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1. Association of institutional masking policies with healthcare-associated SARS-CoV-2 infections in Swiss acute care hospitals during the BA.4/5 wave (CH-SUR study): a retrospective observational study

Author

Dörr, Tamara, Güsewell, Sabine, Flury, Domenica, Süveges, Maria, Gaza Valera, Camille Beatrice, Botero-Mesa, Sara, Zanella, Marie-Céline, Iten, Anne, Balmelli, Carlo, Troillet, Nicolas, Tschudin-Sutter, Sarah, W Schreiber, Peter, Jent, Philipp, Damonti, Lauro, Sommerstein, Rami, Portmann, Lea, Vuichard-Gysin, Danielle, Cusini, Alexia, Nussbaumer-Ochsner, Yvonne, Heininger, Ulrich, Berger, Christoph, Zimmermann, Petra, Gardiol, Céline, Keiser, Olivia, Schlegel, Matthias, Kohler, Philipp, and P Kuster, Stefan

Published
2024
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4. Viral suppression and retention in HIV care during the postpartum period among women living with HIV: a longitudinal multicenter cohort study

Author

Abela, I., Aebi-Popp, K., Anagnostopoulos, A., Battegay, M., Baumann, M., Bernasconi, E., Braun, D.L., Bucher, H.C., Calmy, A., Cavassini, M., Ciuffi, A., Crisinel, P.A., Darling, K., Duppenthaler, A., Dollenmaier, G., Egger, M., Elzi, L., Fehr, J., Fellay, J., Francini, K., Furrer, H., Fux, C.A., Günthard, H.F., Hachfeld, A., Haerry, D., Hasse, B., Hirsch, H.H., Hoffmann, M., Hösli, I., Huber, M., Jackson-Perry, D., Kahlert, C.R., Kaiser, L., Kapfhammer, E., Keiser, O., Klimkait, T., Kohns, M., Kottanattu, L., Kouyos, R.D., Kovari, H., Kusejko, K., Labhardt, N., Martinez de Tejada, B., Marzolini, C., Metzner, K.J., Müller, N., Nemeth, J., Nicca, D., Notter, J., Paioni, P., Pantaleo, G., Perreau, M., Polli, Ch, Rauch, A., Salazar-Vizcaya, L., Schmid, P., Speck, R., Stöckle, M., Tarr, P., Thanh Lecompte, M., Trkola, A., Wagner, N., Wandeler, G., Weisser, M., Yerly, S., Paioni, Paolo, Aebi-Popp, Karoline, Martinez de Tejada, Begoña, Rudin, Christoph, Bernasconi, Enos, Braun, Dominique L., Kouyos, Roger, Wagner, Noémie, Crisinel, Pierre Alex, Güsewell, Sabine, Darling, Katharine E.A., Duppenthaler, Andrea, Baumann, Marc, Polli, Christian, Fischer, Tina, and Kahlert, Christian R.

Published
2023
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7. Impact of respirator versus surgical masks on SARS-CoV-2 acquisition in healthcare workers: a prospective multicentre cohort

Author

Haller, Sabine, Güsewell, Sabine, Egger, Thomas, Scanferla, Giulia, Thoma, Reto, Leal-Neto, Onicio B., Flury, Domenica, Brucher, Angela, Lemmenmeier, Eva, Möller, J. Carsten, Rieder, Philip, Rütti, Markus, Stocker, Reto, Vuichard-Gysin, Danielle, Wiggli, Benedikt, Besold, Ulrike, Kuster, Stefan P., McGeer, Allison, Risch, Lorenz, Schlegel, Matthias, Friedl, Andrée, Vernazza, Pietro, Kahlert, Christian R., and Kohler, Philipp

Published
2022
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8. Non-occupational and occupational factors associated with specific SARS-CoV-2 antibodies among hospital workers – A multicentre cross-sectional study

Author

Kahlert, Christian R., Persi, Raphael, Güsewell, Sabine, Egger, Thomas, Leal-Neto, Onicio B., Sumer, Johannes, Flury, Domenica, Brucher, Angela, Lemmenmeier, Eva, Möller, J. Carsten, Rieder, Philip, Stocker, Reto, Vuichard-Gysin, Danielle, Wiggli, Benedikt, Albrich, Werner C., Babouee Flury, Baharak, Besold, Ulrike, Fehr, Jan, Kuster, Stefan P., McGeer, Allison, Risch, Lorenz, Schlegel, Matthias, Friedl, Andrée, Vernazza, Pietro, and Kohler, Philipp

Published
2021
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12. SARS‐CoV‐2 Vaccination is Not Associated With Involuntary Childlessness in Female Healthcare Workers: A Multicenter Cohort Study.

Author

Dörr, Tamara, Güsewell, Sabine, Cusini, Alexia, Brucher, Angela, Goppel, Stephan, Grässli, Fabian, Betschon, Elsbeth, Möller, J. Carsten, Ortner, Manuela, Ruetti, Markus, Stocker, Reto, Vuichard‐Gysin, Danielle, Besold, Ulrike, Risch, Lorenz, von Kietzell, Matthias, Schlegel, Matthias, Kuster, Stefan P., Kahlert, Christian R., and Kohler, Philipp

Subjects
*MEDICAL personnel, *SARS-CoV-2, *VACCINE hesitancy, *INFERTILITY, *VACCINATION, *COHORT analysis
Abstract

Background: There is debate about the causes of the recent birth rate decline in high‐income countries worldwide. During the pandemic, concern about the effects on reproductive health has caused vaccine hesitancy. We investigated the association of SARS‐CoV‐2 vaccination and infection with involuntary childlessness. Methods: Females in fertility age within a prospective multicenter cohort of healthcare workers (HCW) were followed since August 2020. Data on baseline health, SARS‐CoV‐2‐infection, and vaccination were obtained and regularly updated, in which serum samples were collected repetitively and screened for anti‐nucleocapsid and anti‐spike antibodies. In October 2023, participants indicated the presence of involuntary childlessness with onset during the pandemic, whereas those indicating an onset before the pandemic were excluded. The association of involuntary childlessness and SARS‐CoV‐2‐vaccination and infection was investigated using univariable and multivariable analysis. Sensitivity analysis was performed to compare those reporting involuntary childlessness with those birthing a child since 2020. Results: Of 798 participants, 26 (3.2%) reported involuntary childlessness starting since the pandemic. Of the involuntary childless women, 73.1% (19/26) were vaccinated compared to 86.0% (664/772) without involuntary childlessness (p = 0.73). SARS‐CoV‐2 infection was reported by 76.9% (20/26) compared to 72.4% (559/772) of controls (p = 0.64). Neither SARS‐CoV‐2 vaccination (aOR 0.91 per dose, 95%CI 0.67–1.26) nor infection (aOR per infection 1.05, 95%CI 0.62–1.71) was associated with involuntary childlessness. Sensitivity analysis confirmed these results. Conclusions: Among female HCW of fertility age, 3.2% indicated involuntary childlessness, which is comparable to pre‐pandemic data. No association between involuntary childlessness and SARS‐CoV‐2 vaccination or infection was found. [ABSTRACT FROM AUTHOR]

Published
2024
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14. Impact of baseline SARS-CoV-2 antibody status on syndromic surveillance and the risk of subsequent COVID-19—a prospective multicenter cohort study

Author

Kohler, Philipp, Güsewell, Sabine, Seneghini, Marco, Egger, Thomas, Leal, Onicio, Brucher, Angela, Lemmenmeier, Eva, Möller, J. Carsten, Rieder, Philip, Ruetti, Markus, Stocker, Reto, Vuichard-Gysin, Danielle, Wiggli, Benedikt, Besold, Ulrike, Kuster, Stefan P., McGeer, Allison, Risch, Lorenz, Friedl, Andrée, Schlegel, Matthias, Vernazza, Pietro, and Kahlert, Christian R.

Published
2021
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18. Viral suppression and retention in HIV care during the postpartum period among women living with HIV: a longitudinal multicenter cohort study

Author

Paioni, Paolo, primary, Aebi-Popp, Karoline, additional, Martinez de Tejada, Begoña, additional, Rudin, Christoph, additional, Bernasconi, Enos, additional, Braun, Dominique L., additional, Kouyos, Roger, additional, Wagner, Noémie, additional, Crisinel, Pierre Alex, additional, Güsewell, Sabine, additional, Darling, Katharine E.A., additional, Duppenthaler, Andrea, additional, Baumann, Marc, additional, Polli, Christian, additional, Fischer, Tina, additional, Kahlert, Christian R., additional, Abela, I., additional, Aebi-Popp, K., additional, Anagnostopoulos, A., additional, Battegay, M., additional, Baumann, M., additional, Bernasconi, E., additional, Braun, D.L., additional, Bucher, H.C., additional, Calmy, A., additional, Cavassini, M., additional, Ciuffi, A., additional, Crisinel, P.A., additional, Darling, K., additional, Duppenthaler, A., additional, Dollenmaier, G., additional, Egger, M., additional, Elzi, L., additional, Fehr, J., additional, Fellay, J., additional, Francini, K., additional, Furrer, H., additional, Fux, C.A., additional, Günthard, H.F., additional, Hachfeld, A., additional, Haerry, D., additional, Hasse, B., additional, Hirsch, H.H., additional, Hoffmann, M., additional, Hösli, I., additional, Huber, M., additional, Jackson-Perry, D., additional, Kahlert, C.R., additional, Kaiser, L., additional, Kapfhammer, E., additional, Keiser, O., additional, Klimkait, T., additional, Kohns, M., additional, Kottanattu, L., additional, Kouyos, R.D., additional, Kovari, H., additional, Kusejko, K., additional, Labhardt, N., additional, Martinez de Tejada, B., additional, Marzolini, C., additional, Metzner, K.J., additional, Müller, N., additional, Nemeth, J., additional, Nicca, D., additional, Notter, J., additional, Paioni, P., additional, Pantaleo, G., additional, Perreau, M., additional, Polli, Ch, additional, Rauch, A., additional, Salazar-Vizcaya, L., additional, Schmid, P., additional, Speck, R., additional, Stöckle, M., additional, Tarr, P., additional, Thanh Lecompte, M., additional, Trkola, A., additional, Wagner, N., additional, Wandeler, G., additional, Weisser, M., additional, and Yerly, S., additional

Published
2023
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20. Viral suppression and retention in HIV care during the postpartum period among women living with HIV: a longitudinal multicenter cohort study

Author

Paioni, Paolo, Aebi-Popp, Karoline, Martinez de Tejada, Begoña, Rudin, Christoph, Bernasconi, Enos, Braun, Dominique L, Kouyos, Roger, Wagner, Noémie, Crisinel, Pierre Alex, Güsewell, Sabine, Darling, Katharine E A, Duppenthaler, Andrea, Baumann, Marc, Polli, Christian, Fischer, Tina, and Kahlert, Christian R

Subjects
610 Medicine & health
Abstract

BACKGROUND Low rates of postnatal retention in HIV care and viral suppression have been reported in women living with HIV (WLWH) despite viral suppression at delivery. At the same time, postpartum follow-up is of crucial importance in light of the increasing support offered in many resource-rich countries including Switzerland to WLWH choosing to breastfeed their infant, if optimal scenario criteria are met. METHODS We longitudinally investigated retention in HIV care, viral suppression, and infant follow-up in a prospective multicentre HIV cohort study of WLWH in the optimal scenario who had a live birth between January 2000 and December 2018. Risk factors for adverse outcomes in the first year postpartum were assessed using logistic and proportional hazard models. FINDINGS Overall, WLWH were retained in HIV care for at least six months after 94.2% of the deliveries (694/737). Late start of combination antiretroviral therapy (cART) during the third trimester was found to be the main risk factor for failure of retention in HIV care (crude odds ratio [OR] 3.91; 95% confidence interval [CI], 1.50-10.22; p = 0.005). Among mothers on cART until at least one year after delivery, 4.4% (26/591) experienced viral failure, with illicit drugs use being the most important risk factor (hazard ratio [HR], 13.2; 95% CI, 2.35-73.6; p = 0.003). The main risk factors for not following the recommendations regarding infant follow-up was maternal depression (OR, 3.52; 95% CI, 1.18-10.52; p = 0.024). INTERPRETATION Although the results are reassuring, several modifiable risk factors for adverse postpartum outcome, such as late treatment initiation and depression, were identified. These factors should be addressed in HIV care of all WLWH, especially those opting to breastfeed in resource-rich countries. FUNDING This study has been financed within the framework of the Swiss HIV Cohort Study, supported by the Swiss National Science Foundation (grant #201369), by SHCS project 850 and by the SHCS research foundation.

Published
2023

31. Clinical symptoms of SARS-CoV-2 breakthrough infection during the Omicron period in relation to baseline immune status and booster vaccination-A prospective multicentre cohort of health professionals (SURPRISE study)

Author

Kohler, Philipp, Babouee Flury, Baharak, Güsewell, Sabine, Egger, Thomas, Leal, Onicio, Brucher, Angela, Lemmenmeier, Eva, Meier Kleeb, Dorette, Möller, J Carsten, Ortner, Manuela, Rieder, Philip, Ruetti, Markus, Schmid, Hans-Ruedi, Stocker, Reto, Vuichard-Gysin, Danielle, Speer, Oliver, Wiggli, Benedikt, Besold, Ulrike, McGeer, Allison, Risch, Lorenz, Friedl, Andrée, Schlegel, Matthias, Vernazza, Pietro, Kahlert, Christian R, and Kuster, Stefan P

Subjects
610 Medicine & health
Abstract

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 compared to vaccination only. Moreover, the frequencies of dizziness, cough and muscle or limb pain were lower in participants who had received a booster vaccine dose. Thus, hybrid immunity appeared to be superior in preventing specific symptoms during breakthrough infection compared to vaccination alone. A booster vaccine dose conferred additional symptom reduction.

Published
2023

33. Viral suppression and retention in HIV care during the postpartum period among women living with HIV: a longitudinal multicenter cohort study

Author

Paioni, Paolo; https://orcid.org/0000-0002-3904-1606, Aebi-Popp, Karoline; https://orcid.org/0000-0002-9337-900X, Martinez de Tejada, Begoña, Rudin, Christoph, Bernasconi, Enos; https://orcid.org/0000-0002-9724-8373, Braun, Dominique L; https://orcid.org/0000-0003-4036-1030, Kouyos, Roger; https://orcid.org/0000-0002-9220-8348, Wagner, Noémie; https://orcid.org/0000-0001-9133-9752, Crisinel, Pierre Alex; https://orcid.org/0000-0002-1967-8255, Güsewell, Sabine; https://orcid.org/0000-0001-8442-8888, Darling, Katharine E A; https://orcid.org/0000-0003-1449-3873, Duppenthaler, Andrea, Baumann, Marc, Polli, Christian, Fischer, Tina, Kahlert, Christian R; https://orcid.org/0000-0002-0784-3276, Swiss HIV Cohort Study (SHCS) and the Swiss Mother and Child HIV, Paioni, Paolo; https://orcid.org/0000-0002-3904-1606, Aebi-Popp, Karoline; https://orcid.org/0000-0002-9337-900X, Martinez de Tejada, Begoña, Rudin, Christoph, Bernasconi, Enos; https://orcid.org/0000-0002-9724-8373, Braun, Dominique L; https://orcid.org/0000-0003-4036-1030, Kouyos, Roger; https://orcid.org/0000-0002-9220-8348, Wagner, Noémie; https://orcid.org/0000-0001-9133-9752, Crisinel, Pierre Alex; https://orcid.org/0000-0002-1967-8255, Güsewell, Sabine; https://orcid.org/0000-0001-8442-8888, Darling, Katharine E A; https://orcid.org/0000-0003-1449-3873, Duppenthaler, Andrea, Baumann, Marc, Polli, Christian, Fischer, Tina, Kahlert, Christian R; https://orcid.org/0000-0002-0784-3276, and Swiss HIV Cohort Study (SHCS) and the Swiss Mother and Child HIV

Abstract

BACKGROUND: Low rates of postnatal retention in HIV care and viral suppression have been reported in women living with HIV (WLWH) despite viral suppression at delivery. At the same time, postpartum follow-up is of crucial importance in light of the increasing support offered in many resource-rich countries including Switzerland to WLWH choosing to breastfeed their infant, if optimal scenario criteria are met. METHODS: We longitudinally investigated retention in HIV care, viral suppression, and infant follow-up in a prospective multicentre HIV cohort study of WLWH in the optimal scenario who had a live birth between January 2000 and December 2018. Risk factors for adverse outcomes in the first year postpartum were assessed using logistic and proportional hazard models. FINDINGS: Overall, WLWH were retained in HIV care for at least six months after 94.2% of the deliveries (694/737). Late start of combination antiretroviral therapy (cART) during the third trimester was found to be the main risk factor for failure of retention in HIV care (crude odds ratio [OR] 3.91; 95% confidence interval [CI], 1.50-10.22; p = 0.005). Among mothers on cART until at least one year after delivery, 4.4% (26/591) experienced viral failure, with illicit drugs use being the most important risk factor (hazard ratio [HR], 13.2; 95% CI, 2.35-73.6; p = 0.003). The main risk factors for not following the recommendations regarding infant follow-up was maternal depression (OR, 3.52; 95% CI, 1.18-10.52; p = 0.024). INTERPRETATION: Although the results are reassuring, several modifiable risk factors for adverse postpartum outcome, such as late treatment initiation and depression, were identified. These factors should be addressed in HIV care of all WLWH, especially those opting to breastfeed in resource-rich countries. FUNDING: This study has been financed within the framework of the Swiss HIV Cohort Study, supported by the Swiss National Science Foundation (grant #201369), by SHCS project 850 and b

Published
2023

34. Antibodies as biomarker candidates for response and survival to checkpoint inhibitors in melanoma patients

Author

Fässler, Mirjam, Diem, Stefan, Mangana, Joanna, Hasan Ali, Omar, Berner, Fiamma, Bomze, David, Ring, Sandra, Niederer, Rebekka, del Carmen Gil Cruz, Cristina, Pérez Shibayama, Christian Ivan, Krolik, Michal, Siano, Marco, Joerger, Markus, Recher, Mike, Risch, Lorenz, Güsewell, Sabine, Risch, Martin, Speiser, Daniel E., Ludewig, Burkhard, Levesque, Mitchell P., Dummer, Reinhard, and Flatz, Lukas

Published
2019
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35. Post-acute sequelae after SARS-CoV-2 infection by viral variant and vaccination status: a multicenter cross-sectional study

Author

Kahlert, Christian R, Strahm, Carol, Güsewell, Sabine, Cusini, Alexia, Brucher, Angela, Goppel, Stephan, Möller, Elisabeth, Möller, J Carsten, Ortner, Manuela, Ruetti, Markus, Stocker, Reto, Vuichard-Gysin, Danielle, Besold, Ulrike, McGeer, Allison, Risch, Lorenz, Friedl, Andrée, Schlegel, Matthias, Vernazza, Pietro, Kuster, Stefan P, and Kohler, Philipp

Subjects
610 Medicine & health
Abstract

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 Switzerland. HCW were stratified by viral variant and vaccination status at time of their first positive SARS-CoV-2 nasopharyngeal swab. HCW without positive swab and with negative serology served as controls. The sum of eighteen self-reported PASC symptoms was modeled with univariable and multivariable negative-binomial regression to analyse the association of mean symptom number with viral variant and vaccination status. RESULTS Among 2'912 participants (median age 44 years, 81.3% female), PASC symptoms were significantly more frequent after wild-type infection (estimated mean symptom number 1.12, p

Published
2023
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38. Post-Acute Sequelae After Severe Acute Respiratory Syndrome Coronavirus 2 Infection by Viral Variant and Vaccination Status: A Multicenter Cross-Sectional Study.

Author

Kahlert, Christian R, Strahm, Carol, Güsewell, Sabine, Cusini, Alexia, Brucher, Angela, Goppel, Stephan, Möller, Elisabeth, Möller, J Carsten, Ortner, Manuela, Ruetti, Markus, Stocker, Reto, Vuichard-Gysin, Danielle, Besold, Ulrike, McGeer, Allison, Risch, Lorenz, Friedl, Andrée, Schlegel, Matthias, Vernazza, Pietro, Kuster, Stefan P, and Kohler, Philipp

Subjects
RESEARCH, COVID-19, CONFIDENCE intervals, POST-acute COVID-19 syndrome, SICK people, COVID-19 vaccines, CROSS-sectional method, SELF-evaluation, MEDICAL personnel, REGRESSION analysis, VACCINE effectiveness, RISK assessment, RESEARCH funding, DESCRIPTIVE statistics, VACCINATION status, ODDS ratio, LONGITUDINAL method, DISEASE risk factors, SYMPTOMS, EVALUATION
Abstract

Background Disentangling the effects of severe acute respiratory syndrome coronavirus 2 (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 Switzerland. HCWs were stratified by viral variant and vaccination status at time of their first positive SARS-CoV-2 nasopharyngeal swab. HCWs without positive swab and with negative serology served as controls. The sum of 18 self-reported PASC symptoms was modeled with univariable and multivariable negative-binomial regression to analyze the association of mean symptom number with viral variant and vaccination status. Results Among 2912 participants (median age: 44 years; 81.3% female), PASC symptoms were significantly more frequent after wild-type infection (estimated mean symptom number: 1.12; P <.001; median time since infection: 18.3 months), after Alpha/Delta infection (0.67 symptoms; P <.001; 6.5 months), and after Omicron BA.1 infections (0.52 symptoms; P =.005; 3.1 months) versus uninfected controls (0.39 symptoms). After Omicron BA.1 infection, the estimated mean symptom number was 0.36 for unvaccinated individuals versus 0.71 with 1–2 vaccinations (P =.028) and 0.49 with ≥3 prior vaccinations (P =.30). Adjusting for confounders, only wild-type (adjusted rate ratio [aRR]: 2.81; 95% confidence interval [CI]: 2.08–3.83) and Alpha/Delta infections (aRR: 1.93; 95% CI: 1.10–3.46) were significantly associated with the outcome. Conclusions Previous infection with pre-Omicron variants was the strongest risk factor for PASC symptoms among our HCWs. Vaccination before Omicron BA.1 infection was not associated with a clear protective effect against PASC symptoms in this population. [ABSTRACT FROM AUTHOR]

Published
2023
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39. Risk and symptoms of COVID-19 in health professionals according to baseline immune status and booster vaccination during the Delta and Omicron waves in Switzerland-A multicentre cohort study

Author

Babouee Flury, Baharak, Güsewell, Sabine, Egger, Thomas, Leal, Onicio, Brucher, Angela, Lemmenmeier, Eva, Meier Kleeb, Dorette, Möller, J Carsten, Rieder, Philip, Rütti, Markus, Schmid, Hans-Ruedi, Stocker, Reto, Vuichard-Gysin, Danielle, Wiggli, Benedikt, Besold, Ulrike, McGeer, Allison, Risch, Lorenz, Friedl, Andrée, Schlegel, Matthias, Kuster, Stefan P, Kahlert, Christian R, and Kohler, Philipp

Subjects
SARS-CoV-2, Vaccination, Humans, COVID-19, 610 Medicine & health, Viral Vaccines, Prospective Studies, 610 Medizin und Gesundheit, Switzerland
Abstract

BACKGROUND Knowledge about protection conferred by previous Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection and/or vaccination against emerging viral variants allows clinicians, epidemiologists, and health authorities to predict and reduce the future Coronavirus Disease 2019 (COVID-19) burden. We investigated the risk and symptoms of SARS-CoV-2 (re)infection and vaccine breakthrough infection during the Delta and Omicron waves, depending on baseline immune status and subsequent vaccinations. METHODS AND FINDINGS In this prospective, multicentre cohort performed between August 2020 and March 2022, we recruited hospital employees from ten acute/nonacute healthcare networks in Eastern/Northern Switzerland. We determined immune status in September 2021 based on serology and previous SARS-CoV-2 infections/vaccinations: Group N (no immunity); Group V (twice vaccinated, uninfected); Group I (infected, unvaccinated); Group H (hybrid: infected and ≥1 vaccination). Date and symptoms of (re)infections and subsequent (booster) vaccinations were recorded until March 2022. We compared the time to positive SARS-CoV-2 swab and number of symptoms according to immune status, viral variant (i.e., Delta-dominant before December 27, 2021; Omicron-dominant on/after this date), and subsequent vaccinations, adjusting for exposure/behavior variables. Among 2,595 participants (median follow-up 171 days), we observed 764 (29%) (re)infections, thereof 591 during the Omicron period. Compared to group N, the hazard ratio (HR) for (re)infection was 0.33 (95% confidence interval [CI] 0.22 to 0.50, p < 0.001) for V, 0.25 (95% CI 0.11 to 0.57, p = 0.001) for I, and 0.04 (95% CI 0.02 to 0.10, p < 0.001) for H in the Delta period. HRs substantially increased during the Omicron period for all groups; in multivariable analyses, only belonging to group H was associated with protection (adjusted HR [aHR] 0.52, 95% CI 0.35 to 0.77, p = 0.001); booster vaccination was associated with reduction of breakthrough infection risk in groups V (aHR 0.68, 95% CI 0.54 to 0.85, p = 0.001) and H (aHR 0.67, 95% CI 0.45 to 1.00, p = 0.048), largely observed in the early Omicron period. Group H (versus N, risk ratio (RR) 0.80, 95% CI 0.66 to 0.97, p = 0.021) and participants with booster vaccination (versus nonboosted, RR 0.79, 95% CI 0.71 to 0.88, p < 0.001) reported less symptoms during infection. Important limitations are that SARS-CoV-2 swab results were self-reported and that results on viral variants were inferred from the predominating strain circulating in the community at that time, rather than sequencing. CONCLUSIONS Our data suggest that hybrid immunity and booster vaccination are associated with a reduced risk and reduced symptom number of SARS-CoV-2 infection during Delta- and Omicron-dominant periods. For previously noninfected individuals, booster vaccination might reduce the risk of symptomatic Omicron infection, although this benefit seems to wane over time.

Published
2022

42. Short tau inversion recovery (STIR) after intravenous contrast agent administration obscures bone marrow edema-like signal on forefoot MRI

Author

Fischer, Tim; https://orcid.org/0000-0002-1807-9146, Baz, Yassir El, Waelti, Stephan; https://orcid.org/0000-0003-4175-0476, Wildermuth, Simon; https://orcid.org/0000-0002-3278-4335, Leschka, Sebastian; https://orcid.org/0000-0002-7973-0203, Güsewell, Sabine; https://orcid.org/0000-0001-8442-8888, Dietrich, Tobias Johannes; https://orcid.org/0000-0003-2979-6471, Fischer, Tim; https://orcid.org/0000-0002-1807-9146, Baz, Yassir El, Waelti, Stephan; https://orcid.org/0000-0003-4175-0476, Wildermuth, Simon; https://orcid.org/0000-0002-3278-4335, Leschka, Sebastian; https://orcid.org/0000-0002-7973-0203, Güsewell, Sabine; https://orcid.org/0000-0001-8442-8888, and Dietrich, Tobias Johannes; https://orcid.org/0000-0003-2979-6471

Abstract

Objective: Short tau or short TI inversion recovery (STIR) MRI sequences are considered a robust fat suppression technique. However, STIR also suppresses signals from other tissues with similar T1 relaxation times. This study investigates the in vivo effect of intravenous gadolinium-based T1-shortening contrast agent on STIR signal. Materials and methods: Institutional board approval and informed consent was obtained. MRI examinations (1.5-T or 3-T) of 31 prospectively included patients were analyzed by two readers. Signal intensity of degenerative bone marrow edema-like signal at the Lisfranc joint on precontrast STIR images and on STIR images acquired after intravenous contrast agent administration (gadoteric acid, gadolinium: 0.5 mmol/ml, 15 ml) was measured. The medial cuneiform bone without observable bone marrow edema-like signal was considered a healthy tissue and served as a reference. Relative changes in signal intensity between precontrast and postcontrast images were calculated for the two tissues. Wilcoxon signed-rank test served for statistical analyses. Results: In bone marrow edema-like signal, both readers observed a median signal change of -35% (interquartile range (IQR) 24) and -34% (IQR 21), respectively, on postcontrast STIR images compared to precontrast STIR. In healthy tissue, the signal remained constant on postcontrast STIR images (median change -2%, IQR 15, and 0%, IQR 17) respectively. For both readers, postcontrast signal change in bone marrow edema-like signal differed from that in healthy tissue (p < 0.001). Conclusion: Intravenous gadolinium-based contrast agent causes a significant reduction of signal intensity in bone marrow edema-like signal on routine STIR images. Thus, pathological MRI findings may be obscured. Keywords: Bone marrow edema-like signal; Contrast media; Foot; Magnetic resonance imaging

Published
2022

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