ABSTRACT
BACKGROUND: The pandemic of coronavirus disease 2019 (COVID-19) has a broad spectrum of clinical manifestations. The severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) undergoes continuous evolution, resulting in the emergence of several variants. Each variant has a different severity and mortality rate. MATERIALS AND METHODS: In this study, 1174 COVID-19 patients were studied for mortality and severity over three SARS-CoV-2 predominating variant periods in 2021 and 2022 in Sulaimani Province, Iraq. In each period, a representative, variant virus was subjected to phylogenetic and molecular and clinical analysis. RESULTS: Phylogenetic analysis revealed three SARS-CoV-2 variants, belonging to: Delta B.1.617.2, Omicron BA.1.17.2, and Omicron BA.5.6. The Delta variants showed more severe symptoms and a lower PCR-Ct value than Omicron variants regardless of gender, and only 4.3% of the cases were asymptomatic. The mortality rate was lower with Omicron (.5% for BA.5.2 and 1.3% for BA.1.17.2) compared with Delta variants (2.5%). The higher mortality rate with Delta variants was in males (2.84%), while that with Omicron BA1.17.2 and BA.5.2 was in females, 1.05% and .0%, respectively. Age group (≥70) years had the highest mortality rate; however, it was (.0%) in the age group (30-49) years with Omicron variants, compared with (.96%) in Delta variants. CONCLUSIONS: There has been a surge in COVID-19 infection in the city due to the predominant lineages of SARS-CoV-2, B.1.617, Omicron BA.1.17.2 and Omicron BA.5.6, respectively. A higher PCR-Ct value and severity of the Delta variant over Omicron BA.1.17.2 and/or BA.5.2 variants were significantly correlated with a higher death rate in the same order.
ABSTRACT
From March 2021, various countries including Iraq issued prompted recommendations for increased COVID-19 vaccine protection in individuals especially those at risk of catching the virus (i.e., lifestyle, health sector workers, and chronic diseases). It is critically important to understand the impact of COVID-19 vaccinations with the most commonly used vaccines (Pfizer and AstraZeneca) among populations either on the severity of the disease or the transmissibility of SARS-CoV-2 variants of concern (VOCs) and in sequential waves. This study was conducted to establish the clinical severity of COVID-19 caused by Delta and Omicron SARS-CoV-2 variants among patients who either attended or were admitted to hospitals and to compare the effectiveness of Pfizer and AstraZeneca COVID-19 vaccines (single or double doses) at least to prevent hospitalizations if not eradicating the pandemic. A case-control study was done of 570 hospitalized patients; including 328 COVID-19 confirmed patients (166 males, 160 females) who received homologous vaccinations and 242 unvaccinated patients (128 males, 114 females) during the studied waves. The study showed that unvaccinated COVID-19 patients in both waves had expressed significantly a higher number and longer periods of symptoms than vaccinated ones. Additionally, there was no significant effect of vaccine types, Pfizer and AstraZeneca or vaccine shot numbers on the PCR-Ct in the last (Omicron) wave of the pandemic. However, in the previous (Delta) wave of the pandemic, fully vaccinated (double doses) COVID-19 patients had higher PCR-Ct values. Whether among vaccinated or unvaccinated patients, lower CRP levels recorded during the Omicron wave than that of the Delta wave, and regardless of the vaccine type or shot numbers, there were no significant differences between the two waves. Lower WBCs were observed in patients (vaccinated and unvaccinated) infected with the Delta variant in comparison to those infected with the Omicron variant and without any remarkable effect of the vaccine type or shot numbers. This is the first molecular and investigational study of the Delta variant and circulated Omicron in Iraq, regarding the severity of these two waves of SARS-CoV-2 pandemic and the efficacy of homologous vaccination, indicating the insufficiency of two doses and the demand for booster dose(s) as the most effective way of keeping on the safe-side against SARS-CoV-2.