All currently approved COVID-19 vaccines utilize the spike protein as their immunogen. SARS-CoV-2 variants of concern (VOCs) contain mutations in the spike protein, enabling them to escape infection- and vaccination-induced immune responses to cause reinfection. New vaccines are hence being researched intensively. Studying SARS-CoV-2 epitopes is essential for vaccine design, as identifying targets of broadly neutralizing antibody responses and immunodominant T-cell epitopes reveal candidates for inclusion in next-generation COVID-19 vaccines. We summarize the major studies which have reported on SARS-CoV-2 antibody and T-cell epitopes thus far. These results suggest that a future of pan-coronavirus vaccines, which not only protect against SARS-CoV-2 but numerous other coronaviruses, may be possible. The T-cell epitopes of SARS-CoV-2 have gotten less attention than neutralizing antibody epitopes but may provide new strategies to control SARS-CoV-2 infection. T-cells target many SARS-CoV-2 antigens other than spike, recognizing numerous epitopes within these antigens, thereby limiting the chance of immune escape by VOCs that mainly possess spike protein mutations. Therefore, augmenting vaccination-induced T-cell responses against SARS-CoV-2 may provide adequate protection despite broad antibody escape by VOCs.

Hypertrophic cardiomyopathy (HCM) is a group of heterogeneous disorders that are most commonly passed on in a heritable manner. It is a relatively rare disease around the globe, but due to increased rates of consanguinity within the Kingdom of Saudi Arabia, we speculate a high incidence of undiagnosed cases. The aim of this paper is to elucidate a systematic approach in dealing with HCM patients and since HCM has variable presentation, we have summarized differentials for diagnosis and how different subtypes and genes can have an impact on the clinical picture, management and prognosis. Moreover, we propose a referral multi-disciplinary team HCM-Family Unit in Saudi Arabia and an integrated role in a network between King Faisal Hospital and Inherited and Rare Cardiovascular Disease Unit-Monaldi Hospital, Italy (among the 24 excellence centers of the European Reference Network (ERN) GUARD-Heart).   Graphical Abstract

Age and sex differences in Takotsubo syndrome (TTS) are still a matter of debate. The aim of the present study was to evaluate the difference in cardiovascular (CV) risk factors, CV disease, in-hospital complications, and death within different sex-age groups. Using the National Inpatient Sample database between 2012 and 2016, 32,474 patients older than 18 years of age hospitalized with the primary diagnosis of TTS were identified. A total of 32.474 patients were enrolled, 27,611 (85.04%) were females. Cardiovascular risk factors were higher in females while CV diseases and in-hospital complications were significantly higher in males. The mortality in males was twice as high as that of female patients (9.83% vs 4.58%, p<0.01) and in logistic regression model after adjustment for confounders, odds ratio was 1.79, CI 1.60-2.02, p<0.01. After dividing the group based on age, in-hospital complications were inversely related to age in both sexes, and the length of in-hospital stay was double in the youngest group compared to the oldest one. Mortality increased progressively with age in both groups but was constantly higher in males for each age group. A multiple logistic regression analysis for mortality was performed for the two sexes separately and the 3 age groups considering the youngest one as the reference group. In females, the OR was 1.59 and 2.88 respectively for group 2 and 3, for males OR was 1.92 and 3.15, all of them statistically significant (p<0.01). In-hospital complications were more common in younger patients with TTS and particularly in males. Mortality was positively correlated with age for both sexes, but mortality was higher in males compared to females in all age groups.

Recently, researchers in our laboratory have shown that humans with genetic mutations resulting in high-affinity haemoglobin (HAH) demonstrate better maintained aerobic capacity and peak power output during hypoxic exercise versus normoxic exercise in comparison to humans with normal-affinity haemoglobin.However, the influence of HAH on tissue oxygenation within exercising muscle during normoxia and hypoxia is unknown. Therefore, we examined near-infrared spectroscopy-derived oxygenation profiles of the vastus lateralis during graded cycling exercise in normoxia and hypoxia among humans with HAH (n = 5) and control subjects with normal-affinity haemoglobin (n = 12). The HAH group elicited a blunted increase of deoxygenated haemoglobin + myoglobin during hypoxic exercise compared with the control group (P = 0.03), suggesting reduced fractional oxygen extraction in the HAH group. In addition, the HAH group maintained a higher level of muscle tissue oxygen saturation during normoxic exercise (HAH, 75 ± 4% vs. controls, 65 ± 3%, P = 0.049) and there were no differences between groups in muscle tissue oxygen saturation during hypoxic exercise (HAH, 68 ± 3% vs. controls, 68 ± 2%, P = 0.943).Overall, our results suggest that humans with HAH might demonstrate divergent patterns of fractional oxygen extraction during hypoxic exercise and elevated muscle tissue oxygenation during normoxic exercise compared with control subjects.