A haemochromatosis-causing HFE mutation is associated with SARS-CoV-2 susceptibility in the Czech population

Iron nutrition and COVID-19 among Nigerian healthcare workers

Background and objectives

The optimal iron hypothesis (OIH) posits that risk for infection is lowest at a mild level of iron deficiency. The extent to which this protection results from arms race dynamics in the evolution of iron acquisition and sequestration mechanisms is unclear. We evaluated the OIH with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), an emerging infectious agent.

Methodology

We tested 304 healthcare workers at baseline for iron deficiency (zinc protoporphyrin:heme), anemia (hemoglobin), and SARS-CoV-2 (salivary PCR), and followed them for ~3 months with biweekly SARS-CoV-2 tests. We fit logistic regression models based on Akaike Information Criterion.

Results

Adequate data were available for 199 participants. Iron replete (OR: 2.87, 95% CI: 0.85, 9.75) and anemia (OR: 2.48; 95% CI: 0.82, 7.85) were associated with higher risk for SARS-CoV-2 infection after control for covariates. Logistic regression and Cox proportional hazards models of the SARS-CoV-2 outcome were similar. Anemia (OR: 1.81; 95% CI: 0.88, 3.71) was associated with respiratory symptoms regardless of SARS-CoV-2 infection.

Conclusions and implications

These findings provide partial support for the OIH: SARS-CoV-2 infection risk was elevated at the high end of the range of iron availability; however, the elevated risk among those with anemia was not, as expected, specific to severe iron deficiency. Narrowly, for COVID-19 epidemiology, these findings accord with evidence that SARS-CoV-2's ability to establish infection is enhanced by access to iron. More broadly, these findings suggest that the OIH does not hinge on a long history of evolutionary arms race dynamics in access to host iron.

Association of iron deficiency anaemia with the hospitalization and mortality rate of patients with COVID‑19

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) illness led to the coronavirus disease 2019 (COVID-19) pandemic, which has caused enormous health and financial losses, as well as challenges to global health. Iron deficiency anaemia (IDA) has been linked to adverse outcomes in patients infected with SARS-COV-2. The present study aimed to assess the association between IDA and the severity of COVID-19 in hospitalized patients. For this purpose, a retrospective data analysis of 100 patients with COVID-19 was conducted. Data of patients hospitalized with SARS-COV-2 infection confirmed by RT-PCR were collected between June, 2021 and March, 2022. The collected data included patient demographics, comorbidities, clinical signs, symptoms and IDA medical laboratory findings, including complete blood count and iron profiles. The results revealed that patients with COVID-19 admitted to the isolation unit represented 61.0% of the study sample, whereas 39.0% were admitted to the intensive care unit (ICU). No patients had stage I IDA, whereas 4 patients (4%) had stage II IDA. Furthermore, 19 patients (19.0%) had stage III IDA. A significantly higher proportion of patients with IDA (69.6%) were admitted to the ICU compared with those without IDA (29.9%, P<0.001). Additionally, patients with IDA had a higher proportion of a history of stroke compared with those without IDA (17.4 vs. 2.6%, respectively, P=0.024). The most common comorbidities identified were hypertension (29%), diabetes (23%) and heart problems (17%). On the whole, the present study demonstrates significant associations between IDA and a longer hospitalization period. A greater incidence of complications was observed in the hospitalized patients who were SARS-COV-2-positive. Although further studies with larger sample sizes are required to confirm these findings, the results presented herein may provide insight for physicians as regards the prevention and treatment of patients with IDA who are infected with coronavirus.

Possible effect of OAS1 and TMPRSS6 but not DPP4 and ZNF335 polymorphisms on COVID-19 severity in the Czech population

OBJECTIVES

The acute respiratory syndrome, known as COVID-19, is characterised by high morbidity and increased mortality. Genetic factors may partially explain the differences in susceptibility to and severity of COVID-19.

METHODS

We have analysed common functional polymorphisms within the OAS1 (rs4767027), TMPRSS6 (rs855791), DPP4 (rs3788979), and ZNF335 (rs3848719) genes in SARS-CoV-2 positive subjects (n = 521, different disease severity) and in population controls (n = 2,559 subjects, COVID-19 status unknown).

RESULTS

Neither DPP4 nor ZNF335 were associated with disease susceptibility or severity in the Czech population in any of the models used for calculation. T allele carriers of the OAS1 polymorphism seem to be protective against symptomatic COVID-19 (p = 0.002 calculated for trend; asymptomatic, symptomatic, hospitalised). Similarly, within the TMPRSS6, minor TT homozygotes associated with lower plasma Fe concentrations were underrepresented in the overall patient group (p = 0.044; OR = 0.77, 95% CI: 0.59-0.99), and the difference was mainly driven by the severe COVID-19 subjects. In general, risky homozygotes of these two polymorphisms were less frequent than expected in the group of hospitalised COVID-19 survivors.

CONCLUSIONS

Common variants within OAS1 (rs4767027) and TMPRSS6 (rs855791) play some role in COVID-19 pathology in the Czech Caucasian population. Whether the depletion of minor allele carriers of these two variants is associated with increased COVID-19 mortality, needs to be analysed in an external confirmatory study.

ABCA3 and LZTFL1 Polymorphisms and Risk of COVID-19 in the Czech Population

SARS-CoV-2 infection, which causes the respiratory disease COVID-19, has spread rapidly from Wuhan, China, since 2019, causing nearly 7 million deaths worldwide in three years. In addition to clinical risk factors such as diabetes, hypertension, and obesity, genetic variability is an important predictor of disease severity and susceptibility. We analyzed common polymorphisms within the LZTFL1 (rs11385942) and ABCA3 (rs13332514) genes in 519 SARS-CoV-2-positive subjects (164 asymptomatic, 246 symptomatic, and 109 hospitalized COVID-19 survivors) and a population-based control group (N?=?2,592; COVID-19 status unknown). Rare ABCA3 AA homozygotes (but not A allele carriers) may be at a significantly increased risk of SARS-CoV-2 infection [P?=?0.003; OR (95 % CI); 3.66 (1.47-9.15)]. We also observed a borderline significant difference in the genotype distribution of the LZTFL1 rs11385942 polymorphism (P?=?0.04) between the population sample and SARS-CoV-2-positive subjects. In agreement with previous studies, a nonsignificantly higher frequency of minor allele carriers was detected among hospitalized COVID-19 subjects. We conclude that a common polymorphism in the ABCA3 gene may be a significant predictor of susceptibility to SARS-CoV-2 infection.

CD14 Polymorphism Is Not Associated with SARS-CoV-2 Infection in Central European Population

A 2021 in silico study highlighted an association between the CD14 polymorphism rs2569190 and increased susceptibility to SARS-CoV-2, which causes coronavirus disease 2019 (COVID-19). The aim of our study was to confirm this finding. We analysed the CD14 polymorphism (C→T; rs2569190) in 516 individuals who tested positive for SARS-CoV-2, with differing disease severity (164 asymptomatic, 245 symptomatic, and 107 hospitalized). We then compared these patients with a sample from the general population consisting of 3,037 individuals using a case-control study design. In comparison with carriers of the C allele, TT homozygotes accounted for 21.7 % of controls and 20.5 % in SARS-CoV-2-positive individuals (P = 0.48; OR; 95 % CI - 0.92; 0.73-1.16). No significant differences in the distribution of genotypes were found when considering co-dominant and recessive genetic models or various between-group comparisons. The CD14 polymorphism is unlikely to be an important predictor of COVID-19 in the Caucasian population in Central Europe.