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.

The increasing threat of antimicrobial resistance (AMR) highlights the urgent need for alternative therapeutic strategies, particularly those targeting microbial virulence factors like biofilm formation. This study aimed to isolate and identify Streptomyces species with potential antibiofilm activity against clinically relevant biofilm‐producing bacterial pathogens. Actinomycetes were isolated from soil samples, cultured on Gause’s synthetic agar (GSA) and identified through 16S rRNA gene sequencing. Clinically isolated pathogenic bacteria, including Proteus mirabilis, Escherichia coli, Klebsiella oxytoca, Acinetobacter baumannii, and Klebsiella pneumoniae , were identified using the VITEK 2 system. The antibiofilm and antibacterial activities of the bioactive compounds extracted from Streptomyces spp. were assessed using the agar plug diffusion method and quantitative biofilm assays with crystal violet staining. Among the isolated Streptomyces strains, Streptomyces albogriseolus was identified as a promising producer of bioactive metabolites. The isolate exhibited 99% similarity to strain NBRC 3709 based on 16S rRNA gene sequencing. The crude extract at a concentration of 20 mg/mL demonstrated significant antibacterial activity, with inhibition zones of 11.9 mm against K. pneumoniae and 15.1 mm against E. coli . Moreover, the extract significantly reduced biofilm formation in A. baumannii and E. coli . A lower antibiofilm effect was also observed against K. pneumoniae, P. mirabilis, and K. oxytoca , with K. oxytoca exhibiting the weakest biofilm inhibition. In conclusion, secondary metabolites from S. albogriseolus display significant antibiofilm activity against drug‐resistant pathogens, with efficacy varying by bacterial species and extract concentration. These findings underscore the potential of Streptomyces ‐derived metabolites as promising candidates for combating biofilm‐associated infections. Further studies are recommended to explore their mechanism of action and optimize their potential therapeutic application.