Léo Pomar

Prof. Dr. Léo Pomar

Materno-fetal and Obstetrics Research Unit, Department Woman-Mother-Child, Lausanne University Hospital, Switzerland
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Research Focus & Metrics

Academic Career Length

10Years (2017-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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Michael CeulemansMichael Ceulemans
Michael Ceulemans
VFVeerle Foulon
Veerle Foulon
Alice PanchaudAlice Panchaud
Alice Panchaud
UWUrsula Winterfeld
Ursula Winterfeld
LPLéo Pomar
Léo Pomar
HNHedvig Nordeng
Hedvig Nordeng
The COVID-19 pandemic may be of particular concern for pregnant and breastfeeding women. We aimed to explore their beliefs about the coronavirus and COVID-19 vaccine willingness and to assess the impact of the pandemic on perinatal experiences and practices. A multinational, cross-sectional, web-based study was performed in six European countries between April and July 2020. The anonymous survey was promoted via social media. In total, 16,063 women participated (including 6661 pregnant and 9402 breastfeeding women). Most responses were collected from Belgium (44%), Norway (18%) and the Netherlands (16%), followed by Switzerland (11%), Ireland (10%) and the UK (3%). Despite differences between countries, COVID-19 vaccine hesitancy was identified among 40–50% of the respondents at the end of the first wave of the pandemic and was higher among pregnant women. Education level and employment status were associated with vaccine hesitancy. The first wave had an adverse impact on pregnancy experiences and disrupted access to health services and breastfeeding support for many women. In the future, access to health care and support should be maintained at all times. Evidence-based and tailored information on COVID-19 vaccines should also be provided to pregnant and breastfeeding women to avoid unfounded concerns about the vaccines and to support shared decision making in this population.

28 October 2020 in Pathogens
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SMSophie Masmejan
Sophie Masmejan
DMdidier musso
didier musso
MVManon Vouga
Manon Vouga
LPLéo Pomar
Léo Pomar
PDPradip Dashraath
Pradip Dashraath
DBDavid Baud
David Baud
Zika virus (ZIKV), a neurotropic single-stranded RNA flavivirus, remains an important cause of congenital infection, fetal microcephaly, and Guillain-Barré syndrome in populations where ZIKV has adapted to a nexus involving the Aedes mosquitoes and humans. To date, outbreaks of ZIKV have occurred in Africa, Southeast Asia, the Pacific islands, the Americas, and the Caribbean. Emerging evidence, however, suggests that the virus also has the potential to cause infections in Europe, where autochtonous transmission of the virus has been identified. This review focuses on evolving ZIKV epidemiology, modes of transmission and host-virus interactions. The clinical manifestations, diagnostic issues relating to cross-reactivity to the dengue flavivirus and concerns surrounding ZIKV infection in pregnancy are discussed. In the last section, current challenges in treatment and prevention are outlined.

12 January 2017 in Ultrasound in Obstetrics & Gynecology
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LPLéo Pomar
Léo Pomar
GMG. Malinger
G. Malinger
GBGuillaume Benoist
Guillaume Benoist
GCG. Carles
G. Carles
YVY. Ville
Y. Ville
VLV. Lambert
V. Lambert
Objective: To establish the incidence of fetal central nervous system (CNS) anomalies (including microcephaly), signs of congenital infection and fetal loss in pregnant women infected with Zika virus (ZIKV) and non‐infected pregnant women in western French Guiana.Methods: This prospective cohort study was conducted between 1 January and 15 July 2016. We evaluated and compared clinical and fetal ultrasound examinations of 301 pregnant women with biological confirmation of ZIKV infection and 399 pregnant women who were negative for ZIKV infection.Results: Overall, the total number of fetuses with CNS involvement was higher in the infected than in the control group (9.0% vs 4.3%; relative risk, 2.11 (95% CI, 1.18–4.13)). Anomalies of the corpus callosum and presence of cerebral hyperechogenicities were significantly more common in the infected group. There was an increased risk of microcephaly in the infected compared with the control group (1.7% vs 0.3%; relative risk, 6.63 (95% CI, 0.78–57.83)), although this was not statistically significant. When the mother was infected during the first or second trimester, there was a greater risk of severe CNS involvement, more signs of infection and intrauterine fetal death than with infection in the third trimester. The rate of vertical transmission in the exposed group was 10.9%.Conclusion: ZIKV infection during pregnancy is associated with a significant risk of fetal CNS involvement and intrauterine fetal death, particularly when infection occurs during the first or second trimesters. Microcephaly was not present in every case of congenital ZIKV syndrome that we observed. Until more is known about this disease, it is paramount to evaluate suspected cases by detailed neurosonography on a monthly basis, paying particular attention to the corpus callosum and the presence of hyperechogenic foci. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

22 June 2021 in Viruses
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SSSarah Stuckelberger
Sarah Stuckelberger
GFGuillaume FAVRE
Guillaume FAVRE
Michael CeulemansMichael Ceulemans
Michael Ceulemans
HNHedvig Nordeng
Hedvig Nordeng
EGeva victoria gerbier
eva victoria gerbier
LPLéo Pomar
Léo Pomar
As pregnant women are at high risk of severe SARS-CoV-2 infection and COVID-19 vaccines are available in Switzerland, this study aimed to assess the willingness of Swiss pregnant and breastfeeding women to become vaccinated. Through a cross-sectional online study conducted after the first pandemic wave, vaccination practices and willingness to become vaccinated against SARS-CoV-2 if a vaccine was available were evaluated through binary, multi-choice, and open-ended questions. Factors associated with vaccine willingness were evaluated through univariable and multivariable analysis. A total of 1551 women responded to questions related to the primary outcome. Only 29.7% (153/515) of pregnant and 38.6% (400/1036) of breastfeeding women were willing to get vaccinated against SARS-CoV-2 if a vaccine had been available during the first wave. Positive predictors associated with SARS-CoV-2 vaccine acceptance were an age older than 40 years, a higher educational level, history of influenza vaccination within the previous year, having an obstetrician as the primary healthcare practitioner, and being in their third trimester of pregnancy. After the first pandemic wave, Switzerland had a low SARS-CoV-2 vaccination acceptance rate, emphasizing the need to identify and reduce barriers for immunization in pregnant and breastfeeding women, particularly among the youngest and those with a lower educational level.

13 October 2022 in Human Reproduction
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LPLéo Pomar
Léo Pomar
GFGuillaume Favre
Guillaume Favre
CLClaire de Labrusse
Claire de Labrusse
ACAgathe Contier
Agathe Contier
MBMichel Boulvain
Michel Boulvain
DBDavid Baud
David Baud
Did the first wave of the COVID-19 pandemic have an impact on monthly birth rates in Europe? Using datasets on live births per month in Europe, collected from the Human Fertility Database, we found a −14.1% decline in live births in January 2021 (i.e. 9–10 months after the epidemic peaks and first lockdowns), compared to the average number of live births in January 2018 and 2019. Previous pandemics in the 20th and 21st centuries have been associated with a decline in birth rates 9 months after their peak, and a rebound in births over time. Lockdowns were necessary to control the first wave of the COVID-19 pandemic and may have had an impact on subsequent birth rates. Monthly time series data on live births from January 2018 to March 2021 were extracted to provide a time-series analysis of birthrates during and after the first wave of the COVID-19 pandemic in 24 European countries. We conducted a random-effect generalized least squares regression to assess the seasonality of births from January 2018 to March 2021, and to identify potential differences in monthly live births after the first wave of the COVID-19 pandemic, considering the seasonality of births. To quantify these potential differences, we estimated the variation rate between the monthly live births observed during 2020 and 2021 and the mean of the 2018–2019 monthly live births in Europe. Factors potentially associated with a variation in monthly birth rates were assessed using univariable and multivariable generalized linear regressions. When considering the seasonality of births, January 2021 was the only month with a significant difference in live births. A drop of −14.1% was observed compared to the average number of live births in January 2018 and 2019. At the national level, this drop was observed 9–10 months after the epidemic peaks in 13 countries. The duration of lockdowns was the variable that had the stronger association with this decrease, whereas higher incomes per capita could be a factor limiting this decline. A rebound in births compared to the previous years occurred in March 2021 in 13 countries. Our data are based on national data, limiting the power in the multivariable models used and the identification of other potential factors contributing to a decrease or an increase in birth rates. In addition, we collected only live births up to April 2021, which precludes the identification of a difference in births seasonality in 2021. As with previous pandemics, the COVID-19 outbreak was associated with a decline in births 9 months after its first wave. This trend may be associated with the duration of the lockdowns. Although there was a rebound in births in the following months, it does not seem to compensate for this decline. The authors receive no external funding and have no conflict of interest to declare. N/A.

1 June 2021 in Nature Communications
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NHNajeh Hcini
Najeh Hcini
YKYaovi Kugbe
Yaovi Kugbe
ZRZo Hasina Linah Rafalimanana
Zo Hasina Linah Rafalimanana
VLVéronique Lambert
Véronique Lambert
MMMeredith Mathieu
Meredith Mathieu
LPLéo Pomar
Léo Pomar
Little is known about the long-term neurological development of children diagnosed with congenital Zika infection at birth. Here, we report the imaging and clinical outcomes up to three years of life of a cohort of 129 children exposed to Zika virus in utero. Eighteen of them (14%) had a laboratory confirmed congenital Zika infection at birth. Infected neonates have a higher risk of adverse neonatal and early infantile outcomes (death, structural brain anomalies or neurologic symptoms) than those who tested negative: 8/18 (44%) vs 4/111 (4%), aRR 10.1 [3.5–29.0]. Neurological impairment, neurosensory alterations or delays in motor acquisition are more common in infants with a congenital Zika infection at birth: 6/15 (40%) vs 5/96 (5%), aRR 6.7 [2.2–20.0]. Finally, infected children also have an increased risk of subspecialty referral for suspected neurodevelopmental delay by three years of life: 7/11 (64%) vs 7/51 (14%), aRR 4.4 [1.9–10.1]. Infected infants without structural brain anomalies also appear to have an increased risk, although to a lesser extent, of neurological abnormalities. It seems paramount to offer systematic testing for congenital ZIKV infection in cases of in utero exposure and adapt counseling based on these results.