Comparison of SARS-Cov-2 omicron variant with the previously identified SARS-Cov-2 variants in Egypt, 2020-2022: insight into SARS-Cov-2 genome evolution and its impact on epidemiology, clinical picture, disease severity, and mortality.

BACKGROUND: The o severe acute respiratory coronavirus 2 (SARS-CoV-2) pandemic has killed millions of people and caused widespread concern around the world. Multiple genetic variants of SARS-CoV-2 have been identified as the pandemic continues. Concerns have been raised about high transmissibility and lower vaccine efficacy against omicron. There is an urgent need to better describe how omicron will impact clinical presentation and vaccine efficacy. This study aims at comparing the epidemiologic, clinical, and genomic characteristics of the omicron variant prevalent during the fifth wave with those of other VOCs between May 2020 and April 2022. METHODS: Epidemiological data were obtained from the National Electronic Diseases Surveillance System. Secondary data analysis was performed on all confirmed COVID-19 patients. Descriptive data analysis was performed for demographics and patient outcome and the incidence of COVID-19 was calculated as the proportion of SARS-CoV-2 confirmed patients out of the total population of Egypt. Incidence and characteristics of the omicron cohort from January- April 2022, were compared to those confirmed from May 2020-December 2021. We performed the whole-genome sequencing of SARS-CoV-2 on 1590 specimens using Illumina sequencing to describe the circulation of the virus lineages in Egypt. RESULTS: A total of 502,629 patients enrolled, including 60,665 (12.1%) reported in the fifth wave. The incidence rate of omicron was significantly lower than the mean of incidences in the previous subperiod (60.1 vs. 86.3/100,000 population, p < 0.001). Symptoms were reported less often in the omicron cohort than in patients with other variants, with omicron having a lower hospitalization rate and overall case fatality rate as well. The omicron cohort tended to stay fewer days at the hospital than did those with other variants. We analyzed sequences of 2433 (1590 in this study and 843 were obtained from GISAID platform) Egyptian SARS-CoV-2 full genomes. The first wave that occurred before the emergence of global variants of concern belonged to the B.1 clade. The second and third waves were associated with C.36. Waves 4 and 5 included B.1.617.2 and BA.1 clades, respectively. CONCLUSIONS: The study indicated that Omicron-infected patients had milder symptoms and were less likely to be hospitalized; however, patients hospitalized with omicron had a more severe course and higher fatality rates than those hospitalized with other variants. Our findings demonstrate the importance of combining epidemiological data and genomic analysis to generate actionable information for public health decision-making.

Clinical features and severe outcome predictors of COVID-19 vaccine breakthrough infection among hospitalized patients: results from Egypt severe acute respiratory infections sentinel surveillance, 2021-2022.

BACKGROUND: COVID-19 vaccines are effective against infections and outcomes; however, breakthrough infections (VBT) are increasingly reported, possibly due to waning of vaccine-induced immunity or emerging variants. Most studies have focused on determining VBT rate based on antibody levels. This study aims at describing clinical features, risks, time trends, and outcomes of COVID-19 VBT among hospitalized patients in Egypt. METHODS: Data of SARS-CoV-2 confirmed patients hospitalized in 16 hospitals was obtained from the severe acute respiratory infections surveillance database, September 2021-April 2022. Data includes patients' demographics, clinical picture, and outcomes. Descriptive analysis was performed and patients with VBT were compared to not fully vaccinated (UPV). Bivariate and multivariate analyses were performed using Epi Info7 with a significance level < 0.05 to identify VBT risk factors. RESULTS: Overall, 1,297 patients enrolled, their mean age 56.7 ± 17.0 years, 41.5% were males, 64.7% received inactivated, 25.% viral vector, and 7.7% mRNA vaccine. VBT was identified in 156(12.0%) patients with an increasing trend over time. VBT significantly was higher in (16-35 years) age, males, in those who received inactivated vaccine compared to corresponding groups of UPV (14.1 vs. 9.0%, p < 0.05 and 57.1 vs. 39.4%, p < 0.001 and 64.7 vs. 45.1, p < 0.01 respectively). Whereas receiving mRNA vaccine was significantly protective against VBT (7.7 vs. 21.6%, p < 001). VBT patients tend to have shorter hospital stays and lower case fatality (mean hospital days = 6.6 ± 5.5 vs. 7.9 ± 5.9, p < 0.01 and CFR = 28.2 vs. 33.1, p < 0.01 respectively). MVA identified younger ages, male gender, and inactivated vaccines as risks for VBT. CONCLUSION: The study indicated that COVID-19 vaccines significantly reduce hospital days and fatality. VBT trend is on the rise and males, young ages, and inactivated vaccine receivers are at higher risk. Caution regarding relaxation of personal preventive measures in areas with higher or increasing incidences of COVID-19, particularly for the at-risk group even if they are vaccinated. The vaccination strategy should be revised to reduce VBT rate and increase vaccine effectiveness.