Impact of social and demographic factors on the spread of the SARS-CoV-2 epidemic in the town of Nice.

INTRODUCTION: Socio-demographic factors are known to influence epidemic dynamics. The town of Nice, France, displays major socio-economic inequalities, according to the National Institute of Statistics and Economic Studies (INSEE), 10% of the population is considered to live below the poverty threshold, i.e. 60% of the median standard of living. OBJECTIVE: To identify socio-economic factors related to the incidence of SARS-CoV-2 in Nice, France. METHODS: The study included residents of Nice with a first positive SARS-CoV-2 test (January 4-February 14, 2021). Laboratory data were provided by the National information system for Coronavirus Disease (COVID-19) screening (SIDEP) and socio-economic data were obtained from INSEE. Each case's address was allocated to a census block to which we assigned a social deprivation index (French Deprivation index, FDep) divided into 5 categories. For each category, we computed the incidence rate per age and per week and its mean weekly variation. A standardized incidence ratio (SIR) was calculated to investigate a potential excess of cases in the most deprived population category (FDep5), compared to the other categories. Pearson's correlation coefficient was computed and a Generalized Linear Model (GLM) applied to analyse the number of cases and socio-economic variables per census blocks. RESULTS: We included 10,078 cases. The highest incidence rate was observed in the most socially deprived category (4001/100,000 inhabitants vs 2782/100,000 inhabitants for the other categories of FDep). The number of observed cases in the most social deprivated category (FDep5: N = 2019) was significantly higher than in the others (N = 1384); SIR = 1.46 [95% CI:1.40-1.52; p < 0.001]. Socio-economic variables related to poor housing, harsh working conditions and low income were correlated with the new cases of SARS-CoV-2. CONCLUSION: Social deprivation was correlated with a higher incidence of SARS-CoV-2 during the 2021 epidemic in Nice. Local surveillance of epidemics provides complementary data to national and regional surveillance. Mapping socio-economic vulnerability indicators at the census block level and correlating these with incidence could prove highly useful to guide political decisions in public health.

Cancer incidence in the vicinity of a waste incineration plant in the Nice area between 2005 and 2014.

INTRODUCTION: Few studies on cancer incidence have been conducted since the adoption of the EU 2000/76/EC waste incineration directive which aimed to limit dioxin emission levels to less than 0.1 ng TEQ/m3 before December 31, 2005. OBJECTIVE: To measure cancer incidence among the population exposed to atmospheric emissions from the waste incineration plant near the town of Nice (South-Eastern France), compared to the unexposed population of the Alpes-Maritimes department (A-M). METHODS: All primary invasive cancers and haematological malignancies diagnosed among AM residents between 2005 and 2014 were recorded. The exposed surface was modeled on an average dioxin deposition model ≥4.25 ng/m2/year. Each case was geolocated and assigned to one of 36 predefined geographic units of exposed area, or one of 462 units in the unexposed area. The adjusted incidence rate, the standardized incidence ratio and the Comparative Morbidity Figure were calculated for two periods: 2005-2009/2010-2014. RESULTS: We recorded 80,865 new cancers in the A-M population. Between 2005 and 2009, we observed a higher incidence among exposed women of acute myeloid leukaemia, myelodysplastic syndromes and myeloma and, among exposed men, of soft tissue sarcomas, myeloma and lung cancer. Between 2010 and 2014, there was no excess incidence among women, while among men incidence of myeloma and lung cancer remained higher. CONCLUSION: Only among men, the incidence of myeloma and lung cancer remained higher in the exposed area during the second period. The EU directive resulting in the limitation of atmospheric emissions from incinerators could explain the decrease in incidence of cancers with protracted latency. Consideration of other risk factors and further data collection will be necessary to validate this hypothesis.