Global incidence of Clostridioides difficile infection (CDI) in hospitals declined significantly during the COVID-19 pandemic compared with the prepandemic period, Chinese researchers reported late last week in Antimicrobial Resistance & Infection Control.

In a systematic review and meta-analysis, researchers from Hangzhou Medical College examined 16 studies on CDI incidence published from December 2019 through October 2025. Most of the studies were conducted in tertiary hospitals in high-income countries, primarily the United States and Spain. 

While several studies have investigated the pandemic’s impact on CDI, which causes severe diarrhea, the results have been inconsistent, with some studies reporting increases and others showing a marked decline. The study authors say this inconsistency reflects the “complex interplay” of multiple factors during the pandemic.

“Therefore, a comprehensive synthesis of the available evidence is needed to clarify the overall impact of the COVID-19 pandemic on the incidence of CDI,” they wrote.

Overall, the pooled incidence rate of CDI declined from 4.42 per 10,000 patient-days before the pandemic to 3.80 per 10,000 patient-days during the pandemic, representing a 20% decline in CDI incidence (incidence rate ratio, 0.80). 

Further analysis of the studies revealed that the observed reduction in CDI incidence was influenced by the combined effects of changes in infection prevention and control, antimicrobial stewardship, and health care delivery. For example, enhanced hand hygiene, rigorous use of personal protective equipment, and increased environmental cleaning likely disrupted C difficile transmission, while reduced used of fluoroquinolones may have reduced selective pressure on certain C diff strains. Suspension of elective procedures, reduced surgical volume, and shorter hospital stays may have limited patient exposure.

The authors say these factors may have offset countervailing pandemic-related forces that exacerbated the risk of CDI and other health care-associated infections, such as increased use of broad-spectrum antibiotics, resource constraints, and diagnostic challenges.

“The net reduction in CDI incidence observed in this analysis suggests that strengthened foundational infection control practices can offset substantial systemic stressors when consistently and rigorously applied,” they wrote.