TOPLINE

Recent SARS-CoV-2 infection more than doubled the risk of death among adults with Staphylococcus aureus bacteremia (SAB) during 2020-2022, with hospital-onset (HO) cases reaching mortality rates of 75%. Mortality rates rose by 33% for HO methicillin-resistant S. aureus (MRSA) cases and by 41% for HO methicillin-susceptible S aureus (MSSA) cases from 2019 through 2021.

METHODOLOGY

• Researchers analyzed active, laboratory- and population-based surveillance data from 20 counties across seven US states to examine annual trends in mortality rates among adult patients with SAB during 2005-2022 both before and during the COVID-19 pandemic.
• A total of 72,920 SAB cases and 15,114 deaths were included, comprising 54,043 MRSA cases with 11,692 deaths and 18,877 MSSA cases with 3,422 deaths.
• Cases were categorized by epidemiologic class: hospital-onset (HO) if incident culture was collected ≥3 days after hospitalization; healthcare-associated community-onset (HACO) if collected in outpatient setting or <3 days after hospitalization from patients with healthcare risk factors; or community-associated (CA) if none of these criteria were met.
• Recent SARS-CoV-2 infection was defined as a positive viral test (molecular assay or antigen) ≤30 days before or on the incident SAB culture date, ascertained through medical record review, state reportable disease surveillance systems, and COVID hospitalization surveillance records.
• Researchers evaluated associations between recent SARS-CoV-2 infection and mortality adjusting for demographics, comorbidities, and other risk factors. The study outcome was all-cause mortality within 30 days of incident culture.

TAKEAWAY

• Overall SAB mortality was 21%. Recent SARS-CoV-2 infection was significantly associated with 30-day all-cause mortality (adjusted hazard ratios (HRs) ranged from 1.9 [95% CI, 1.5-2.3] for HACO MRSA cases to 3.0 [95% CI, 2.4-3.7] for HO MSSA cases).
• Among HO cases with recent SARS-CoV-2 infection, annual mortality rates reached 75% for MRSA cases in 2020 and 64% for MSSA cases in 2021, approximately 2–3 times greater than rates for cases without recent SARS-CoV-2 infection. Overall, MRSA HO mortality rates increased by 33% and MSSA HO mortality rates increased by 41% from 2019 to 2021.
• MRSA CA mortality rates increased by 49% from 2019 to 2021, while MSSA CA mortality rates remained stable at 14%t to 17% during 2019 to 2022. The direct effect of recent SARS-CoV-2 infection was about 2.1 to 2.9 times higher, whereas the overall effect of the pandemic on SAB mortality was modest but significant (mortality rate ratio, 1.2).
• Pre-pandemic MRSA mortality rates ranged from 28%-37% (HO), 19%-23% (HACO), and 11%-17% (CA) during 2005-2019, while pre-pandemic MSSA mortality rates ranged from 25%-28% (HO), 15%-18% (HACO), and 12%-16% (CA) during 2016-2019.

IN PRACTICE

“These findings emphasize the importance of infection prevention in patients hospitalized with SARS CoV-2 infection and could lend support for greater infection prevention measures among patients early in a similar respiratory virus pandemic to reduce secondary SAB and ultimately prevent deaths,” the study authors concluded.

SOURCE

The study was led by Carly Adams, Centers for Disease Control and Prevention in Atlanta. It was published online  on August 21, 2026, in Open Forum Infectious Diseases.

LIMITATIONS

The analysis could not distinguish deaths due to SAB from deaths due to other causes, though a 30-day follow-up time was used to minimize inclusion of non-SAB deaths. Researchers could not differentiate between symptomatic COVID and asymptomatic SARS-CoV-2 infection or between current and recent infection. Additionally, changes in SARS-CoV-2 testing practices over time may have affected infection detection rates. 

DISCLOSURES

The study was supported by cooperative agreements through the CDC Emerging Infections Program. One author declared serving on the Board of the Council of State and Territorial Epidemiologists and being an Associate Editor for the American Academy of Pediatrics Report of the Committee on Infectious Diseases. Additional author disclosures are reported in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.