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Background Large randomized controlled trials (RCT) have shown that COVID-19 vaccines are effective at preventing severe COVID-19. However, the RCT's are not powered to detect rare adverse events. It has been reported that the new mRNA based COVID-19 vaccines may increase the risk of thromboembolic and ischemic events. Likewise, thromboembolic and ischemic events are also known complications to infection with SARS-CoV-19. Currently, less is known about the risk-reward relationship of receiving an mRNA-based COVID-19 vaccine versus contracting COVID-19 infection with respect to thromboembolic and ischemic outcomes. Purpose To compare the risk of thromboembolic and ischemic events following COVID-19 vaccination to the risk following infection with SARS-CoV-19. Methods The study period was from March 2020 to August 2021. All individuals were >18 years old. The population was stratified into two different groups. The vaccinated group consisted of recipients of the first dose of either Moderna (mRNA-1273, n=488,220) or Pfizer-BioNTech (BNT162b2 mRNA, n=3,186,164) vaccines. Individuals who had previously tested positive for SARS-CoV-19 were excluded. The other group consisted of individuals who had tested positive for SARS-CoV-19 in the same period who had not yet received their first vaccination dose (n=233,926). The exposure period for both groups was set to 28 days following vaccination/testing positive for SARS-CoV-19 (Figure 1). Patient level data were obtained on all included individuals using nationwide registries. Primary outcomes were acute myocardial infarction (AMI), ischemic stroke, pulmonary embolism (PE), and deep venous thrombosis (DVT). Odds ratios were obtained from logistic regression models with the vaccinated group acting as reference. Multivariable models were adjusted for demographics and comorbidities. Results In the vaccinated group, mean age was 53±19 years and 50.3% were female. In the group of participants testing positive for SARS-CoV-19, mean age was 42.1±17.4 years and 50.2% were female. In total, 773 suffered a stroke, 472 suffered a PE, 500 suffered an AMI, and 484 suffered a DVT during the 28-day exposure period. We observed an increased absolute risk of all outcomes for participants testing positive for SARS-CoV-19 as compared to participants being vaccinated (stroke: 0.049% vs 0.019%, p Conclusion The risks of thromboembolic and ischemic events were substantially higher after SARS-CoV-19 infection than after vaccination in the Danish population. Funding Acknowledgement Type of funding sources: Public hospital(s). Main funding source(s): Gentofte University Hospital

A successful pregnancy is associated with a strong skewing of the immune system towards a Th2-type immune response. Because such a deviation is also the hallmark of allergic disease, it was investigated whether allergic rhinitis in women was associated with an increased likelihood of becoming pregnant and having a successful outcome of pregnancies.Information on allergic rhinitis and reproductive history was obtained for 31145 pregnant women who participated in a national birth cohort study in Denmark during September 1997 to March 2000, and for whom complete information on siblings and place of residence and birth was available via the Civil Registration System. Data were analysed using logistic regression.Women who had previously been pregnant (OR = 0.91, 95% CI 0.85-0.98) or who had given birth previously (OR = 0.91, 95% CI 0.85-0.98) were less likely to report allergic rhinitis than others. The number of previous spontaneous abortions, gestational week of the first spontaneous abortion and fertility treatment were not associated with allergic rhinitis. Women who had waited less than a year to become pregnant more often had allergic rhinitis (OR = 1.18, 95% CI 1.06-1.32, P = 0.002) than women who had waited for more than a year. Early age at menarche was associated with an increased likelihood of allergic rhinitis (Ptrend = 0.003).Our findings did not support the hypothesis that an atopic genotype overall should be associated with an increased likelihood of successful outcome of pregnancies, but it might be associated with a decreased waiting time to pregnancy.

Asthma has been reported to be rare among Inuits, but so far total and specific IgE levels have never been determined in arctic populations.To determine the prevalence of atopy in children living in an arctic environment, and to examine whether atopy and total IgE levels were associated with parental place of birth, as a measure of ethnicity, and travel history.All schoolchildren in Sisimiut, a community on the West coast of Greenland, were screened for atopy. Blood samples were analysed for total IgE and for specific IgE against inhalant and food allergens. Information on place of birth of children and their parents was obtained from national registries. Information on travel history was obtained from self-administered questionnaires.A total of 1031 schoolchildren aged 5 to 18 years had a blood sample drawn (85% of available children for the study). Of these, 151 (14.6%) children were sensitized to at least one inhalant allergen and 42 (4.1%) to at least one food allergen. Sensitization to grass was most common, whereas sensitization to mugwort, birch, animal-dander and house-dust mite was infrequent. Children whose parents were both born abroad had a higher risk of sensitization to inhalant allergens compared with children born of Greenlandic parents (OR = 8.6, 95% CI 2.8-27.1). Furthermore, children who had been abroad had a higher risk of sensitization towards pollen (OR = 1.6, 95% CI 1.0-2.5) and animal-dander (OR = 2.1, 95% CI 1.0-4.6) after adjustment for confounders. Both atopic and non-atopic children demonstrated high levels of total IgE (medians of 251 and 58 kU/L).Compared with European findings Greenlandic children have high levels of total IgE but a low prevalence of allergic sensitization towards inhalant allergens. This may be due to a low genetic susceptibility to atopy and less allergen exposure, as well as to living conditions in an arctic environment.

To determine the risk of adverse pregnancy outcome by maternal serum alpha-fetoprotein (MSAFP) level.We followed 77,149 pregnant women and their infants from MSAFP screening in the 15th to 20th week of gestation until 1 year after birth. Information on pregnancy outcome was obtained from national registries. The relative risks (RRs) and 95% confidence intervals (CIs) for adverse pregnancy outcome were estimated according to the level of MSAFP, with adjustment for confounders.A total of 638 pregnancies resulted in spontaneous abortion, 289 in stillbirth, and 437 in infant death. Compared with women with MSAFP levels at 0.75-1.24 multiples of the median (MoM), those with MSAFP levels greater than or equal to 2.5 MoM had an increased risk of spontaneous abortion (RR 12.5; 95% CI 9.7, 16.1), preterm birth (RR 4.8; 95% CI 4.1, 5.5), small for gestational age (RR 2.8; 95% CI 2.4, 3.2), low birth weight (RR 5.8; 95% CI 5.0, 6.6), and infant death (RR 1.9; 95% CI 1.2, 2.8). Women with MSAFP levels below 0.25 MoM had an increased risk of spontaneous abortion (RR 15.1; 95% CI 9.3, 24.8), preterm birth (RR 2.2; 95% CI 1.3, 3.8), and stillbirth (RR 4.0; 95% CI 1.0, 16.0); those with levels less than 0.5 MoM had an increased risk of infant death (RR 1.9; 95% CI 1.2, 3.0). The increased risk of infant death remained after the subtraction of recognized conditions associated with extreme MSAFP values.Pregnant women with extreme MSAFP values in the second trimester have an increased risk of fetal and infant deaths. Obstet Gynecol 2001;97:277-82.