Latest COVID-19 research looks at plasma antigen levels, oral antivirals, HAIs

Plasma antigen levels of SARS-CoV-2 were associated with severity of illness among hospitalized COVID-19 patients, according to a study published by Annals of Internal Medicine on Aug. 30. Researchers used samples from 2,540 patients in 10 countries, finding plasma antigen below the level of quantification in 5% of participants at enrollment and 1,000 ng/L or greater in 57%. The mean plasma antigen level was threefold higher in patients requiring noninvasive ventilation or high-flow nasal cannula compared to room air and sixfold higher in those who lacked antispike antibodies. A plasma antigen level of 1,000 ng/L or greater was associated with higher risk of worsened pulmonary status at day 5 (odds ratio, 5.06; 95% CI, 3.41 to 7.50) and longer time to hospital discharge (median, 7 vs. 4 days). “These data support a potential role of ongoing viral replication in the pathogenesis of SARS-CoV-2 in hospitalized patients,” concluded the study authors, who suggested that plasma antigen levels might eventually be a method for identifying patients more likely to benefit from antiviral therapy. “Plasma antigen is a practical and clinically meaningful biomarker for hospitalized patients with COVID-19,” they said.

Molnupiravir and nirmatrelvir-ritonavir showed benefit in hospitalized patients with mild-to-moderate COVID-19 in a retrospective study published by The Lancet on Aug. 24. It included patients in Hong Kong hospitalized during the omicron BA.2 wave but not requiring supplemental oxygen at baseline: 1,856 who received molnupiravir, 890 who received nirmatrelvir-ritonavir, and equal numbers of matched controls. All-cause mortality was lower in molnupiravir recipients (19.98 vs. 38.07 events per 10,000 person-days, P<0.0001) and in nirmatrelvir-ritonavir recipients (10.28 vs. 26.47 per 10,000 person-days, P<0.0001) compared to their controls. Oral antiviral recipients also had lower risks of a composite disease progression outcome and of need for oxygen therapy. The study authors concluded that initiation of these treatments in hospitalized patients with mild-to-moderate COVID-19 showed substantial clinical benefit and that their results support the early use of oral antivirals in this population of patients. However, they offered some important caveats: “Results of our subgroup analyses suggested a possible lack of significant benefit in younger patients (aged ≤65 years) and those who had been fully vaccinated, which would support prioritising the prescription of oral antivirals to older people and those not adequately vaccinated, who are also likely to be at increased risk of progression to severe COVID-19.” Similarly, a study published by the New England Journal of Medicine on Aug. 24 found benefit from nirmatrelvir in patients 65 years and older but not younger patients.

Infections from central lines and ventilators increased during the pandemic, particularly in smaller hospitals, according to a study published by Clinical Infectious Diseases on Aug. 23. The retrospective study used hospital-acquired infection rates from 53 U.S. hospitals from Jan. 1, 2018, to March 31, 2021. Central-line-associated bloodstream infections and ventilator-associated events increased by 24% and 34%, respectively, over the pandemic, while Clostridioides difficile infections increased by 4.2% per month. Stratification by hospital characteristics found that the trends were more significant in smaller and community hospitals. “Future efforts should focus on better understanding challenges faced by community hospitals, strengthening infection prevention infrastructure, and expanding the ID workforce, particularly to community hospitals,” concluded the authors, who also noted that expansion of tele-ID and remote infection prevention services would help but should be accompanied by appropriate resources, infrastructure, and reimbursement models.