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.

Securing Wider EU Commitment to the Elimination of HCV.

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 programs - from the municipality level to the EU level - were launched, resulting in an overall decrease of 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 3rd 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 report 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.

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.

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.

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.

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.

Comparative Immunogenicity of BNT162b2 mRNA Vaccine with Natural SARS-CoV-2 Infection.

BNT162b2 has proven to be highly effective, but there is a paucity of data regarding immunogenicity factors and comparison between response to vaccination and natural infection. This study included 871 vaccinated healthcare workers (HCW) and 181 patients with natural infection. Immunogenicity was assessed by measuring anti-SARS-CoV-2 against the RBD domain of the spike protein (anti-RBD). Samples were collected 1-2 weeks after vaccination or 15-59 days post-onset of symptoms. Post-vaccine anti-RBD concentrations were associated with age, gender, vaccination side-effects (VSE) and prior infection (Pr-CoV). Anti-RBD median levels (95%CI) were lower by 2466 (651-5583), 6228 (3254-9203) and 7651 (4479-10,823) AU/mL in 35-44, 45-54, 55-70 yrs, respectively, compared with the 18-34 yrs group. In females, the median levels were higher by 2823 (859-4787), 5024 (3122-6926) in individuals with VSE, and 9971 (5158-14,783) AU/mL in HCWs with Pr-CoV. The ratio of anti-RBD in vaccinated individuals versus those with natural infection varied from 1.0 to 19.4. The high immunogenicity of BNT162b2 is verified, although its sustainability has yet to be elucidated. The use of comparative data from natural infection serological panels, expressing the clinical heterogeneity of natural infection, may facilitate early decisions for candidate vaccines to be evaluated in clinical trials.

Molecular Epidemiology of SARS-CoV-2 in Greece Reveals Low Rates of Onward Virus Transmission after Lifting of Travel Restrictions Based on Risk Assessment during Summer 2020.

The novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spread rapidly during the first months of 2020 and continues to expand in multiple areas across the globe. Molecular epidemiology has provided an added value to traditional public health tools by identifying SARS-CoV-2 clusters or providing evidence that clusters based on virus sequences and contact tracing are highly concordant. Our aim was to infer the levels of virus importation and to estimate the impact of public health measures related to travel restrictions to local transmission in Greece. Our phylogenetic and phylogeographic analyses included 389 full-genome SARS-CoV-2 sequences collected during the first 7 months of the pandemic in Greece and a random collection in five replicates of 3,000 sequences sampled globally, as well as the best hits to our data set identified by BLAST. Phylogenetic trees were reconstructed by the maximum likelihood method, and the putative source of SARS-CoV-2 infections was inferred by phylogeographic analysis. Phylogenetic analyses revealed the presence of 89 genetically distinct viruses identified as independent introductions into Greece. The proportion of imported strains was 41%, 11.5%, and 8.8% during the three periods of sampling, namely, March (no travel restrictions), April to June (strict travel restrictions), and July to September (lifting of travel restrictions based on thorough risk assessment), respectively. The results of phylogeographic analysis were confirmed by a Bayesian approach. Our findings reveal low levels of onward transmission from imported cases during summer and underscore the importance of targeted public health measures that can increase the safety of international travel during a pandemic. IMPORTANCE Our study based on current state-of-the-art molecular epidemiology methods suggests that virus screening and public health measures after the lifting of travel restrictions prevented SARS-CoV-2 onward transmission from imported cases during summer 2020 in Greece. These findings provide important data on the efficacy of targeted public health measures and have important implications regarding the safety of international travel during a pandemic. Our results can provide a roadmap about prevention policy in the future regarding the reopening of borders in the presence of differences in vaccination coverage, the circulation of the virus, and the presence of newly emergent variants across the globe.

Reactivation of Varicella Zoster Virus after Vaccination for SARS-CoV-2.

Seven immunocompetent patients aged > 50 years old presented with herpes zoster (HZ) infection in a median of 9 days (range 7-20) after vaccination against SARS-CoV-2. The occurrence of HZ within the time window 1-21 days after vaccination defined for increased risk and the reported T cell-mediated immunity involvement suggest that COVID-19 vaccination is a probable cause of HZ. These cases support the importance of continuing assessment of vaccine safety during the ongoing massive vaccination for the COVID-19 pandemic and encourage reporting and communication of any vaccination-associated adverse event.

Effects of Social Distancing Measures during the First Epidemic Wave of Severe Acute Respiratory Syndrome Infection, Greece.

Greece imposed a nationwide lockdown in March 2020 to mitigate transmission of severe acute respiratory syndrome coronavirus 2 during the first epidemic wave. We conducted a survey on age-specific social contact patterns to assess effects of physical distancing measures and used a susceptible-exposed-infectious-recovered model to simulate the epidemic. Because multiple distancing measures were implemented simultaneously, we assessed their overall effects and the contribution of each measure. Before measures were implemented, the estimated basic reproduction number (R0) was 2.38 (95% CI 2.01-2.80). During lockdown, daily contacts decreased by 86.9% and R0 decreased by 81.0% (95% credible interval [CrI] 71.8%-86.0%); each distancing measure decreased R0 by 10%-24%. By April 26, the attack rate in Greece was 0.12% (95% CrI 0.06%-0.26%), one of the lowest in Europe, and the infection fatality ratio was 1.12% (95% CrI 0.55%-2.31%). Multiple social distancing measures contained the first epidemic wave in Greece.

Antibodies against SARS-CoV-2 among health care workers in a country with low burden of COVID-19.

INTRODUCTION: Greece is a country with limited spread of SARS-CoV-2 and cumulative infection attack rate of 0.12% (95% CI 0.06-0.26). Health care workers (HCWs) are a well-recognized risk group for COVID-19. The study aimed to estimate the seroprevalence of antibodies to SARS-CoV-2 in a nosocomial setting and assess potential risk factors. METHODS: HCWs from two hospitals participated in the study. Hospital-1 was a tertiary university affiliated center, involved in the care of COVID-19 patients while hospital-2 was a tertiary specialized cardiac surgery center not involved in the care of these patients. A validated, CE, rapid, IgM/IgG antibody point-of-care test was used. Comparative performance with a reference globally available assay was assessed. RESULTS: 1,495 individuals consented to participate (response rate 77%). The anti-SARS-CoV-2 weighted prevalence was 1.26% (95% CI 0.43, 3.26) overall and 0.53% (95% CI 0.06, 2.78) and 2.70% (95% CI 0.57, 9.19) in hospital-1 and hospital-2, respectively although the study was underpowered to detect statistically significant differences. The overall, hospital-1, and hospital-2 seroprevalence was 10, 4 and 22 times higher than the estimated infection attack rate in general population, respectively. Suboptimal use of personal protective equipment was noted in both hospitals. CONCLUSIONS: These data have implications for the preparedness of a second wave of COVID-19 epidemic, given the low burden of SARS-CoV-2 infection rate, in concordance with national projections.