The COVID-19 pandemic proceeds in waves, with variable characteristics of the clinical picture resulting from the evolution of the SARS-CoV-2 virus. This study aimed to compare the epidemiological characteristics, symptomatology, and outcomes of the disease in patients hospitalized for COVID-19 during periods of different variants dominance. Comparing the periods of dominance of variants preceding the Delta variant, the Delta period was characterized by a higher share of hospitalized females, less frequent comorbidities among patients, and a different age distribution. The lowest need for oxygen therapy and mechanical ventilation was observed under Omicron dominance. The triad of classic COVID-19 symptoms, cough, fever, dyspnoea, and fatigue, were most prevalent during the Delta period, and significantly less common under the Omicron dominance. During the Omicron period, nearly twice as many patients as in the previous periods could be discharged from the hospital within 7 days; the overall 28-day mortality was significantly lower compared to that of the Delta period. It also did not differ between periods that were dominated by the BA.1 and BA.2 subvariants. The study indicates that the Omicron SARS-CoV-2 variant that dominated between January and June 2022 caused a disease which resembled the common cold, and was caused by seasonal alpha and beta-coronaviruses with a low pathogenicity for humans. However, one should note that this effect may not only have been related to biological features of the Omicron lineage, but may additionally have been driven by the increased levels of immunization through natural infections and vaccinations, for which we could not account for due to a lack of sufficient data.

This study aimed to compare the clinical picture of COVID-19 in the initial and later period of Omicron dominance and to identify populations still at risk. A retrospective comparison of the clinical data of 965 patients hospitalized during the early period of Omicron’s dominance (EO, January–June 2022) with 897 patients from a later period (LO, July 2022–April 2023) from the SARSTer database was performed. Patients hospitalized during LO, compared to EO, were older, had a better clinical condition on admission, had a lower need for oxygen and mechanical ventilation, had less frequent lung involvement in imaging, and showed much faster clinical improvement. Moreover, the overall mortality during EO was 14%, higher than that in LO—9%. Despite the milder course of the disease, mortality exceeding 15% was similar in both groups among patients with lung involvement. The accumulation of risk factors such as an age of 60+, comorbidities, lung involvement, and oxygen saturation <90% resulted in a constant need for oxygen in 98% of patients, an 8% risk of mechanical ventilation, and a 30% mortality rate in the LO period. Multiple logistic regression revealed lower odds of death during the LO phase. Despite the milder course of infections caused by the currently dominant subvariants, COVID-19 prophylaxis is necessary in people over 60 years of age, especially those with comorbidities, and in the case of pneumonia and respiratory failure.

Difficult-to-treat populations with chronic hepatitis C (CHC), in the era of interferon treatment, included patients with liver cirrhosis, kidney impairment, treatment-experienced individuals, and those coinfected with the human immunodeficiency virus. The current study aimed to determine whether, in the era of direct-acting antivirals (DAA), there are still patients that are difficult-to-treat. The study included all consecutive patients chronically infected with hepatitis C virus (HCV) who started interferon-free therapy between July 2015 and December 2020 in the Department of Infectious Diseases in Kielce. The analyzed real-world population consisted of 963 patients, and most of them were infected with genotype 1 (87.6%) with the predominance of subtype 1b and were treatment-naïve (78.8%). Liver cirrhosis was determined in 207 individuals (21.5%), of whom 82.6% were compensated. The overall sustained virologic response, after exclusion of non-virologic failures, was achieved in 98.4%. The univariable analysis demonstrated the significantly lower response rates in males, patients with liver cirrhosis, decompensation of hepatic function at baseline, documented esophageal varices, concomitant diabetes, body mass index ≥25, and previous ineffective antiviral treatment. Despite an overall very high effectiveness, some unfavorable factors, including male gender, genotype 3 infection, liver cirrhosis, and treatment experience, significantly reduce the chances for a virologic response were identified.

The hepatitis B virus (HBV) continues to cause substantial health and economic burdens, and its target of elimination may not be reached in 2030 without further efforts in diagnostics, non-pharmaceutical prevention measures, vaccination, and treatment. Current therapeutic options in chronic HBV, based on interferons and/or nucleos(t)ide analogs, suppress the virus replication but do not eliminate the pathogen and suffer from several constraints. This paper reviews the progress on biotechnological approaches in functional and definitive HBV treatments, including gene-editing tools, i.e., zinc-finger proteins, transcription activator-like effector nucleases, and CRISPR/Cas9, as well as therapeutics based on RNA interference. The advantages and challenges of these approaches are also discussed. Although the safety and efficacy of gene-editing tools in HBV therapies are yet to be demonstrated, they show promise for the revitalization of a much-needed advance in the field and offer viral eradication. Particular hopes are related to CRISPR/Cas9; however, therapeutics employing this system are yet to enter the clinical testing phases. In contrast, a number of candidates based on RNA interference, intending to confer a functional cure, have already been introduced to human studies. However, larger and longer trials are required to assess their efficacy and safety. Considering that prevention is always superior to treatment, it is essential to pursue global efforts in HBV vaccination.

Continuous evaluation of real-world treatment effectiveness of COVID-19 medicines is required due to the ongoing evolution of SARS-CoV-2 and the possible emergence of resistance. Therefore, this study aimed to analyze, in a retrospective manner, the outcomes in patients hospitalized with COVID-19 during the pandemic waves dominated by Delta and Omicron variants and treated with remdesivir (RDV) (n = 762) in comparison to a demographically and clinically matched group not treated with any antivirals (n = 1060). A logistic regression analysis revealed that RDV treatment was associated with a significantly lower risk of death during both Delta wave (OR = 0.42, 95%CI: 0.29–0.60; p < 0.0001) and Omicron-dominated period (OR = 0.56, 95%CI: 0.35–0.92; p = 0.02). Moreover, RDV-treated groups were characterized by a lower percentage of patients requiring mechanical ventilation, but the difference was not statistically significant. This study is the first real-world evidence that RDV remains effective during the dominance of more pathogenic SARS-CoV-2 variants and those that cause a milder course of the disease, and continues to be an essential element of COVID-19 therapy.

Elimination of hepatitis C virus (HCV) without the need for medical intervention, known as spontaneous clearance (SC), occurs at a significantly lower rate than in the case of hepatitis B virus infection and only in selected individuals, such as reportedly in Keith Richards, a guitarist of The Rolling Stones. The present paper provides an updated narrative review of the research devoted to the phenomenon in order to identify and discuss the demographic, lifestyle-related, clinical, viral genotype-related, and host genetic factors underpinning the SC occurrence. The body of evidence indicates that the likelihood of SC is decreased in older individuals, men, Black people, HIV-coinfected subjects, and intravenous drug and alcohol users. In turn, HBV coinfection and specific polymorphism of the genes encoding interferon lambda 3 (particularly at rs8099917) and interferon lambda 4 (particularly at rs12979860) and HLA genes increase the odds of SC. Numerous other host-specific genetic factors could be implicated in SC, but the evidence is limited only to certain ethnic groups and often does not account for confounding variables. SC of HCV infection is a complex process arising from a combination of various factors, though a genetic component may play a leading role in some cases. Understanding factors influencing the likelihood of this phenomenon justifies better surveillance of high-risk groups, decreasing health inequities in particular ethnic groups, and may guide the development of a prophylactic vaccine, which at present is not available, or novel therapeutic strategies. Further research is needed to elucidate the exact mechanisms underlying SC and to explore potential interventions that could enhance this natural antiviral response.