Fetal and Infancy Exposure to Phenols, Parabens, and Phthalates and Anthropometric Measurements up to 36 Months, in the Longitudinal SEPAGES Cohort.

BACKGROUND: Endocrine-disrupting chemicals may play a role in adiposity development during childhood. Until now literature in this scope suffers from methodologic limitations in exposure assessment using one or few urine samples and missing assessment during the infancy period. OBJECTIVES: We investigated the associations between early-life exposure to quickly metabolized chemicals and post-natal growth, relying on repeated within-subject urine collections over pregnancy and infancy. METHODS: We studied the associations of four phenols, four parabens, seven phthalates, and one nonphthalate plasticizer from weekly pooled urine samples collected from the mother during second and third trimesters (median 18 and 34 gestational weeks, respectively) and infant at 2 and 12 months of age, and child growth until 36 months. We relied on repeated measures of height, weight and head circumference from study visits and the child health booklet to predict growth outcomes at 3 and 36 months using the Jenss-Bayley nonlinear mixed model. We assessed associations with individual chemicals using adjusted linear regression and mixtures of chemicals using a Bayesian kernel machine regression model. RESULTS: The unipollutant analysis revealed few associations. Bisphenol S (BPS) at second trimester was positively associated with all infant growth parameters at 3 and 36 months, with similar patterns between exposure at third trimester and all infant growth parameters at 3 months. Mono-n-butyl phthalate (MnBP) at 12 months was positively associated with body mass index (BMI), weight, and head circumference at 36 months. Mixture analysis revealed positive associations between exposure at 12 months and BMI and weight at 36 months, with MnBP showing the highest effect size within the mixture. CONCLUSIONS: This study suggests that exposure in early infancy may be associated with increased weight and BMI in early childhood, which are risk factors of obesity in later life. Furthermore, this study highlighted the impact of BPS, a compound replacing bisphenol A, which has never been studied in this context. https://doi.org/10.1289/EHP13644.

A multidisciplinary and structured investigation of three suspected clusters of transverse upper limb reduction defects in France.

INTRODUCTION: Between 2019-2021, facing public concern, a scientific expert committee (SEC) reanalysed suspected clusters of transverse upper limb reduction defects (TULRD) in three administrative areas in France, where initial investigations had not identified any risk exposure. We share here the national approach we developed for managing suspicious clusters of the same group of congenital anomalies occurring in several areas. METHODS: The SEC analysed the medical records of TURLD suspected cases and performed spatiotemporal analyses on confirmed cases. If the cluster was statistically significant and included at least three cases, the SEC reviewed exposures obtained from questionnaires, environmental databases, and a survey among farmers living near to cases' homes concerning their plant product use. RESULTS: After case re-ascertainment, no statistically significant cluster was observed in the first administrative areas. In the second area, a cluster of four children born in two nearby towns over two years was confirmed, but as with the initial investigations, no exposure to a known risk factor explaining the number of cases in excess was identified. In the third area, a cluster including just two cases born the same year in the same town was confirmed. DISCUSSION: Our experience highlights that in the event of suspicious clusters occurring in different areas of a country, a coordinated and standardised approach should be preferred.

Use of multiple sclerosis disease-modifying therapies during pregnancy in France: Nationwide study between 2010 and 2021.

BACKGROUND: Multiple sclerosis (MS) frequently affects women of childbearing age and pregnant women. OBJECTIVE: To assess the use of MS disease-modifying therapies (DMTs) during pregnancy in France over the last decade, marked by an increasing DMTs availability. METHODS: All pregnancies ended from April 2010 to December 2021 in women with MS were identified based on the nationwide Mother-Child Register EPI-MERES, built from the French National Health Data System (Système National des Données de Santé (SNDS)). RESULTS: Of a total of 20,567 pregnancies in women with MS, 7587 were exposed to DMT. The number of DMT-exposed pregnancies markedly increased from 1079 in 2010-2012 to 2413 in 2019-2021 (+124%), especially those exposed to glatiramer acetate, natalizumab, dimethyl fumarate, and anti-CD20. Among pregnancies of women on DMT 6 months before pregnancy, 78.0% underwent DMT discontinuation and 7.6% switched DMT, generally before (33.0% and 77.0%, respectively) or during the first trimester of pregnancy (58.3% and 17.8%, respectively). DMT discontinuation decreased from 84.0% in 2010-2012 to 72.4% in 2019-2021 and was less frequent among women aged ⩾35 years and those socioeconomically disadvantaged. CONCLUSION: Despite MS therapeutic management adaptations to pregnancy, exposure during pregnancy to treatments whose safety profile has not yet been clearly established has increased sharply over the last decade.

Risk of Guillain-Barré Syndrome Following COVID-19 Vaccines: A Nationwide Self-Controlled Case Series Study.

BACKGROUND AND OBJECTIVES: Guillain-Barré syndrome (GBS) has been inconsistently associated with some coronavirus disease 2019 (COVID-19) vaccines. We aimed to quantify the risk of GBS according to the type of COVID-19 vaccine in a large population. METHODS: Using the French National Health Data System linked to the COVID-19 vaccine database, we analyzed all individuals aged 12 years or older admitted for GBS from December 27, 2020, to May 20, 2022. We estimated the relative incidence (RI) of GBS within 1-42 days after vaccination up to the first booster dose compared with baseline periods using a self-controlled case series design. We then derived the number of cases attributable to the vaccination. Analyses were adjusted for the period and stratified by age group, sex, and for the presence of severe acute respiratory syndrome coronavirus 2 or common acute infections. RESULTS: Of 58,530,770 people aged 12 years or older, 88.8% received at least 1 COVID-19 vaccine dose and 2,229 were hospitalized for GBS during the study period. Patients had a median age of 57 years, and 60% were male patients. The RI of GBS between 1-42 days was 2.5 (95% CI 1.8-3.6) for the first dose of ChAdOx1-S and 2.4 (95% CI 1.2-5.0) for the unique dose of Ad26.COV2.S vaccine. We estimated 6.5 attributable GBS cases per million persons having received a first dose of ChAdOx1-S and 5.7 cases per million for the Ad26.COV2.S vaccine. Except for the age group of 12-49 years after the second dose of the messenger RNA (mRNA)-1273 vaccine (RI 2.6, 95% CI 1.2-5.5), none of the RI estimates were found significantly increased for the mRNA vaccines. DISCUSSION: In summary, we found increased risks of GBS after the first administration of ChAdOx1-S and Ad26.COV2.S vaccines. In this comprehensive assessment at the French population level, there was no statistically significant increase in the risk of GBS after the administration of mRNA vaccines. This is reassuring in the context of the ongoing and future use of mRNA-based booster vaccination.

Protection of COVID-19 Vaccination Against Hospitalization During the Era of Omicron BA.4 and BA.5 Predominance: A Nationwide Case-Control Study Based on the French National Health Data System.

Background: Knowing the duration of effectiveness of coronavirus disease 2019 (COVID-19) booster doses is essential to providing decision-makers with scientific arguments about the frequency of subsequent injections. We estimated the level of protection against COVID-19-related hospitalizations (Omicron BA.4-BA.5) over time after vaccination, accounting for breakthrough infections. Methods: In this nationwide case-control study, all cases of hospitalizations for COVID-19 identified in the comprehensive French National Health Data System between June 1, 2022, and October 15, 2022, were matched with up to 10 controls by year of birth, sex, department, and an individual COVID-19 hospitalization risk score. Conditional logistic regressions were used to estimate the level of protection against COVID-19-related hospitalizations conferred by primary and booster vaccination, accounting for history of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Results: A total of 38 839 cases were matched to 377 653 controls; 19.2% and 9.9% were unvaccinated, respectively, while 68.2% and 77.7% had received ≥1 booster dose. Protection provided by primary vaccination reached 45% (95% CI, 42%-47%). The incremental effectiveness of booster doses ranged from 69% (95% CI, 67%-71%; ≤2 months) to 22% (95% CI, 19%-25%; ≥6 months). Specifically, the second booster provided an additional protection compared with the first ranging from 61% (95% CI, 59%-64%; ≤2 months) to 7% (95% CI, 2%-13%; ≥4 months). Previous SARS-CoV-2 infection conferred a strong, long-lasting protection (51% ≥20 months). There was no incremental effectiveness of a second booster among individuals infected since the first booster. Conclusions: In the era of Omicron BA.4 and BA.5 predominance, primary vaccination still conferred protection against COVID-19 hospitalization, while booster doses provided an additional time-limited protection. The second booster had no additional protection in case of infection since the first booster.

Body composition and anthropometric indicators as predictors of blood pressure: a cross-sectional study conducted in young Algerian adults.

Various body indicators are used to predict health risks. However, controversies still exist regarding the best indicators to predict CVD. Using a large number of measurements, our aim was to assess their associations with blood pressure (BP) and to identify the most relevant parameters to be used in health surveillance studies. The population included 589 students (67·2 % women) aged 20-25 years from Constantine (Algeria). Sixteen parameters were considered, including crude body measurements, ratios and body fat indicators based on bioelectrical impedance analysis (BIA). We used multi-adjusted linear regression models to assess the associations between body measurements and BP. According to WHO definitions, underweight, overweight-without obesity, obesity and hypertension (HT) were identified in 6·1, 18·0, 2·4 and 5·1 % of the subjects, respectively. Prevalence of HT was higher in men than in women (11·9 % v. 1·8 %; P < 0·001). In the whole sample, almost all indicators were positively associated with systolic and diastolic BP. The suprailiac skinfold had the strongest associations with systolic (ß = 3·498; P < 0·001) and diastolic (ß = 2·436; P < 0·001) BP, and as a whole, arm circumferences and weight were also good candidates. The currently used BMI, waist-to-hip, waist-to-height ratio and BIA indictors also predicted BP, but they did not seem to be better determinants of BP than crude anthropometric measurements. This study showed that overweight and HT were already found in the present population of young Algerian adults. Most body indicators were highly associated with BP, but simple anthropometric measurements appeared to be particularly useful to predict BP.

N-nitrosodimethylamine-Contaminated Valsartan and Risk of Cancer: A Nationwide Study of 1.4 Million Valsartan Users.

Background Since July 2018, numerous lots of valsartan have been found to be contaminated with N-nitrosodimethylamine (NDMA). We aimed to assess the association between exposure to valsartan products contaminated with NDMA and the risk of cancer. Methods and Results This study was based on data from the Système National des Données de Santé, which is a national database that includes all French residents' health-related expenses. The target population was consumers of valsartan between January 1, 2013 and December 31, 2017, aged between 40 and 80 years old. The association of exposure to contaminated valsartan with the occurrence of any malignancy and cancer by location was evaluated by fitting Cox proportional hazards models weighted by the inverse probability of treatment. A total of 1.4 million subjects without any history of cancer were included. A total of 986 126 and 670 388 patients were exposed to NDMA-contaminated and uncontaminated valsartan, respectively. The use of the NDMA-contaminated valsartan did not increase the overall risk of cancer (adjusted hazard ratio [aHR], 0.99 [95% CI, 0.98-1.0]). However, exposed patients had a higher risk of liver cancer (aHR, 1.12 [95% CI, 1.04-1.22]) and melanoma (aHR, 1.10 [95% CI, 1.03-1.18]). We estimated a mean of 3.7 and 5.8 extra cases per year per 100 000 person-years of liver cancer and melanoma, respectively. Conclusions Our study was the largest to date to examine cancer risks associated with exposure to NDMA-contaminated valsartan. Our findings suggest a slight increased risk of liver cancer and melanoma in patients exposed to NDMA in regularly taken medications.

Lead Exposure in Infancy and Subsequent Growth in Beninese Children.

Studies suggest that elevated postnatal blood lead levels (BLLs) are negatively associated with child growth. This study aimed to investigate the associations of childhood BLLs at age one year and growth outcomes at age six years (n = 661) in a cohort of children in Allada, Benin. The growth outcomes studied are weight-for-age Z-score (WAZ), height-for-age Z-score (HAZ), BMI-for-age Z-score (BMIZ), weight-for-height Z-score (WHZ), head circumference (HC), growth velocities, underweight, stunting, and wasting. Multivariable regression models examined the associations between BLLs and growth outcomes, with adjustment for potential confounders. The geometric mean BLLs was 59.3 µg/L and 82% of children had BLLs >35 µg/L at the age of 12.8 months. After adjusting for confounding factors, no overall association was found between BLL quartiles and HAZ, WAZ, BMIZ, WHZ, growth velocities, wasting, and underweight. However, boys in the highest quartile had a 1.02 cm lower HC (95% CI: [−1.81, −0.24]) as compared to the lowest quartile. Furthermore, an increased odds of being stunted was observed in children in the highest quartile of exposure compared to the first (OR: 2.43; 95% CI: [1.11−5.33]) which remained statistically significant only among girls in sex-specific strata. Blood lead was found to be associated with an increased risk of childhood stunting and a lower head circumference in a resource-limited setting.

Vaccine effectiveness against severe COVID-19 outcomes within the French overseas territories: A cohort study of 2-doses vaccinated individuals matched to unvaccinated ones followed up until September 2021 and based on the National Health Data System.

IMPORTANCE: Although several observational studies on the effectiveness of SARS-CoV-2 vaccination have been published, vaccination coverage by August, 3 2021, remained low in the French overseas territories, despite Martinique and Guadeloupe experiencing an unprecedented number of COVID-19-related hospitalizations. We aimed to determine the association between COVID-19 vaccination and severe COVID-19 in the French overseas territories. METHODS: The French National Health Data System was used to conduct a 1:1 matched-cohort study. For each individual receiving a first dose of BNT162b2, mRNA-1273, ChAdOx1 nCoV-19, or Ad26.COV2-S vaccine between December 27, 2020, and July 31, 2021, one unvaccinated individual was randomly selected and matched for year of birth, sex, and overseas territories on the date of vaccination. We estimated vaccine effectiveness against COVID-19-related hospitalization and in-hospital death after a full vaccination schedule, defined as ≥14 days after the second dose. Analyses were stratified according to the number of comorbidities. RESULTS: 276,778 vaccinated individuals had a double-dose vaccination during the follow-up period and were followed with their paired unvaccinated control. The average age was 50 years and 53% were women. During a median 77 days of follow-up from day 14 after the second injection, 96 COVID-19-related hospitalizations occurred among vaccinated individuals and 1,465 among their unvaccinated counterparts. Overall, vaccine effectiveness against hospitalization was 94% (95%CI [93-95]) and exceeded 90% in each overseas territory, except Mayotte. The results were similar looking specifically at hospitalizations between July 15 and September 30, 2021. Vaccine effectiveness against in-hospital death was similar (94% [95%CI 91-96]). The risk of COVID-19-related hospitalization increased with the number of comorbidities, especially among vaccinated individuals. CONCLUSIONS AND RELEVANCE: In conclusion, vaccination has a major effect in reducing the risk of severe Covid-19 in the French overseas territories. The risk of COVID-19-hospitalization was very low among vaccinated individuals, especially in the absence of comorbidities. These results aim to increase confidence in vaccine effectiveness in overseas territories in hope of achieving better vaccination coverage.

Risk for Myocardial Infarction, Stroke, and Pulmonary Embolism Following COVID-19 Vaccines in Adults Younger Than 75 Years in France.

BACKGROUND: The BNT162b2 (Pfizer-BioNTech) vaccine has been shown to be safe with regard to risk for severe cardiovascular events (such as myocardial infarction [MI], pulmonary embolism [PE], and stroke) in persons aged 75 years or older. Less is known about the safety of other COVID-19 vaccines or outcomes in younger populations. OBJECTIVE: To assess short-term risk for severe cardiovascular events (excluding myocarditis and pericarditis) after COVID-19 vaccination in France's 46.5 million adults younger than 75 years. DESIGN: Self-controlled case series method adapted to event-dependent exposure and high event-related mortality. SETTING: France, 27 December 2020 to 20 July 2021. PATIENTS: All adults younger than 75 years hospitalized for PE, acute MI, hemorrhagic stroke, or ischemic stroke (n = 73 325 total events). MEASUREMENTS: Linkage between the French National Health Data System and COVID-19 vaccine databases enabled identification of hospitalizations for cardiovascular events (MI, PE, or stroke) and receipt of a first or second dose of the Pfizer-BioNTech, mRNA-1273 (Moderna), Ad26.COV2.S (Janssen), or ChAdOx1 nCoV-19 (Oxford-AstraZeneca) vaccine. The relative incidence (RI) of each cardiovascular event was estimated in the 3 weeks after vaccination compared with other periods, with adjustment for temporality (7-day periods). RESULTS: No association was found between the Pfizer-BioNTech or Moderna vaccine and severe cardiovascular events. The first dose of the Oxford-AstraZeneca vaccine was associated with acute MI and PE in the second week after vaccination (RI, 1.29 [95% CI, 1.11 to 1.51] and 1.41 [CI, 1.13 to 1.75], respectively). An association with MI in the second week after a single dose of the Janssen vaccine could not be ruled out (RI, 1.75 [CI, 1.16 to 2.62]). LIMITATIONS: It was not possible to ascertain the relative timing of injection and cardiovascular events on the day of vaccination. Outpatient deaths related to cardiovascular events were not included. CONCLUSION: In persons aged 18 to 74 years, adenoviral-based vaccines may be associated with increased incidence of MI and PE. No association between mRNA-based vaccines and the cardiovascular events studied was observed. PRIMARY FUNDING SOURCE: None.

Characteristics associated with the residual risk of severe COVID-19 after a complete vaccination schedule: A cohort study of 28 million people in France.

Background: Prior to the availability of vaccines, the risk factors for developing severe forms of COVID-19 were mostly older age and various comorbidities such as diabetes, cardiovascular diseases, mental disorders, transplantations, and kidney disease. Although vaccines have been shown to be highly effective in preventing severe forms of COVID-19, a residual risk may persist, despite vaccination, for certain population groups. Methods: The study was based on data from the national COVID-19 vaccination database (VAC-SI) coupled with the National Health Data System (SNDS), which contains comprehensive reimbursement and hospitalisation data for all of France. All people fully vaccinated by July 31, 2021, with a double-injection vaccine, i.e., the mRNA BNT162b2, mRNA-1273, or ChAdOx1 nCoV-19 vaccines, or a single dose for people with a previous confirmed SARS-CoV-2 infection were included and followed until August 31, 2021. Cox proportional hazard models were performed to estimate adjusted hazard ratios (aHR) for COVID-19-related hospitalisation or in-hospital death associated with age, gender, deprivation index, comorbidities, and immunosuppressive or oral corticosteroid therapy from day 14 after full-vaccination. Findings: In a population of 28,031,641 fully vaccinated individuals with an average follow-up of 80 days, 5,345 (87 hospitalisations per 100,000 person-years) were hospitalised for COVID-19 and 996 (16 in-hospital death per 100,000 person-years) died in hospital. In multivariable analysis, a higher risk was observed with increasing age, male gender, and social deprivation. Most of the 47 chronic conditions considered were positively associated with an increased risk of COVID-19-related hospitalisation and a slight excess risk of death. The risk of hospitalisation and in-hospital death for COVID-19 also increased with the use of immunosuppressants (aHR 3.3 [2.8-3.8] and 2.4 [1.7-3.5], respectively) and oral corticosteroids (aHR 2.8 [2.5-3.1] and 4.1 [3.3-5.1]).Less than 10% (519/5,345) of hospitalised cases and 2% (24/996) of those who died in hospital had no identified comorbidities. There was a strong association between an increasing number of comorbidities and the risk of hospitalisation and in-hospital death (e.g., 5+ versus none, aHR 10.1 95%CI 9.0-11.5 and 17.8 95%CI 11.5-27.4, respectively). Interpretation: Although vaccination has dramatically reduced the occurrence of severe forms of COVID-19, a residual risk remains for the elderly, immunocompromised, and polypathological populations and warrants complementary preventive measures. Funding: None.

Burden and risk factors for relapse following successful treatment of uncomplicated severe acute malnutrition in young children: Secondary analysis from a randomised trial in Niger.

This study aimed to quantify the burden of relapse following successful treatment for uncomplicated severe acute malnutrition (SAM) and to identify associated risk factors in rural Niger. We used data from 1490 children aged 6-59 months discharged as recovered from an outpatient nutritional programme for SAM and followed for up to 12 weeks after admission. Postdischarge SAM relapse was defined as weight-for-height Z-score <-3, mid-upper arm circumference (MUAC) <115 mm or bipedal oedema after having been discharged as recovered. Postdischarge hospitalisation was defined as admission to inpatient SAM treatment or hospitalisation for any cause after having been discharged as recovered. We used multivariate log-binomial models to identify independent risk factors. After programmatic discharge, 114 (8%) children relapsed to SAM and 89 (6%) were hospitalised. Factors associated with SAM relapse were discharge during the lean season (relative risk [RR] = 1.80 [95% confidence interval [CI] = 1.22-2.67]) and larger household size (RR = 1.56 [95% CI = 1.01-2.41]), whereas older child age (RR = 0.94 [95% CI = 0.88-1.00]), higher child MUAC at discharge (RR = 0.93 [95% CI = 0.87-1.00]) and maternal literacy (RR = 0.54 [95% CI = 0.29-0.98]) were protective factors. Discharge during the lean season (RR = 2.27 [95% CI = 1.46-3.51]) was independently associated with postdischarge hospitalisation. Future nutritional programmes in the context of Niger may consider modification of anthropometric discharge criteria or the provision of additional home support or follow-up during the lean season as potential interventions to prevent relapse. More research including postdischarge follow-up is needed to better understand the sustainability of treatment outcomes after discharge and the type of intervention that may best sustain recovery over time. Clinical Trial Registration: ClinicalTrials.gov number, NCT01613547.

No association of low-dose aspirin with severe COVID-19 in France: A cohort of 31.1 million people without cardiovascular disease.

Background: Aspirin at low doses has been reported to be a potential drug candidate to treat or prevent severe coronavirus disease 2019 (COVID-19). Objectives: We aimed to explore whether low-dose aspirin used for primary cardiovascular prevention was associated with a lower risk of severe COVID-19. Method: A large cohort of patients without known cardiovascular comorbidities was constructed from the entire French population registered in national health care databases. In total, 31.1 million patients aged ≥40 years, including 1.5 million reimbursed for low-dose aspirin at least at three time points during the 6 months before the epidemic, were followed until hospitalization with a COVID-19 diagnosis or intubation/death for hospitalized patients. Results: Cox models adjusted for age and sex showed a positive association between low-dose aspirin and the risk of hospitalization (hazard ratio [HR], 1.33; 95% confidence interval (CI), 1.29-1.37]) or death/intubation (HR, 1.40 [95% CI, 1.33-1.47]). In fully adjusted models, associations were close to null (HR, 1.03 [95% CI, 1.00-1.06] and 1.04 [95% CI, 0.98-1.10], respectively). Conclusion: There was no evidence for an effect of low-dose aspirin for primary cardiovascular prevention in reducing severe COVID-19.

Association of Statins for Primary Prevention of Cardiovascular Diseases With Hospitalization for COVID-19: A Nationwide Matched Population-Based Cohort Study.

Background There is little evidence on the relationship between statin use and the risk of hospitalization attributable to COVID-19. Methods and Results The French National Healthcare Data System database was used to conduct a matched-cohort study. For each adult aged ≥40 years receiving statins for the primary prevention of cardiovascular diseases, one nonuser was randomly selected and matched for year of birth, sex, residence area, and comorbidities. The association between statin use and hospitalization for COVID-19 was examined using conditional Cox proportional hazards models, adjusted for baseline characteristics, comorbidities, and long-term medications. Its association with in-hospital death from COVID-19 was also explored. All participants were followed up from February 15, 2020, to June 15, 2020. The matching procedure generated 2 058 249 adults in the statin group and 2 058 249 in the control group, composed of 46.6% of men with a mean age of 68.7 years. Statin users had a 16% lower risk of hospitalization for COVID-19 than nonusers (adjusted hazard ratio [HR], 0.84; 95% CI, 0.81-0.88). All types of statins were significantly associated with a lower risk of hospitalization, with the adjusted HR ranging from 0.75 for fluvastatin to 0.89 for atorvastatin. Low- and moderate-intensity statins also showed a lower risk compared with nonusers (HR, 0.78 [95% CI, 0.71-0.86] and HR, 0.84 [95% CI, 0.80-0.89], respectively), whereas high-intensity statins did not (HR, 1.01; 95% CI, 0.86-1.18). We found similar results with in-hospital death from COVID-19. Conclusions Our findings support that the use of statins for primary prevention is associated with lower risks of hospitalization for COVID-19 and of in-hospital death from COVID-19.

Age and sex-specific risks of myocarditis and pericarditis following Covid-19 messenger RNA vaccines.

Cases of myocarditis and pericarditis have been reported following the receipt of Covid-19 mRNA vaccines. As vaccination campaigns are still to be extended, we aimed to provide a comprehensive assessment of the association, by vaccine and across sex and age groups. Using nationwide hospital discharge and vaccine data, we analysed all 1612 cases of myocarditis and 1613 cases of pericarditis that occurred in France in the period from May 12, 2021 to October 31, 2021. We perform matched case-control studies and find increased risks of myocarditis and pericarditis during the first week following vaccination, and particularly after the second dose, with adjusted odds ratios of myocarditis of 8.1 (95% confidence interval [CI], 6.7 to 9.9) for the BNT162b2 and 30 (95% CI, 21 to 43) for the mRNA-1273 vaccine. The largest associations are observed for myocarditis following mRNA-1273 vaccination in persons aged 18 to 24 years. Estimates of excess cases attributable to vaccination also reveal a substantial burden of both myocarditis and pericarditis across other age groups and in both males and females.

A modified self-controlled case series method for event-dependent exposures and high event-related mortality, with application to COVID-19 vaccine safety.

We propose a modified self-controlled case series (SCCS) method to handle both event-dependent exposures and high event-related mortality. This development is motivated by an epidemiological study undertaken in France to quantify potential risks of cardiovascular events associated with COVID-19 vaccines. Event-dependence of vaccinations, and high event-related mortality, are likely to arise in other SCCS studies of COVID-19 vaccine safety. Using this case study and simulations to broaden its scope, we explore these features and the biases they may generate, implement the modified SCCS model, illustrate some of the properties of this model, and develop a new test for presence of a dose effect. The model we propose has wider application, notably when the event of interest is death.

Effectiveness of BNT162b2, mRNA-1273, and ChAdOx1-S vaccines against severe covid-19 outcomes in a nationwide mass vaccination setting: cohort study.

Objective: To estimate the effectiveness of the three covid-19 vaccines by Pfizer-BioNTech (BNT162b2), Moderna (mRNA-1273), and Oxford-AstraZeneca (ChAdOx1-S) in people after receiving two doses. Design: Cohort study. Setting: Nationwide, population based data in France, from the French National Health Data System (Système National des Données de Santé), between 27 December 2020 and 30 April 2021. Participants: Adults aged ≥50 years receiving a first dose of BNT162b2, mRNA-1273, or ChAdOx1-S were randomly selected (1:1) and matched on the date of vaccination with one unvaccinated control. Individuals were matched on year of birth, sex, region of residence, and residence in a nursing home (for individuals aged ≥75 years). All individuals were followed up until 20 August 2021. Main outcome measures: Primary outcome measure was vaccine effectiveness estimated at least 14 days after the second dose against covid-19 related hospital admission using Cox proportional hazards models adjusted for baseline characteristics and comorbidities. Vaccine effectiveness against covid-19 related death in hospital was also investigated. Results: 11 256 832 vaccinated individuals were included in the study (63.6% (n=7 161 658) with the BNT162b2 vaccine, 7.6% (n=856 599) with the mRNA-1273 vaccine, and 28.8% (n=3 238 575) with the ChAdOx1-S vaccine), along with 11 256 832 matched unvaccinated controls. During follow-up (up to 20 August 2021), 43 158 covid-19 related hospital admissions and 7957 covid-19 related deaths in hospital were registered. Compared with unvaccinated controls, vaccine effectiveness of two doses against covid-19 related hospital admission was 91% (95% confidence interval 91% to 92%), 95% (93% to 96%), and 91% (89% to 94%) for the BNT162b2, mRNA-1273, and ChAdOx1-S vaccines, respectively. Similar results were observed for vaccine effectiveness of two doses against covid-19 related deaths in hospital (BNT162b2, 91% (90% to 93%); mRNA-1273, 96% (92% to 98%); and ChAdOx1 nCoV-19, 88% (68% to 95%)). At 5-6 months after receiving the second dose of vaccine, effectiveness remained high at 94% (92% to 95%) for the BNT162b2 vaccine and 98% (93% to 100%) for the mRNA-1273 vaccine. Vaccine effectiveness of ChAdOx1-S estimated at 3-4 months was 90% (63% to 97%). All three vaccines remained effective at the time of circulation of the delta variant of SARS-CoV-2 between 1 July and 20 August 2021 (effectiveness between 89% and 95%). Conclusions: These findings provide evidence indicating that two doses of ChAdOx1-S is as effective as two doses of mRNA vaccines in France against the alpha and delta variants of SARS-CoV-2. The effectiveness of ChAdOx1-S should be further examined with a longer follow-up and in the light of the circulation of new SARS-CoV-2 variants of concern.