Pietro Vernazza

• M.D.
• Head of Department at Kantonsspital St. Gallen

Background Genotypic resistance testing (GRT) is routinely performed upon diagnosis of HIV-1 infection or during virological failure using plasma viral RNA. An alternative source for GRT could be cellular HIV-1 DNA. Objectives A substantial number of participants in the Swiss HIV Cohort Study (SHCS) never received GRT. We applied a method that ena...

The effects of different types of pre-existing immunity on the frequency of clinical symptoms caused by the SARS-CoV-2 breakthrough infection were prospectively assessed in healthcare workers during the Omicron period. Among 518 participants, hybrid immunity was associated with symptom reduction for dizziness, muscle or limb pain and headache as co...

Background Echinacea purpurea has clinical antiviral activity against respiratory viruses and modulates immune functions. In this study, we compared higher doses of new Echinacea formulations with conventional formulations at lower, preventive doses for therapy of respiratory tract infections (RTIs). Methods In this randomized, blinded, controlled...

Background: Disentangling the effects of SARS-CoV-2 variants and vaccination on the occurrence of post-acute sequelae of SARS-CoV-2 (PASC) is crucial to estimate and reduce the burden of PASC. Methods: We performed a cross-sectional analysis (May/June 2022) within a prospective multicenter healthcare worker (HCW) cohort in North-Eastern Switzerl...

Background The effects of the com quorum sensing system during colonisation and invasion of Streptococcus pneumoniae (Spn) are poorly understood. Methods We developed an ex vivo model of differentiated human airway epithelial (HAE) cells with beating ciliae, mucus production and tight junctions to study Spn colonisation and translocation. HAE cell...

Importance Disentangling the effects of different SARS-CoV-2 variants and of vaccination on the occurrence of post-acute sequelae of SARS-CoV-2 (PASC) is crucial to estimate and potentially reduce the future burden of PASC. Objective To determine the association of primary SARS-CoV-2 infection on the frequency of PASC symptoms by viral variant and...

BACKGROUND Studying human immunodeficiency virus type 1 (HIV-1) superinfection is important to understand virus transmission, disease progression, and vaccine design. But detection remains challenging, with low sampling frequencies and insufficient longitudinal samples. METHODS Using the Swiss HIV Cohort Study (SHCS), we developed a molecular epide...

Rationale: Coronavirus disease 2019 (COVID-19) can lead to acute respiratory distress syndrome with fatal outcomes. Evidence suggests that dysregulated immune responses, including autoimmunity, are key pathogenic factors. Objectives: To assess whether IgA autoantibodies target lung-specific proteins and contribute to disease severity. Methods:...

Infectious diseases are particularly challenging for genome-wide association studies (GWAS) because genetic effects from two organisms (pathogen and host) can influence a trait. Traditional GWAS assume individual samples are independent observations. However, pathogen effects on a trait can be heritable from donor to recipient in transmission chain...

HIV-1 reservoir size and dynamics are promising parameters to ensure the safe prescription of simplified maintenance antiretroviral therapy in chronically HIV-1 infected patients. In the SIMPL’HIV trial, HIV-1 DNA was quantified in peripheral blood mononuclear cells obtained at baseline and week 48 to investigate changes over time and evidence of a...

Background: Studying HIV-1 superinfection is important to understand virus transmission, disease progression, and vaccine design. But detection remains challenging, with low sampling frequencies, and insufficient longitudinal samples. Methods: Using the Swiss HIV Cohort Study(SHCS), we developed a molecular epidemiology screening for superinfect...

Objectives: During the COVID-19 pandemic, few scientific congresses have been held on-site. We prospectively evaluated the safety concept of the congress of the Swiss Societies of Infectious Diseases and Hospital Hygiene. Methods: The congress was held in Geneva (Switzerland) while local COVID-19 incidence (with SARS-CoV-2 wild type circulating) wa...

Background There is insufficient evidence regarding the role of respirators in the prevention of SARS-CoV-2 infection. We analysed the impact of filtering facepiece class 2 (FFP2) versus surgical masks on the risk of SARS-CoV-2 acquisition among Swiss healthcare workers (HCW). Methods Our prospective multicentre cohort enrolled HCW from June to Au...

Background The burden of long-term symptoms (i.e. long-COVID) in patients after mild COVID-19 is debated. Within a cohort of healthcare workers (HCW), frequency and risk factors for symptoms compatible with long-COVID are assessed. Methods Participants answered baseline (August/September 2020) and weekly questionnaires on SARS-CoV-2 nasopharyngeal...

Myalgic encephalomyelitis (ME) or Chronic Fatigue Syndrome (CFS) is a neglected, debilitating multi-systemic disease without diagnostic marker or therapy. Despite evidence for neurological, immunological, infectious, muscular and endocrine pathophysiological abnormalities, the etiology and a clear pathophysiology remains unclear. The gut microbiome...

Streptococcus pneumoniae (Spn) colonises respiratory epithelia but can also invade lung cells causing pneumonia. We developed an ex vivo model with human airway epithelial (HAE) cells harvested from lung biopsies to study Spn colonisation and translocation. Flow-cytometry, confocal imaging and electron microscopy studies identified the epithelial l...

Certain immunizations including vaccination against tick-borne encephalitis virus (TBEV) have been suggested to confer cross-protection against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Within a prospective healthcare worker (HCW) cohort, we assessed the potentially protective role of anti-TBEV antibodies against SARS-CoV-2 infe...

Infectious diseases are a unique challenge for genome-wide association studies (GWAS) because pathogen, host, and environmental factors can all affect disease traits. Previous GWAS have successfully identified several human genetic variants associated with HIV-1 set point viral load (spVL), among other important infectious disease traits. However,...

Background The burden of long-term symptoms (i.e. long-COVID) in patients after mild COVID-19 is debated. Within a cohort of healthcare workers (HCW), frequency and risk factors for symptoms compatible with long-COVID are assessed. Methods Participants answered baseline (August/September 2020) and weekly questionnaires on SARS-CoV-2 nasopharyngeal...

Background In a prospective healthcare worker (HCW) cohort, we assessed the risk of SARS-CoV-2 infection according to baseline serostatus. Methods Baseline serologies were performed among HCW from 23 Swiss healthcare institutions between June and September 2020, before the second COVID-19 wave. Participants answered weekly electronic questionnaire...

BACKGROUND The implementation of novel techniques represents an additional opportunity for the rapid analysis acting as a complement to the traditional disease surveillance systems. OBJECTIVE The objective of this work is to describe a web-based participatory surveillance strategy among healthcare workers (HCW) in two Swiss hospitals during the fi...

Background: The implementation of novel techniques represents an additional opportunity for the rapid analysis acting as a complement to the traditional disease surveillance systems. Objective: The objective of this work is to describe a web-based participatory surveillance strategy among healthcare workers (HCW) in two Swiss hospitals during th...

Objectives Chronic hepatitis C virus (HCV) infection affects the immune system. Whether elimination of HCV with direct-acting antivirals (DAA) restores immunity is unclear. We used mass cytometry to get a broad and in-depth assessment of blood cell populations of patients with chronic HCV prior to and after DAA therapy. Methods Before and 12 weeks...

Background As trans women are disproportionately affected by the HIV epidemic, and are still understudied, we aimed to identify and characterize the trans women in the Swiss HIV Cohort Study (SHCS). Methods A combination of criteria from pre-existing cohort data was used to identify trans women. Information on socioeconomic factors, clinical data,...

Background: In Switzerland, HIV-1 transmission among men who have sex with men (MSM) has been dominated by subtype B, whilst non-B subtypes are commonly attributed to infections acquired abroad among heterosexuals. Here, we evaluated the temporal trends of non-B subtypes and the characteristics of molecular transmission clusters (MTCs) among MSM....

Objectives In a prospective healthcare worker (HCW) cohort, we assessed the risk of SARS-CoV-2 infection according to baseline serostatus. Methods Baseline serologies were performed among HCW from 23 Swiss healthcare institutions between June and September 2020, before the second COVID-19 wave. Participants answered weekly electronic questionnaires...

Background There is insufficient evidence regarding the role of respirators in the prevention of SARS-CoV-2 infection. We analysed the impact of filtering facepiece class 2 (FFP2) vs. surgical masks on the risk of SARS-CoV-2 acquisition among Swiss healthcare workers (HCW). Methods Our prospective multicentre cohort enrolled patient-facing HCWs fro...

Objectives Protecting healthcare workers (HCW) from Coronavirus Disease-19 (COVID-19) is critical to preserve the functioning of healthcare systems. We therefore assessed seroprevalence and identified risk factors for Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) seropositivity in this population. Methods Between June 22nd and Augus...

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

This study aims to evaluate the association between dolutegravir (DTG) pharmacokinetic parameters and weight changes in treatment‐experienced people with HIV (PWHIV) from the Simpl'HIV study newly switched to a dual DTG‐based regimen. We used multivariable linear regressions to evaluate the association between DTG pharmacokinetic parameters at week...

Background: In the future, co-circulation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza viruses A/B is likely. From a clinical point of view, differentiation of the two disease entities is crucial for patient management. We therefore aim to detect clinical differences between Coronavirus Disease 2019 (COVID-19) and...

Background: Hepatitis C virus (HCV) infections in Switzerland are mainly related to intravenous drug use. Since 2017, all patients with chronic hepatitis C can be treated with direct-acting antivirals (DAAs) irrespective of fibrosis stage. In March 2019, the Federal Office of Public Health (FOPH) published guidelines for HCV management in people w...

Complications affecting the lung are hallmarks of severe coronavirus disease 2019 (COVID-19). While there is evidence for autoimmunity in severe COVID-19, the exact mechanisms remain unknown. Here, we established a prospective observational cohort to study lung specific autoantibodies (auto-Abs). Incubation of plasma from severe COVID-19 patients w...

Several tests based on chemiluminescence immunoassay techniques have become available to test for SARS-CoV-2 antibodies. There is currently insufficient data on serology assay performance beyond 35 days after symptoms onset. We aimed to evaluate SARS-CoV-2 antibody tests on three widely used platforms. A chemiluminescent microparticle immunoassay (...

Background Worldwide, scientific congresses are cancelled because of the COVID-19 pandemic. Yet, scientific exchange is more important than ever, especially for infectious diseases and infection prevention specialists. Within a prospective cohort of congress attendees, we evaluated the safety concept of the 2020 congress of the Swiss Societies of I...

Background For the winter season 2020/2021, co-circulation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and influenza viruses A/B is expected. From a clinical point of view, differentiation of these two acute respiratory illnesses is crucial for optimal patient management. We therefore aimed to detect clinical differences between...

Objectives Understanding the drivers of HIV‐1 transmission is of importance for curbing the ongoing epidemic. Phylogenetic methods based on single viral sequences allow us to assess whether two individuals are part of the same viral outbreak, but cannot on their own assess who potentially transmitted the virus. We developed and assessed a molecular...

Pan-immunoglobulin assays can simultaneously detect IgG, IgM and IgA directed against the receptor binding domain (RBD) of the S1 subunit of the spike protein (S) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2 S1-RBD Ig). In this work, we aim to evaluate a quantitative SARS-CoV-2 S1-RBD Ig electrochemiluminescence immunoassay (ECLIA...

Background The extent of inappropriate prescribing observed in geriatric medicine has not been thoroughly evaluated in people ageing with HIV. We determined the prevalence of and risk factors for inappropriate prescribing in individuals aged ≥75 years enrolled in the Swiss HIV Cohort Study. Methods Retrospective review of medical records was perfo...

Approximately 28% of the human population have been exposed to Mycobacterium tuberculosis (MTB), with the overwhelming majority of infected individuals not developing disease (latent TB infection (LTBI)). While it is known that uncontrolled HIV infection is a major risk factor for the development of TB, the effect of underlying LTBI on HIV disease...

Knowledge of the sensitivities of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibody tests beyond 35 days after the clinical onset of COVID-19 is insufficient. We aimed to describe positivity rate of SARS-CoV-2 assays employing three different measurement principles over a prolonged period. Two hundred sixty-eight samples from 18...

Background Dolutegravir (DTG)–based dual therapy is becoming a new paradigm for both the initiation and maintenance of HIV treatment. The SIMPL’HIV study investigated the outcomes of virologically suppressed patients on standard combination antiretroviral therapy (cART) switching to DTG + emtricitabine (FTC). We present the 48-week efficacy and saf...

Several tests based on chemiluminescence immunoassay techniques have become available to test for SARS-CoV-2 antibodies. There is currently insufficient data on serology assay performance beyond 35 days after symptoms onset. We aimed to evaluate SARS-CoV-2 antibody tests on three widely used platforms. A chemiluminescent microparticle immunoassay (...

The HIV-1 reservoir is the major hurdle to curing HIV-1. However, the impact of the viral genome on the HIV-1 reservoir, i.e. its heritability, remains unknown. We investigate the heritability of the HIV-1 reservoir size and its long-term decay by analyzing the distribution of those traits on viral phylogenies from both partial-pol and viral near f...

HIV-1 genetic diversity can be used to infer time since infection (TSI) and infection recency. We adapted this approach for HCV and identified genomic regions with informative diversity. We included 72 HCV/HIV-1 coinfected participants of the Swiss HIV Cohort Study, for whom reliable estimates of infection date and viral sequences were available. A...

Background Integrase strand transfer inhibitors (InSTIs) are recommended for first-line treatment of HIV-infection. We identified risk factors, including baseline minor InSTI resistance mutations, for treatment failure of InSTI-based regimens. Methods We studied time to treatment failure and time to viral suppression among 1419 drug-naive patients...

Knowledge of the sensitivities of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) antibody tests beyond 35 days after the clinical onset of COVID-19 is insufficient. We aimed to describe positivity rate of SARS-CoV-2 assays employing three different measurement principles over a prolonged period. Two hundred sixty-eight samples from 18...

In this prospective cohort of 1'012 Swiss hospital employees, three different assays were used to screen serum for SARS-CoV-2 antibodies. Seropositivity was 1%; the positive predictive value of the lateral-flow immunoassay was 64% (IgG) and 13% (IgM). History of fever and myalgia most effectively differentiated seropositive and seronegative partici...

Background Identifying local outbreaks and their drivers is a key step towards curbing HIV transmission and potentially achieving HIV elimination. Such outbreaks can be identified as transmission clusters extracted from phylogenetic trees constructed of densely sampled viral sequences. In this study, we combined phylogenetic transmission clusters w...

Objective There is limited data on abdominal obesity and the influence of genetics on weight change after antiretroviral therapy (ART) initiation. We assessed body mass index (BMI) and waist hip ration (WHR) change over time in the Swiss HIV Cohort study (SHCS). Methods Mixed-effects models characterizing BMI and WHR change over time in 1090 SHCS...

Background Syphilis is re-emerging globally in general and HIV-infected populations and repeated syphilis episodes may play a central role in syphilis transmission among core groups. Besides sexual behavioural factors, little is known about determinants of repeated syphilis episodes in HIV-infected individuals ─ including the potential impact of pr...

INTRODUCTION In many countries, mortality due to suicide is higher among people living with HIV than in the general population. We aimed to analyse trends in suicide mortality before and after the introduction of triple combination antiretroviral therapy (cART), and to identify risk factors associated with death from suicide in Switzerland. METHODS...

Introduction: In many countries, mortality due to suicide is higher among people living with HIV than in the general population. We aimed to analyse trends in suicide mortality before and after the introduction of triple combination antiretroviral therapy (cART), and to identify risk factors associated with death from suicide in Switzerland. Meth...

Background: The level of evidence for HIV transmission risk through condomless sex in serodifferent gay couples with the HIV-positive partner taking virally suppressive antiretroviral therapy (ART) is limited compared with the evidence available for transmission risk in heterosexual couples. The aim of the second phase of the PARTNER study (PARTNE...

Aims of the study: Nevirapine has an exceptional record for long-term tolerability with few side effects in human immunodeficiency virus (HIV) combined antiretroviral therapy (cART). Owing to relatively frequent hypersensitivity reactions (HSR) (15–25%) in the first 3 months after treatment initiation (especially in patients with a high CD4 count...

Background: Nucleoside (or nucleotide) reverse transcriptase inhibitors (NRTIs) cause side effects in some patients, prompting the use of either partly or fully NRTI-sparing regimens. Methods: We used data from the Swiss HIV Cohort Study to estimate the effectiveness of two new dolutegravir dual regimens relative to the alternative NRTI-sparing...

Background: In Switzerland, since 5/2017, intravenous drug users and since 10/2017, all patients with chronic hepatitis C can be treated with direct-acting antivirals (DAA) irrespective of liver fibrosis grade. Since 2018, a study within the Swiss Association for the Medical Management in Substance Users (SAMMSU)-cohort evaluates the benefit of HC...

Background: HIV's capacity to escape immune recognition by Human Leukocyte Antigen (HLA) is a core component of HIV pathogenesis. A better understanding of the distribution of HLA Class I in HIV-infected patients would improve our knowledge of pathogenesis in relation to host HLA type, and could better improve therapeutic strategies against HIV....

Background: HIV-1 genetic diversity increases over the course of infection, and can be used to infer time since infection (TSI) and consequently also infection recency, crucial quantities for HIV-1 surveillance and the understanding of viral pathogenesis. Methods: We considered 313 HIV-infected individuals for whom reliable estimates of infectio...

BACKGROUND AND AIMS: Direct-acting antiviral agents have revolutionised hepatitis C treatment. In 2014, the Swiss Hepatitis Strategy was developed to eliminate hepatitis C virus (HCV) infection and the associated liver-related morbidity and mortality by 2030. Though numerous national studies and assessments have identified a relatively low prevalen...

2019 Swiss Recommendations on the prevention of HIV mother-to-child transmission developed by an ad hoc group of members of the Swiss Mother and Child HIV Cohort Study (MoCHiV) and approved by the Swiss Federal Commission of Sexual Health. It was published in a translated German and French version in the FOPH (Federal Office of Public Health Switze...

NEVIRAPINE PLUS LAMIVUDINE TO MAINTAIN HIV SUPPRESSION THROUGH WEEK 4

Combined antiretroviral treatment (cART) has reduced mother-to-child transmission (MTCT) of the human immunodeficiency virus (HIV) to virtually zero in industrialised countries, where strictly bottle feeding is recommended for HIV-infected mothers, and to as low as 0.7% after 12 months in low-resource settings, where breastfeeding is strongly encou...

Background Human immunodeficiency virus (HIV) transmission among injecting drug users (IDUs) is increasing in the United States due to the recent opioid epidemic and is the leading mode of transmission in Eastern Europe. Methods To evaluate the overall impact of HIV harm reduction, we combined (1) data from the Swiss HIV Cohort Study and public so...

Objective: To compare the frequency and risk factors of toxicity-related treatment discontinuations between raltegravir and dolutegravir. Design: Prospective cohort study. Methods: All antiretroviral treatment (ART)-naïve and ART-experienced HIV-infected individuals from the Swiss HIV Cohort Study who initiated raltegravir or dolutegravir betw...

Vaccination against complex pathogens such as typhoidal and non-typhoidal Salmonella requires the concerted action of different immune effector mechanisms. Outer membrane proteins (Omps) of Salmonella Typhi are potent immunogens, which elicit long-lasting and protective immunity. Here, we followed the evolution of S. Typhi OmpC and F-specific T and...

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Identification of CD38+ antibody secreting cells in peripheral blood following Ty21a vaccination. PBMCs were collected from vaccinated or control (Ctrl) subjects at the indicated time points and analysis of different B cell populations was performed by flow cytometry. (A) Gating strategy for FACS analysis of IgD- CD38- B cells (blue) or CD38+ antib...

Background Significance and clinical utility of multiple virus detection by multiplex real-time polymerase chain reaction (rtPCR) in respiratory tract infection remain unclear. Methods This retrospective cohort study analyzed how virus detection affected clinical management. During a 27-month period, clinical and laboratory information was collecte...

Supporting Information

Objectives: To estimate life expectancy (LE) over 25 years in HIV-positive people and compare their LE with recent estimates for the general population, by education. Methods: Patients aged 20 years or older enrolled in the Swiss HIV Cohort Study 1988-2013 were eligible. Patients alive in 2001 were matched to up to 100 Swiss residents, by sex, y...

Background In 2014, the Joint United Nations Programme on HIV and AIDS (UNAIDS) and partners set the ‘90-90-90 targets’; aiming to diagnose 90% of all HIV positive people, provide antiretroviral therapy (ART) for 90% of those diagnosed and achieve viral suppression for 90% of those treated, by 2020. This results in 81% of all HIV positive people on...

Conclusion: Treatment interventions to curb the HCV epidemic among HIV-infected MSM are effective if high-risk behavior does not increase as it has during the last decade. Reducing high-risk behavior associated with HCV transmission would be the most effective intervention for controlling the HCV epidemic, even if this was not accompanied by an in...

Importance: A key factor in assessing the effectiveness and cost-effectiveness of antiretroviral therapy (ART) as a prevention strategy is the absolute risk of HIV transmission through condomless sex with suppressed HIV-1 RNA viral load for both anal and vaginal sex. Objective: To evaluate the rate of within-couple HIV transmission (heterosexual...