Since the first detection of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the virus remains a public health concern. Several public health measures have been implemented in an effort to curb the infections. However, the effectiveness of these strategies was threatened with the emergence of numerous SARS-CoV-2 variants in all parts of the globe, due to the persistent mutations as part of the viral evolution. Mutations that usually occur in its spike glycoprotein, allow SARS-CoV-2 to possess advantageous characteristics for its survivability and persistence. This has led to poor performance of diagnostic kits which have caused non-specific and insensitive detection of these variants, resulting in undetermined infection. The variants also have caused the increased severity of COVID-19, involving hospitalisation rates, ICU admissions, and deaths. Many have reported the vaccine-breakthrough infections and reduced effectiveness of vaccination, which is supposed to provide an effective degree of protection against COVID-19 infections. Due to these issues, this review summarises the impacts related to SARS-CoV-2 variants emergence towards the performance of diagnostic kits, transmissibility of the virus, severity of disease, and effectiveness of COVID-19 vaccines.

A myrid of aptamers were isolated thus far against SARS-CoV-2 by using in silico selection.

Pseudomonas aeruginosa is an opportunistic pathogen which is commonly associated with healthcare associated infection. They possess multiple pathogenic factors which play a role in causing invasive infections such as surgical site infection, pneumonia, and blood stream infection. There were two hospital outbreaks caused by sensitive strains P. aeruginosa between 2016 and 2017 involving 17 patients. The outbreak investigation by Pulsed Field Gel Electrophoresis (PFGE) revealed seven clonally related P. aeruginosa strains (A-G). This study aims to determine the virulence factors acquired by the P. aeruginosa isolates and describe the clinical outcome of the patients. Seventeen P. aeruginosa isolates from the stocked collection were retrieved for six virulence genes, namely ToxA, ExoS, LasI, LasB, OprI, and OprL by PCR. Ten out of 17 of the P. aeruginosa isolates were able to revive. The ExoS, LasI, LasB, OprI, and OprL genes, respectively, were detected in all isolates, while ToxA gene was detected in six isolates which belonged to clone A (one isolate) and clone C (five isolates). The isolate from clone A caused pneumonia and isolates from clone C caused surgical site infections which led to disseminated infections and death. The presence of multiple virulence genes in these P. aeruginosa isolates may have contributed to the invasiveness, and the outcome of the infection. More studies with a larger number of patients will give a better insight regarding the actual role of these genes in different clinical manifestations caused by sensitive strain P. aeruginosa.

The dynamics and protectiveness of the hybrid immune responses, especially in individuals who have experienced severe COVID-19, remain to be fully understood. This study aims to identify the prevalence and persistence of neutralising antibodies throughout time, and to investigate the longitudinal profile of anti-SARS-CoV-2 IgG antibodies targeting the receptor binding domain (RBD) in patients recovering from severe COVID-19. A total of 42 hospitalised COVID-19 survivors were enrolled from three medical centres in Malaysia. Serial blood samples were collected at four time points post-discharge (approximately 90, 180, 270 and 360 days). IgG titres were quantified using ELISA and neutralising antibodies (NAbs). Statistical analyses were performed to explore antibody dynamics and correlations. Among 42 participants, 24 completed all four visits. Mean antibody titre showed an initial decline after the first visit, followed by a gradual increase over time, with the highest being at Visit 4 (360-390 days post-discharge). The highest titre (266.7 ± 30.9 BAU/mL) was observed in a recipient, 10 days after receiving the fourth vaccination. All participants except one demonstrated protective NAbs at the final visit. Higher BMI was significantly associated with disease severity (P = 0.006), while IgG titres were higher in individuals with more severe initial infections (Category 5). This study highlights the persistence of antibody response with hybrid immunity, with the booster vaccinations contributing to increased antibody titres. RBD-specific IgG titres provide useful insights into their trends, while the concurrent NAbs assessment is important for a comprehensive understanding of the protective efficacy following hybrid immunity.

Genomic surveillance activity is a useful tool in epidemiologic investigations and monitoring of virus evolution. This study aimed to describe the COVID-19 outbreaks through SARS-CoV-2 virus genomic surveillance by whole genome sequencing. A cross-sectional study was conducted using archived clinical samples of confirmed laboratory-positive COVID-19 from June 2021 to June 2022 from a tertiary center in Malaysia. The samples were subjected to whole genome sequencing. A phylogenetic tree was constructed using the maximum likelihood method in MEGA 11 software. The clinical data were obtained through paper, electronic, and hospital information systems. A total of 86 clinical samples were successfully sequenced. The phylogenetic tree revealed seven clusters, consisting of 24 cases. Three clusters were associated with health care workers and health care-associated individuals. The SARS-CoV-2 Delta variants were observed in the first three clusters and subsequently replaced with the Omicron variants. Whole genome sequencing is robust and reliable, enhancing epidemiologic investigations, leading to the identification of clusters and preventing the spreading of COVID-19 among health care workers. Monitoring of the SARS-CoV-2 variants is necessary to study the viral dynamics and maintain the effectiveness of public health interventions.