Outcome of early cardiopulmonary resuscitation in out-of-hospital cardiac arrest managed in Universiti Kebangsaan Malaysia Medical Centre

Out-of-hospital cardiac arrest (OHCA) patients require immediate cardiopulmonary resuscitation (CPR). Early initiation of CPR and defibrillation before arrival at Emergency Department (ED) increases the chance of survival from sudden cardiac arrest. The main objective of this study was to identify the factors that influenced the outcome of early cardiopulmonary resuscitation (CPR) in out-of-hospital cardiac arrest (OHCA) patients managed at the ED of Universiti Kebangsaan Malaysia Medical Centre (UKMMC). The second objective was to determine the incidence of CPR initiated by the public prior to ambulance arrival. The present study was a one-year cross-sectional study. The OHCA patients were identified from the ED resuscitation logbook. Patients’ medical records were used to obtain details of the resuscitation. Factors recorded included: aetiology of arrest, initiation of on-scene CPR, use of automated external defibrillators (AEDs), mode of transportation and the incidence of return of spontaneous circulation (ROSC) in the ED. Categorical data was analysed using chi-square and Fisher exact tests. Nine patients out of 98 had early CPR. Three patients achieved ROSC. Gender was significantly associated with ROSC (p-value=0.015). More patients who received early CPR achieved ROSC compared to those who received late CPR. The provision of early CPR and usage of AEDs by the public is still low. Female gender had a positive influence on ROSC. Efforts are required to increase the awareness and involvement of the public in initiating early CPR prior to the arrival of ambulance service

Decreased memory B cell frequencies in COVID-19 delta variant vaccine breakthrough infection

The SARS‐CoV‐2 Delta (B.1.617.2) variant is capable of infecting vaccinated persons. An open question remains as to whether deficiencies in specific vaccine‐elicited immune responses result in susceptibility to vaccine breakthrough infection. We investigated 55 vaccine breakthrough infection cases (mostly Delta) in Singapore, comparing them against 86 vaccinated close contacts who did not contract infection. Vaccine breakthrough cases showed lower memory B cell frequencies against SARS‐CoV‐2 receptor‐binding domain (RBD). Compared to plasma antibodies, antibodies secreted by memory B cells retained a higher fraction of neutralizing properties against the Delta variant. Inflammatory cytokines including IL‐1β and TNF were lower in vaccine breakthrough infections than primary infection of similar disease severity, underscoring the usefulness of vaccination in preventing inflammation. This report highlights the importance of memory B cells against vaccine breakthrough and suggests that lower memory B cell levels may be a correlate of risk for Delta vaccine breakthrough infection

Lower vaccine-acquired immunity in the elderly population following two-dose BNT162b2 vaccination is alleviated by a third vaccine dose

Understanding the impact of age on vaccinations is essential for the design and delivery of vaccines against SARS-CoV-2. Here, we present findings from a comprehensive analysis of multiple compartments of the memory immune response in 312 individuals vaccinated with the BNT162b2 SARS-CoV-2 mRNA vaccine. Two vaccine doses induce high antibody and T cell responses in most individuals. However, antibody recognition of the Spike protein of the Delta and Omicron variants is less efficient than that of the ancestral Wuhan strain. Age-stratified analyses identify a group of low antibody responders where individuals ≥60 years are overrepresented. Waning of the antibody and cellular responses is observed in 30% of the vaccinees after 6 months. However, age does not influence the waning of these responses. Taken together, while individuals ≥60 years old take longer to acquire vaccine-induced immunity, they develop more sustained acquired immunity at 6 months post-vaccination. A third dose strongly boosts the low antibody responses in the older individuals against the ancestral Wuhan strain, Delta and Omicron variants