One and a half years into the COVID-19 pandemic - exit strategies and efficacy of SARS-CoV-2 vaccines for holistic management and achieving global control

One and a half years into the pandemic, SARS-CoV-2 is still here to stay. Whilst rapid several effective COVID-19 vaccines have been developed and are being rolled out, the critical questions remain whether vaccines provide widespread protection against infection and reinfection, and what the duration of protection is. Community wide control cannot be obtained until almost everyone is immune. Vaccine production must be ramped up to cover the world population. The price of herd immunity through natural infection is high mortality in the elderly and morbidity in other age groups including children and Long-COVID. We must expect a new wave in the coming winter. The severity will depend on the proportion of the population with immunity from natural infections or immunisation. Therefore, control rests on a population wide immunisation including children, which may or may not need to be repeated if new SARS-CoV-2 variants evolve that can escape immunity from either previous infections or immunisations. Preventing long term sequelae of COVID-19 also remains a priority.

Immunological predictors of disease severity in patients with COVID-19.

BACKGROUND: Identifying the immune cells involved in coronavirus disease 2019 (COVID-19) disease progression and the predictors of poor outcomes is important to manage patients adequately. METHODS: This prospective observational cohort study enrolled 48 patients with COVID-19 hospitalized in a tertiary hospital in Oman and 53 non-hospitalized patients with confirmed mild COVID-19. RESULTS: Hospitalized patients were older (58 years vs 36 years, P < 0.001) and had more comorbid conditions such as diabetes (65% vs 21% P < 0.001). Hospitalized patients had significantly higher inflammatory markers (P < 0.001): C-reactive protein (114 vs 4 mg/l), interleukin 6 (IL-6) (33 vs 3.71 pg/ml), lactate dehydrogenase (417 vs 214 U/l), ferritin (760 vs 196 ng/ml), fibrinogen (6 vs 3 g/l), D-dimer (1.0 vs 0.3 µg/ml), disseminated intravascular coagulopathy score (2 vs 0), and neutrophil/lymphocyte ratio (4 vs 1.1) (P < 0.001). On multivariate regression analysis, statistically significant independent early predictors of intensive care unit admission or death were higher levels of IL-6 (odds ratio 1.03, P = 0.03), frequency of large inflammatory monocytes (CD14+CD16+) (odds ratio 1.117, P = 0.010), and frequency of circulating naïve CD4+ T cells (CD27+CD28+CD45RA+CCR7+) (odds ratio 0.476, P = 0.03). CONCLUSION: IL-6, the frequency of large inflammatory monocytes, and the frequency of circulating naïve CD4 T cells can be used as independent immunological predictors of poor outcomes in COVID-19 patients to prioritize critical care and resources.