4 counts predicted a greater CD4 rise. CONCLUSIONS: In successfully treated PLWH, pre-cART HIV DNA and HIV RNA levels are predictors of immune reconstitution.

Estimating the number of people who inject drugs using repeated respondent-driven sampling (RDS) in a community-based program: implications for the burden of hepatitis C and HIV infections and harm reduction coverage.

Estimates of the population size of people who inject drugs (PWID) are essential for efficient program planning and for monitoring key targets. Existing estimates in Greece are based on the capture-recapture method applied to drug treatment sources. We aimed to obtain estimates based on data collected from a community-based program addressing PWID in Athens, Greece. The program was implemented in 2012-2013 to increase diagnosis and treatment for HIV among PWID during an HIV outbreak. Five Responden-Driven Sampling (RDS) rounds were used to recruit participants. A unique code was used to identify participants among rounds. Capture-recapture was applied to estimate the population size in 2013 (PWID with injection in the past 12 months; active PWID with injection in the past 30 days). Log-linear models were applied. In 2013, the estimated number of active PWID in Athens was 4,117 [95% confidence interval (CI): 3,728-4,507] (vs. 1,956 [95% CI: 1,525-2,565] the existing population size estimate). Based on this estimate, the coverage of needle and syringe programs in 2013 was 103 syringes/PWID/year (vs. 216 based on the existing estimate). The population prevalence of injecting drug use in Athens (past 12 months) was 0.222% (95% CI: 0.200-0.245). The inclusion of data from community-based programs in the estimation of the PWID population size resulted in 2.1-fold higher estimates, compared to the official estimates obtained from drug treatment data, and indicates the need for re-evaluation of necessary resources for harm reduction and elimination of HIV and hepatitis C in PWID.

Securing wider EU commitment to the elimination of hepatitis C virus.

In 2016, the Hepatitis B and C Public Policy Association (HepBCPPA), gathered all the main stakeholders in the field of hepatitis C virus (HCV) to launch the now landmark HCV Elimination Manifesto, calling for the elimination of HCV in the EU by 2030. Since then, many European countries have made progress towards HCV elimination. Multiple programmes-from the municipality level to the EU level-were launched, resulting in an overall decrease in viremic HCV infections and liver-related mortality. However, as of 2021, most countries are not on track to reach the 2030 HCV elimination targets set by the WHO. Moreover, the COVID-19 pandemic has resulted in a decrease in HCV diagnoses and fewer direct-acting antiviral treatment initiations in 2020. Diagnostic and therapeutic tools to easily diagnose and treat chronic HCV infection are now well established. Treating all patients with chronic HCV infection is more cost-saving than treating and caring for patients with liver-related complications, decompensated cirrhosis or hepatocellular carcinoma. It is more important than ever to reinforce and scale-up action towards HCV elimination. Yet, efforts urgently need the dedicated commitment of policymakers at all governmental and policy levels. Therefore, the third EU Policy Summit, held in March 2021, featured EU parliamentarians and other key decision makers to promote dialogue and take strides towards securing wider EU commitment to advance and achieve HCV elimination by 2030. We have summarized the key action points and reported the 'Call-to-Action' statement supported by all the major relevant European associations in the field.

Immunogenicity of the Two mRNA SARS-CoV-2 Vaccines in a Large Cohort of Dialysis Patients.

Chronic kidney disease patients, especially those on hemodialysis, are at the highest risk of a severe course and death from COVID-19. Moreover, they appear to have suboptimal response in both cellular and humoral immunity after vaccination. The present study investigated humoral and cellular response and safety after two doses of either of the two authorized mRNA vaccines in a cohort of 310 patients on maintenance dialysis. The antibody response rate was 94.5%, with a median (25th, 75th) antibody titer of 3478 (1236, 8141) AU/mL. Only mild adverse effects were observed. Only vaccine type was independently associated with immunogenicity. Α statistically significant difference in favor of mRNA1273 versus BNT162b2 vaccine was observed. Antibody positivity (100% vs. 94.3%, p < 0.001), median (25th, 75th) antibody levels: 9499 (6118, 20,780) AU/mL vs. 3269 (1220, 7807) AU/mL (p < 0.001). Among the 65 patients tested for T-cell response, 27 (41.5%) had a positive one with a median (25th, 75th) antibody titer of 6007 (3405, 12,068) AU/mL, while 38 with no T-cell response presented a lower median (25th, 75th) antibody titer of 1744 (850, 4176) AU/mL (p < 0.001). Both mRNA vaccines are safe for dialysis patients and can trigger humoral and cellular responses, although with lower titers than those that have been reported to healthy individuals.

Immunogenicity of a third dose of the BNT162b2 COVID-19 vaccine in patients with CLL: effects on treatment selection.

Patients with chronic lymphocytic leukemia (CLL) show suboptimal responses to the vaccines against SARS-CoV-2; it has been shown though that a booster dose of the BNT162b2 vaccine may lead to a significant increase in the seroconversion rates of immunocompromised patients. We conducted a prospective, non-interventional study to evaluate the immunogenicity of a third dose of the BNT162b2 vaccine in adult patients with CLL. Sera were tested before the first, after the second, and before and after the third dose for anti-SARS-CoV-2 receptor binding domain (RBD) spike protein IgG (anti-RBD). Thirty-nine patients with CLL were included in the study. The seroconversion rate increased from 28.2% before the third dose to 64.1% after the third dose and was higher in treatment-naïve patients (72.7% versus 47.1% in actively treated patients, p = 0.042). All but one patient achieving a seroconversion after the second dose retained after the third, while eight patients not achieving a seroconversion after the second dose (38.1%), did so after the third. Moreover, patients actively treated with venetoclax had a higher seroconversion rate than those treated with ibrutinib (87.5% versus 14.3%, p = 0.001). This study confirms the beneficial effect of a third dose of the BNT162b2 vaccine on the seroconversion rate in patients with CLL. Our results also strongly suggest that the use of venetoclax is correlated with higher immunogenicity/seroconversion rates than that of ibrutinib, a finding that has been reported by another study. A treatment strategy change during the pandemic favoring the use of venetoclax may be suggested based on our results, although these results should be validated in larger studies.

Estimation of the determinants for HIV late presentation using the traditional definition and molecular clock-inferred dates: Evidence that older age, heterosexual risk group and more recent diagnosis are prognostic factors.

OBJECTIVES: HIV late presentation (LP) has been increasing in recent years in Europe. Our aim was to investigate the characteristics of LP in Greece using in addition to the traditional definition for LP, the time interval between HIV infection and diagnosis. METHODS: Our nationwide sample included HIV-1 sequences generated from 6166 people living with HIV (PLWH) in Greece during the period 1999-2015. Our analysis was based on the molecularly inferred HIV-1 infection dates for PLWH infected within local molecular transmission clusters of subtypes A1 and B. RESULTS: Analysis of the determinants of LP was conducted using either CD4 counts or AIDS-defining condition at diagnosis or the time from infection to diagnosis. Older age, heterosexual transmission risk group and more recent diagnosis were associated with increased risk for LP. In contrast to previous studies, people who inject drugs (PWID) had a shorter median time to diagnosis (0.63 years) compared to men who have sex with men (MSM) (1.72 years) and heterosexuals (2.43 years). Using HIV infection dates that provide an unbiased marker for LP compared to CD4 counts at diagnosis, which are age-dependent, we estimated that the time to diagnosis increased gradually with age. Migrants infected regionally do not differ with respect to LP status compared to native Greeks. CONCLUSIONS: We demonstrate that older people and heterosexuals are among those at higher risk for LP; and given the growing number of older people among newly diagnosed cases, tailored interventions are needed in these populations.

Safety and immunogenicity of the BNT162b2 mRNA Covid-19 vaccine in patients with chronic lymphocytic leukemia: a prospective study.

Introduction: Immunization of patients with chronic lymphocytic leukemia (CLL) with vaccines against several infectious diseases has proven insufficient. Data on seroconversion of patients with CLL after vaccination against severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) are still young, but accumulating evidence shows low seroconversion rates. Methods: We conducted a prospective, noninterventional study evaluating the safety and immunogenicity of two doses of the BNT162b2 mRNA Covid-19 vaccine, administered 21 days apart in consecutive adult patients with CLL. Patients vaccinated with other vaccines against SARS-CoV-2, with a history of confirmed Coronavirus Disease 19 (COVID-19), with known human immunodeficiency virus infection, or with an inability to provide written informed consent were excluded. Sera were tested before the first and after the second dose of the vaccine for anti-SARS-CoV-2 receptor binding domain (RBD) spike protein IgG (anti-RBD), using the Abbott SARS-CoV-2 IgG II Quant assay (Abbott Laboratories, Abbott Park, IL, USA), with a cutoff value for seroconversion at 50 AU/ml. Results: Sixty-one patients (28 males/33 females) with CLL, with a median age of 61 years, were included in the study. The majority of the patients (82.0%) were lower (0-2) stage per the RAI staging system. The seroconversion rate at 14 days after the second dose was 45% and was correlated with RAI stage (0-2 versus 3-4; 51.0% versus 18.3%, p = 0.047), the treatment status (treatment naïve, previously treated, or actively treated patients; 63.0% versus 40.0% versus 26.1%, respectively, p = 0.031), the number of previous treatment lines (0-2 versus >2; 55.3% versus 8.3%, p = 0.004), and the platelet count of the patients (over or under 100 × 109/L; 52.9% versus 10.0%, p = 0.015). Moreover, there was a positive linear relationship between the antibody titers and the gamma-globulin levels (r = 0.182, p = 0.046) and platelet count (r = 0.277, p = 0.002). Finally, patients actively treated with venetoclax had higher antibody titers than those treated with ibrutinib (15.8 AU/ml versus 0.0 AU/ml, p = 0.047). No safety issues were identified while the emergence of adverse events was not correlated with immunogenicity. Discussion: This study confirms results from previous studies on the low seroconversion rates in patients with CLL vaccinated with the BNT162b2 mRNA Covid-19 vaccine and on the detrimental effect of advanced disease and multiple treatment lines on seroconversion, while it is suggested that treatment with venetoclax may offer a chance for higher antibody titers, suggesting a treatment strategy change during the pandemic provided that this result is confirmed by larger studies specifically designed to address this issue.

Modeling the impact of interventions during an outbreak of HIV infection among people who inject drugs in 2012-2013 in Athens, Greece.

BACKGROUND: A large HIV outbreak in People Who Inject Drugs (PWID) occurred in Athens, Greece in 2011-2013. In response, opioid substitution treatment (OST) and needle and syringe programs (NSP) were scaled-up and a seek-test-treat program was introduced in mid-2012. We aim to assess the impact of these interventions. METHODS: A mathematical model of HIV transmission among PWID was calibrated to data available over time (2009-2013) on HIV prevalence, NSP/antiretroviral treatment (ART) coverage and high-risk injection. A combined interventions scenario, including decrease in high-risk injection through linkage to OST and modification of risk behaviours and access to NSP and ART, was compared to a counterfactual scenario (no improvement at the levels of these interventions), with HIV incidence being the main outcome. RESULTS: HIV incidence increased from <0.1 new cases/100 person-years (in 2009) to 11.0 new cases/100 person-years (in 2012). Under both models, a subsequent decline was projected following early 2012, with incidence at the end of 2013 in the combined interventions scenario being lower by 77% compared to the counterfactual. The projected reduction in incidence under the intervention scenario was in agreement with empirical data. HIV prevalence would have escalated to 20.4% (95% CrI: 16.9%, 23.6%) in 2013 under the counterfactual scenario (vs. 16.8% (95% CrI: 11.2%, 23.0%) under the combined interventions scenario). In total, 31.4% of HIV cases (392) were averted over 2012-2013. CONCLUSION: These results underline the importance of high-coverage harm reduction programs and of community-based interventions to rapidly reach PWID most in need.

Immunogenicity of SARS-CoV-2 BNT162b2 Vaccine in People with Diabetes: A Prospective Observational Study.

The mRNA-based BNT162b2 vaccine has demonstrated high efficacy against severe SARS-CoV-2. However, data regarding immune response in people with diabetes mellitus (DM) after vaccination with the BNT162b2 vaccine are limited. In this prospective observational study, we examined humoral immune response in participants with and without DM after vaccination with the BNT162b2 mRNA vaccine. A total of 174 participants (58 with and 116 without diabetes, matched for age) were included. Antibodies were measured 21 days after the first dose, 7−15 days after the second dose, and 70−75 days after the second and before the third dose of the vaccine. Antibodies were measured by an anti-SARS-CoV-2 receptor-binding domain IgG (Abs-RBD-IgG) assay by a chemiluminescent microparticle immune assay; values > 50 AU/mL are considered protective from severe disease. Almost 17% of participants with DM did not develop adequate humoral immune response to the BNT162b2 mRNA vaccine after the first dose; however, it was high and similar after the second dose in both participants with and without DM and remained so almost 2 months after the second dose of the vaccine. Geometric mean values of Abs-RBD-IgG were not significantly different between participants with and without DM during the study. At least two doses of the BNT162b2 vaccine are necessary to ensure adequate and sustainable immune response in people with DM.

Trends in COVID-19 Vaccination Intent, Determinants and Reasons for Vaccine Hesitancy: Results from Repeated Cross-Sectional Surveys in the Adult General Population of Greece during November 2020-June 2021.

Vaccine hesitancy is a major barrier to achieving large-scale COVID-19 vaccination. We report trends in vaccination intention and associated determinants from surveys in the adult general population in Greece. Four cross-sectional phone surveys were conducted in November 2020 and February, April and May 2021 on nationally representative samples of adults in Greece. Multinomial logistic regression was used on the combined data of the surveys to evaluate independent predictors of vaccination unwillingness/uncertainty. Vaccination intention increased from 67.6% in November 2020 to 84.8% in May 2021. Individuals aged 65 years or older were more willing to be vaccinated (May 2021: 92.9% vs. 79.5% in 18−39 years, p < 0.001) but between age-groups differences decreased over time. Vaccination intention increased substantially in both men and women, though earlier among men, and was higher in individuals with prograduate education (May 2021: 91.3% vs. 84.0% up to junior high). From multivariable analysis, unwillingness and/or uncertainty to be vaccinated was associated with younger age, female gender (in particular in the April 2021 survey), lower educational level and living with a child ≤12 years old. Among those with vaccine hesitancy, concerns about vaccine effectiveness declined over time (21.6% in November 2020 vs. 9.6% in May 2021, p = 0.014) and were reported more often by men; safety concerns remained stable over time (66.3% in November 2020 vs. 62.1% in May 2021, p = 0.658) and were reported more often by women. In conclusion, vaccination intention increased substantially over time. Tailored communication is needed to address vaccine hesitancy and concerns regarding vaccine safety.

Head-to-Head Comparison of Response Rates to the Two mRNA SARS-CοV-2 Vaccines in a Large Cohort of Solid Organ Transplant (SOT) Recipients.

Due to their higher risk of developing life-threatening COVID-19 disease, solid organ transplant (SOT) recipients have been prioritized in the vaccination programs of many countries. However, there is increasing evidence of reduced immunogenicity to SARS-CοV-2 vaccination. The present study investigated humoral response, safety, and effectiveness after the two mRNA vaccines in 455 SOT recipients. Overall, the antibody response rate was low, at 39.6%. Higher immunogenicity was detected among individuals vaccinated with the mRNA1273 compared to those with the BNT162b2 vaccine (47% vs. 36%, respectively, p = 0.025) as well as higher median antibody levels of 31 (7, 372) (AU/mL) vs. 11 (7, 215) AU/mL, respectively. Among the covariates assessed, vaccination with the BNT162b2 vaccine, antimetabolite- and steroid-containing immunosuppression, female gender, the type of transplanted organ and older age were factors that negatively influenced immune response. Only mild adverse effects were observed. Our findings confirm poor immunogenicity after vaccination, implicating a reevaluation of vaccination policy in SOT recipients.

Modelling SARS-CoV-2 Binding Antibody Waning 8 Months after BNT162b2 Vaccination.

Several lines of evidence suggest that binding SARS-CoV-2 antibodies such as anti-SARS-CoV-2 RBD IgG (anti-RBD) and neutralising antibodies (NA) are correlates of protection against SARS-CoV-2, and the correlation of anti-RBD and NA is very high. The effectiveness (VE) of BNT162b2 in preventing SARS-CoV-2 infection wanes over time, and this reduction is mainly associated with waning immunity, suggesting that the kinetics of antibodies reduction might be of interest to predict VE. In a study of 97 health care workers (HCWs) vaccinated with the BNT162b2 vaccine, we assessed the kinetics of anti-RBD 30-250 days after vaccination using 388 individually matched plasma samples. Anti-RBD levels declined by 85%, 92%, and 95% at the 4th, 6th, and 8th month from the peak, respectively. The kinetics were estimated using the trajectories of anti-RBD by various models. The restricted cubic splines model had a better fit to the observed data. The trajectories of anti-RBD declines were statistically significantly lower for risk factors of severe COVID-19 and the absence of vaccination side effects. Moreover, previous SARS-CoV-2 infection was associated with divergent trajectories consistent with a slower anti-RBD decline over time. These results suggest that anti-RBD may serve as a harbinger for vaccine effectiveness (VE), and it should be explored as a predictor of breakthrough infections and VE.

A Network Approach to Determine Optimization of PrEP Uptake in Athens, Greece.

Although the HIV epidemic in Athens, Greece has reemerged and spread in men who have sex with men (MSM), state-supported PrEP programs have not been instituted. A PrEP intervention was implemented building upon an existing network cohort of MSM (308 participants; 1212 network members). A PrEP intervention cohort of 106 participants was selected based upon sex behaviors. Individual, partner, and network characteristics were compared between the cohorts. The PrEP cohort members were more highly connected and in more influential positions in the network than their peers. Further, their sexual network connections' behaviors increased their vulnerability to HIV infection relative to the rest of the network's sex partners. This included greater stimulant use (24.2% vs 7.0%; χ2 = 28.2; p < 0.001), greater rates of at least weekly condomless sex (OR = 2.7; 95% CI 2.1-3.5; χ2 = 59.2; p < 0.001) and at least weekly use of drugs or alcohol during sex (OR = 3.4; 95% CI 2.6-4.3; χ2 = 89.7; p < 0.001). Finally the PrEP cohort's social networks showed similarly increased vulnerability to seroconversion, including greater rates of injection drug use (4.1% vs 0.5%; χ2 = 3.9; p = 0.04), greater stimulant use (33.6% vs 14.6%; χ2 = 16.9, p < 0.001), and higher rates of recent STIs (21.6% vs 13.1%; χ2 = 4.4; p = 0.04). Thus, this PrEP intervention engaged individuals in vulnerable positions with vulnerable connections within an MSM community.

Dating the Origin and Estimating the Transmission Rates of the Major HIV-1 Clusters in Greece: Evidence about the Earliest Subtype A1 Epidemic in Europe.

Our aim was to estimate the date of the origin and the transmission rates of the major local clusters of subtypes A1 and B in Greece. Phylodynamic analyses were conducted in 14 subtype A1 and 31 subtype B clusters. The earliest dates of origin for subtypes A1 and B were in 1982.6 and in 1985.5, respectively. The transmission rate for the subtype A1 clusters ranged between 7.54 and 39.61 infections/100 person years (IQR: 9.39, 15.88), and for subtype B clusters between 4.42 and 36.44 infections/100 person years (IQR: 7.38, 15.04). Statistical analysis revealed that the average difference in the transmission rate between the PWID and the MSM clusters was 6.73 (95% CI: 0.86 to 12.60; p = 0.026). Our study provides evidence that the date of introduction of subtype A1 in Greece was the earliest in Europe. Transmission rates were significantly higher for PWID than MSM clusters due to the conditions that gave rise to an extensive PWID HIV-1 outbreak ten years ago in Athens, Greece. Transmission rate can be considered as a valuable measure for public health since it provides a proxy of the rate of epidemic growth within a cluster and, therefore, it can be useful for targeted HIV prevention programs.