The old and the new: The EG.5 ('Eris') sub-variant of Coronavirus

SARS-CoV-2 JN.1 variant: a short review

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a single-stranded, positive-sense RNA virus. The SARS-CoV-2 virus is evolving continuously, and many variants have been detected over the last few years. SARS-CoV-2, as an RNA virus, is more prone to mutating. The continuous evolution of the SARS-CoV-2 virus is due to genetic mutation and recombination during the genomic replication process. Recombination is a naturally occurring phenomenon in which two distinct viral lineages simultaneously infect the same cellular entity in an individual. The evolution rate depends on the rate of mutation. The rate of mutation is variable among the RNA viruses, with the SARS-CoV-2 virus exhibiting a lower rate of mutation than other RNA viruses. The novel 3'-to-5' exoribonuclease proofreading machinery is responsible for a lower rate of mutation. Infection due to the SARS-CoV-2, influenza, and respiratory syncytial virus has been reported from around the world during the same period of fall and winter, resulting in a "tripledemic." The JN.1 variant, which evolved from the predecessor, the omicron variant BA.2.86, is currently the most dominant globally. The impact of the JN.1 variant on transmissibility, disease severity, immune evasion, and diagnostic and therapeutic escape will be discussed.

Immunogenicity of Tetravalent Protein Vaccine SCTV01E-2 against SARS-CoV-2 EG.5 Subvaraint: A Phase 2 Trial

The Omicron EG.5 lineage of SARS-CoV-2 is currently on a trajectory to become the dominant strain. This phase 2 study aims to evaluate the immunogenicity of SCTV01E-2, a tetravalent protein vaccine, with a specific emphasis on its immunogenicity against Omicron EG.5, comparing it with its progenitor vaccine, SCTV01E (NCT05933512). As of 12 September 2023, 429 participants aged ≥18 years were randomized into the groups SCTV01E (N = 215) and SCTV01E-2 (N = 214). Both vaccines showed increases in neutralizing antibody (nAb) against Omicron EG.5, with a 5.7-fold increase and a 9.0-fold increase in the SCTV01E and SCTV01E-2 groups 14 days post-vaccination, respectively. The predetermined statistical endpoints were achieved, showing that the geometric mean titer (GMT) of nAb and the seroresponse rate (SRR) against Omicron EG.5 were significantly higher in the SCTV01E-2 group than in the SCTV01E group. Additionally, SCTV01E and SCTV01E-2 induced a 5.5-fold and a 5.9-fold increase in nAb against XBB.1, respectively. Reactogenicity was generally mild and transient. No vaccine-related serious adverse events (SAEs), adverse events of special interest (AESIs), or deaths were reported. In summary, SCTV01E-2 elicited robust neutralizing responses against Omicron EG.5 and XBB.1 without raising safety concerns, highlighting its potential as a versatile COVID-19 vaccine against SARS-CoV-2 variants.

Global burden of new-onset hypertension associated with severe acute respiratory syndrome coronavirus 2 infection

Several reports documented a specific effect of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on blood pressure (BP), during and after the acute phase of infection. Clinical studies demonstrated that coronavirus disease 2019 (COVID-19) is associated with an increased risk of a persistent increase in BP requiring a new or intensified anti-hypertensive treatment during hospitalization. The picture is further complicated by the evidence from large databases showing an increased risk of new-onset hypertension in COVID-19 survivors on the long term. To further elucidate the epidemiological burden of this phenomenon, we performed a pooled analysis of 4 studies reporting crude incidence rates of new-onset hypertension among COVID-19 patients and contemporary controls. Overall, COVID-19 was associated with a 65% increased risk of new-onset hypertension when compared with controls (p<0.0001); furthermore, incidence of new-onset hypertension was 9% and 5% among COVID-19 patients and controls, respectively. In both the acute phase and recovery from infection, the interaction between spike proteins of SARS-CoV-2 and angiotensin converting enzyme 2 (ACE2) receptors remain the most plausible mechanism explaining the raise in BP (ranking new onset hypertension as one of the most prevalent cardiovascular sequelae of COVID-19). In this area of research, it is worth to mention that new variants of SARS-CoV-2 exhibit specific mutations in the spike protein that promotes entry into viral cells via ACE2. Thus, the enhanced spike affinity for ACE2 of new variants has the potential to increase the risk of new-onset hypertension when compared with the original Wuhan strain.