Circulating currency notes in Africa show 79.3% bacterial contamination prevalenceHigh Rates of Bacterial Contamination Found on African Currency

Frontiers in Medicine Published October 19, 2026 DOI ↗ Editorial oversight: Dr. Sofia Müller, MD · Lifespan & Whole-Person Care

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Key Takeaway

Consider hand hygiene after handling currency given high pooled bacterial contamination estimates.

This is a meta-analysis pooling data from 12 studies on bacterial contamination of circulating currency notes in African countries, covering 2,003 notes. It reports prevalence estimates rather than clinical outcomes, and no comparator or follow-up data are described.

The pooled overall bacterial contamination prevalence was 79.3% (95% CI: 60.9 to 90.4%). Organism-specific estimates were 31.2% for Staphylococcus aureus (95% CI: 24.7 to 38.4%) and 24.0% for Escherichia coli (95% CI: 17.8 to 31.5%). The analysis also describes multidrug-resistant, extensively drug-resistant, and pan drug-resistant strains among the isolates.

The authors frame currency as a possible environmental reservoir for clinically important and antimicrobial-resistant bacterial species. This is an association between currency and contamination; the analysis does not establish a direct causal link to specific human infections. Heterogeneity across the included studies, certainty of the pooled estimates, and funding or conflicts of interest were not reported in the source data.

For practice, the findings support attention to hand hygiene after handling currency and to currency management practices as plausible steps to reduce exposure risk. The prevalence figures should be interpreted as pooled observational estimates, not as evidence of transmission or clinical harm.

A review of 12 different studies looked at the cleanliness of currency notes circulating in various African countries. The researchers analyzed over 2,000 notes to see how many carried bacteria. They found that 79.3% of the notes were contaminated with some form of bacteria.

Among the bacteria found, the study identified specific types like Staphylococcus aureus and Escherichia coli. These types of bacteria are often important in medical settings. The study also found that some of these bacteria were resistant to multiple drugs, which can make them harder to treat with standard medicine.

Because money is handled by many people every day, it can act as a place where germs live and spread. While this study shows a link between currency and bacteria, it does not prove that the money directly causes specific infections in people. However, the findings suggest that better hand hygiene and better management of money could help reduce the risk of spreading germs.

What this means for you:

High levels of bacterial contamination on currency suggest a need for better hand hygiene and money management.

Common questions

How much bacteria was found on the money?

The study found that 79.3% of the currency notes were contaminated with bacteria. This high percentage suggests that money can be a place where bacteria live and spread in the environment.

What specific types of bacteria were found?

The analysis identified specific types of bacteria, including Staphylococcus aureus at a 31.2% prevalence and Escherichia coli at a 24.0% prevalence. Some of these were found to be resistant to multiple drugs.

Does this mean the money causes infections?

The study shows a link between currency and bacterial contamination, but it does not establish a direct causal link to specific human infections. It suggests that better hand hygiene may help reduce risks.

Study Details

Study typeMeta analysis

EvidenceLevel 1

PublishedOct 2026

View Original Abstract ↓

BackgroundCirculating currency is among the most frequently handled objects in daily life and may facilitate microbial transfer between individuals, food products and environmental surfaces. Although bacterial contamination of currency has been documented across Africa, the overall burden and epidemiological significance of this contamination have not been systematically quantified. This systematic review and meta-analysis synthesized available evidence on bacterial contamination of circulating currency in Africa.MethodsPubMed, Scopus, Web of Science, African Journals Online (AJOL), Google Scholar were systematically searched. Studies investigating bacterial contamination of circulating currency notes in African countries were eligible. Random-effects meta-analysis was performed to estimate pooled contamination prevalence and organism-specific prevalence while narrative synthesis was used for outcomes unsuitable for quantitative pooling.ResultsForty-six studies met the inclusion criteria and contributed to the systematic and narrative synthesis. Of these, 12 studies involving 2,003 currency notes provided sufficient comparable data for the meta-analysis of overall bacterial contamination prevalence. The pooled bacterial contamination prevalence was 79.3% (95% CI: 60.9–90.4%). Organism-specific analyses showed that Staphylococcus aureus accounted for 31.2% (95% CI: 24.7–38.4%) and Escherichia coli for 24.0% (95% CI: 17.8–31.5%) of bacterial isolates recovered from contaminated currency. Narrative evidence additionally identified Klebsiella, Salmonella, Pseudomonas, Proteus, and Shigella species among frequently reported contaminants. Several studies also documented multidrug-resistant, extensively drug-resistant, and pan drug-resistant bacterial strains. Lower-denomination and physically worn banknotes exhibited higher contamination burdens than higher-denomination or newer notes.ConclusionBacterial contamination of circulating currency is highly prevalent across African settings and includes clinically important and antimicrobial-resistant bacterial species. These findings suggest that circulating currency may serve as an underrecognized environmental reservoir and a potential interface for microbial exchange between human, food, and environmental systems. From a One Health perspective, strengthening hand hygiene, discouraging simultaneous handling of food and money and improving currency management may help reduce contamination risks and limit microbial dissemination within communities.

Circulating currency notes in Africa show 79.3% bacterial contamination prevalenceHigh Rates of Bacterial Contamination Found on African Currency

Common questions

Study Details

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Circulating currency notes in Africa show 79.3% bacterial contamination prevalenceHigh Rates of Bacterial Contamination Found on African Currency

Common questions

Study Details

Health warnings on social media perceived as more effective than neutral messages in teens

Social Media Warnings May Discourage Use in Teens

Clinical research that matters. Delivered to your inbox.

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