Recent COVID-19 Tripled Some Bacteremia Mortality Rates

STAPHYLOCOCCUS aureus bacteremia mortality rose during the COVID-19 pandemic, particularly among hospital-onset cases with recent infection.

A population-based analysis of 20 U.S. counties found that 30-day mortality increased substantially in several bacteremia groups from 2019 through 2021. Recent SARS-CoV-2 infection was also independently associated with a markedly higher hazard of death.

S. aureus Bacteremia Mortality Increased

Researchers analyzed active laboratory and population surveillance data collected across seven states between 2005 and 2022. The analysis included adults with methicillin-resistant S. aureus (MRSA) or methicillin-susceptible S. aureus (MSSA) bacteremia.

Cases were classified as hospital-onset, healthcare-associated community-onset, or community-associated. Medical records were linked with state vital statistics to identify deaths within 30 days of the incident culture.

Overall, mortality among people with S. aureus bacteremia was 21%. Annual mortality rates were generally stable before the pandemic but increased considerably in selected groups between 2019 and 2021.

Mortality rose by 33% among hospital-onset MRSA cases and by 41% among hospital-onset MSSA cases. Community-associated MRSA cases experienced a 49% increase. Similar increases were not observed among healthcare-associated community-onset cases or community-associated MSSA cases.

Recent COVID-19 Intensified Mortality

Recent SARS-CoV-2 infection was defined as a positive test within 30 days before the incident blood culture. Among people with hospital-onset bacteremia and recent infection, annual mortality reached as high as 75%.

After adjustment for demographic characteristics and other risk factors, recent SARS-CoV-2 infection remained significantly associated with death across all epidemiologic and methicillin susceptibility categories.

Adjusted hazard ratios ranged from 1.9 among healthcare-associated community-onset MRSA cases to 3.0 among hospital-onset MSSA cases. People with hospital-onset MSSA bacteremia and recent COVID-19 therefore had three times the adjusted hazard of death compared with those without recent infection.

Infection Prevention Remains Critical

The findings identify recent SARS-CoV-2 infection as an important mortality factor among adults with S. aureus bacteremia during 2020 through 2022. They also demonstrate how a respiratory pandemic may compound poor outcomes from serious bloodstream infections.

The findings support strengthening infection prevention measures during future respiratory pandemics, particularly for hospitalized people vulnerable to secondary bacterial infections.

Reference
Adams C et al. Trends in mortality and the effects of the COVID-19 pandemic on mortality among adult patients with Staphylococcus aureus bacteremia, 20 US counties, 2005–2022. Open Forum Infect Dis. 2026;doi:10.1093/ofid/ofag524.

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