Myocardial Infarction incidence during national lockdown in two French provinces unevenly affected by COVID-19 outbreak: An observational study

International audienceBackground: A reduction of admission for MI has been reported in most countries affected by COVID-19. No clear explanation has been provided.Methods: To report the incidence of myocardial infarction (MI) admission during COVID-19 pandemic and in particular during national lockdown in two unequally affected French provinces (10-million inhabitants) with a different media strategy, and to describe the magnitude of MI incidence changes relative to the incidence of COVID-19-related deaths. A longitudinal study to collect all MIs from January 1 until May 17, 2020 (study period) and from the identical time period in 2019 (control period) was conducted in all centers with PCI-facilities in northern "Hauts-de-France" province and western "Pays-de-la-Loire" Province. The incidence of COVID-19 fatalities was also collected.Findings: In "Hauts-de-France", during lockdown (March 18-May 10), 1500 COVID-19-related deaths were observed. A 23% decrease in MI-IR (IRR=0.77;95%CI:0.71-0.84, p<0.001) was observed for a loss of 272 MIs (95%CI:-363,-181), representing 18% of COVID-19-related deaths. In "Pays-de-la-Loire", 382 COVID-19-related deaths were observed. A 19% decrease in MI-IR (IRR=0.81; 95%CI=0.73-0.90, p<0.001) was observed for a loss of 138 MIs (95%CI:-210,-66), representing 36% of COVID-19-related deaths. While in "Hauts-de-France" the MI decline started before lockdown and recovered 3 weeks before its end, in "Pays-de-la-Loire", it started after lockdown and recovered only by its end. In-hospital mortality of MI patients was increased during lockdown in both provinces (5.0% vs 3.4%, p=0.02).Interpretation: It highlights one of the potential collateral damages of COVID-19 outbreak on cardiovascular health with a dramatic reduction of MI incidence. It advocates for a careful and weighted communication strategy in pandemic crises.Funding: The study was conducted without external funding

Impact of low-dose electron irradiation on n+p silicon strip sensors

The response of n+p silicon strip sensors to electrons from a 90Sr source was measured using a multi-channel read-out system with 25 ns sampling time. The measurements were performed over a period of several weeks, during which the operating conditions were varied. The sensors were fabricated by Hamamatsu Photonics on 200 μm thick float-zone and magnetic-Czochralski silicon. Their pitch was 80 μm, and both p-stop and p-spray isolation of the n+ strips were studied. The electrons from the 90Sr source were collimated to a spot with a full-width-at-half-maximum of 2 mm at the sensor surface, and the dose rate in the SiO2 at the maximum was about 50 Gy(SiO2)/d. After only a few hours of making measurements, significant changes in charge collection and charge sharing were observed. Annealing studies, with temperatures up to 80 °C and annealing times of 18 h showed that the changes can only be partially annealed. The observations can be qualitatively explained by the increase of the positive oxide-charge density due to the ionization of the SiO2 by the radiation from the β source. TCAD simulations of the electric field in the sensor for different oxide-charge densities and different boundary conditions at the sensor surface support this explanation. The relevance of the measurements for the design of n+p strip sensors is discussed