What are the odds of getting a serious infection during a hospital stay?
Evidence quality 4.5/5
Eight-dimension review score against the quality rubric . Each dimension scored 1–5.
- D1 Source grounding
- 5/5
- D2 Source authority
- 5/5
- D3 Arithmetic
- 4/5
- D4 Uncertainty
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- D5 Scope
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- D6 Prose
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- D7 Perception honesty
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- D8 Caveat completeness
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Lifetime probability · lifetime, activity-specific
1 in 31
3.2% lifetime chance
Most people underestimate this.
range 1 in 40 to 1 in 20
● your factors — click this risk ▾ to reveal
≈ As likely as
Perceived
There is no standing survey that isolates fear of a healthcare-associated infection, but the category sits in a near-universal blind spot. Patients being wheeled into an acute-care bed tend to model the hospital as a place that neutralises infection risk, not a place that generates it. The iatrogenic framing — that roughly one admission in thirty picks up a bloodstream, surgical-site, urinary, pneumonia, or C. difficile infection that was not present on arrival — is absent from almost every informed- consent conversation and from almost every lay intuition about hospital safety.
Rough estimate: most patients assume the per-admission rate is well under 1 in 1,000
Source: editorial intuition, not polled
Actual
~1 in 31 US hospital patients has at least one HAI on any given day
US acute care hospital patients
Show derivation
The headline figure is per hospital admission, not per adult lifetime. CDC's 2015 point-prevalence survey (the follow-up to Magill et al. 2014) found that about 3% of hospitalised patients had one or more HAIs on any given day, which the agency rounds to "1 in 31 hospital patients." Magill et al. 2014 reported a slightly higher 4.0% prevalence (1 in 25) from 2011 data; the 16% relative decline between the two surveys is real and documented. Likelier reports the more recent 2015 figure as the headline (0.032) with Magill's 0.040 as the upper end of the uncertainty band. Note that point prevalence slightly understates per-admission cumulative incidence — patients admitted briefly and discharged without an HAI are fully represented in the denominator, but a patient who develops an HAI on day 10 is only counted on days when the infection is present — so the "per admission" framing here is a lower bound. The fatal-HAI per-admission figure (~0.005) comes from 72,000 HAI-associated deaths against roughly 14.4 million annual US acute-care admissions with HAI exposure windows, which is the second regional_breakdown row below.
Caveats: The headline point-prevalence figure ("1 in 31") is a snapshot, not a cumulative…
The headline point-prevalence figure ("1 in 31") is a snapshot, not a cumulative per-admission risk, and slightly understates the probability that a given admission includes an HAI somewhere along its timeline. The WHO per-admission figures (7/100 high-income, 15/100 LMIC) are the cleaner per-admission numbers and are closer to what a patient being admitted should mentally budget. The distribution is also radically non-uniform: a 48-hour observation admission on a general ward is a very different risk than a three-week ICU stay with a ventilator and two central lines, which is what the personal_factor_multipliers above are trying to capture. Finally, the US figure has improved meaningfully since 2011 (a 16% relative decline between Magill 2014 and CDC 2015, with further gains through 2024 in CAUTI and C. difficile), so the headline is a trailing indicator — the 2026 figure is probably somewhat lower than 1 in 31, though no current survey cleanly replaces the 2015 baseline.
Regional breakdown
The headline figure averages across very different populations. Here’s how the probability varies by geography or context:
| Region / context | Lifetime probability | Notes |
|---|---|---|
| Any HAI per US admission | 1 in 31 |
CDC 2015 point-prevalence figure — "1 in 31 hospital patients." Magill 2014 put the equivalent 2011 number at 4.0%. |
| Fatal HAI per US admission | 1 in 200 |
~72,000 HAI-associated in-hospital deaths divided across roughly 14.4M at-risk acute-care admissions. Order-of-magnitude figure. |
| Any HAI per LMIC admission | 1 in 8.3 |
WHO 2022 global report: 15 per 100 admissions in low- and middle-income countries acquire at least one HAI, roughly double the 7/100 high-income country rate. Point estimate rounded to 0.12. |
| ICU admission, any HAI | 1 in 6.7 |
WHO reports overall ICU HAI incidence around 30% globally, with an order of magnitude more variation across countries; the 0.15 figure here is closer to the high-income ICU baseline (Magill 2014 reported ICU HAI point prevalence several multiples higher than ward averages). Use 0.30 as the LMIC ICU ceiling. |
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The numbers land in a place most patients do not expect. CDC’s 2015 point-prevalence survey of US acute-care hospitals found that about 1 in 31 hospitalised patients has at least one healthcare-associated infection on any given day, translating to roughly 687,000 HAIs and 72,000 HAI-associated in-hospital deaths per year. The Magill et al. 2014 NEJM survey, using 2011 data, put the equivalent prevalence at 4.0% (about 1 in 25) before the post-2011 decline. Divide the 72,000 deaths across the at-risk admissions window and the per-admission fatal-HAI probability lands somewhere around 1 in 200. Stacked against the per-flight fatality rate of roughly 1 in 13.7 million, or the lifetime lightning-strike rate of roughly 1 in 1.2 million, a hospital admission is one of the highest per-exposure iatrogenic hazards a typical adult will encounter.
What’s in the category is worth seeing up close. Magill reported pneumonia and surgical-site infections tied as the two largest buckets (21.8% each), followed by gastrointestinal infections (17.1%), with C. difficile as the single most common pathogen at 12.1% of all HAIs. Catheter-associated urinary tract infections and central line-associated bloodstream infections round out the top five. These categories are not evenly distributed across hospital geography: the ICU baseline is several multiples above the ward, ventilator-days drive the pneumonia curve almost linearly, and central lines and urinary catheters create the device-associated infections whose rates have fallen the most since the mid-2000s checklist era. The two biggest levers, in every serious review of the literature, are antibiotic stewardship (to contain C. difficile and multidrug-resistant organisms) and barrier precautions plus hand hygiene (to contain everything else).
The global picture is the part that is genuinely underrated. WHO’s 2022 Global Report on Infection Prevention and Control found that 7 per 100 admissions in high-income countries and 15 per 100 admissions in low- and middle-income countries acquire at least one HAI during their stay, with roughly 1 in 10 affected patients dying of the infection. ICU rates in low- and middle-income countries run 2 to 20 times higher than in wealthy-country ICUs. Put plainly: a patient admitted to an ICU in a resource-limited setting faces an HAI probability that approaches a coin flip. For a US reader the headline 1-in-31 figure is the right baseline, with ICU admission, ventilation, central lines, and stays past a week each adding multiplicative risk on top of it. For a global reader the LMIC figures are the ones that dominate the aggregate burden, and they are the least-discussed large public-health statistic on this site.
Claim ledger
Every number below is what each source reported, with the verbatim quote we relied on and how we arrived at our figure. Click any link to verify directly.
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[1] New England Journal of Medicine / Magill SS, Edwards JR, Bamberg W, et al. — Multistate Point-Prevalence Survey of Health Care-Associated Infections
Multistate Point-Prevalence Survey of Health Care-Associated Infections- Statistic
4.0% point prevalence of HAI among hospitalised patients (95% CI 3.7-4.4); estimated 648,000 patients with 721,800 HAIs in US acute care hospitals in 2011- Excerpt
“"Of 11,282 patients, 452 had 1 or more health care-associated infections (4.0%; 95% confidence interval, 3.7 to 4.4)." "We estimated that there were 648,000 patients with 721,800 health care-associated infections in U.S. acute care hospitals in 2011." ”
- Source data from
- 2014-03-27
- Accessed
- 2026-04-11 · archived copy
- Calculation
- Magill et al. is the canonical US HAI point-prevalence study and the origin of the widely-cited "1 in 25 hospitalised patients has an HAI" figure. Pneumonia (21.8%) and surgical-site infections (21.8%) were the two most common categories, followed by gastrointestinal infections (17.1%, dominated by C. difficile, which was the single most common pathogen at 12.1% of all HAIs). The 4.0% point- prevalence figure anchors the upper end of Likelier's uncertainty band; the 2015 CDC follow-up survey (3%, "1 in 31") is used as the headline because it is more recent and reflects a genuine decline in HAI rates post-2011.
- Independence
- Methodologically upstream of CDC's 2015 survey: both are point-prevalence surveys run through the Emerging Infections Program using the same case definitions, so the two should be read as one dataset compared against itself across years rather than as two fully independent estimates. WHO's global report is independent of both and is the cleaner cross-check.
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[2] Centers for Disease Control and Prevention (CDC) — Healthcare-Associated Infections (HAIs) Data
Healthcare-Associated Infections (HAIs) Data- Statistic
~1 in 31 US hospital patients has at least one HAI on any given day; ~687,000 HAIs and ~72,000 HAI-associated in-hospital deaths in 2015- Excerpt
“"On any given day, about one in 31 hospital patients has at least one healthcare- associated infection." "There were an estimated 687,000 HAIs in U.S. acute care hospitals in 2015." "About 72,000 hospital patients with HAIs died during their hospitalizations." ”
- Source data from
- 2015-01-01
- Accessed
- 2026-04-11 · archived copy
- Calculation
- CDC's 2015 HAI Hospital Prevalence Survey is the direct successor to Magill et al. 2014 and is the source of the headline "1 in 31" figure used throughout this entry. The 72,000 annual HAI-associated in-hospital deaths, divided across roughly ~14.4 million at-risk US acute-care admissions, gives a per-admission fatal-HAI rate of roughly 0.5% — the second regional_breakdown row. The CDC also notes a 16% relative decline in HAI prevalence between 2011 (Magill) and 2015 and further decreases between 2023 and 2024 across CAUTI and C. difficile infections, which is why the 2011 4.0% figure is the ceiling of the uncertainty band rather than the headline.
- Independence
- CDC's 2015 survey shares methodology with Magill et al. 2014 (same point- prevalence design, same Emerging Infections Program network). Treat as a time- series update of the same dataset, not a fully independent estimate.
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[3] World Health Organization — WHO launches first ever global report on infection prevention and control
WHO launches first ever global report on infection prevention and control- Statistic
7 per 100 patients in high-income countries and 15 per 100 patients in low- and middle-income countries acquire at least one HAI during hospital stay; ~1 in 10 affected patients dies- Excerpt
“"out of every 100 patients in acute-care hospitals, seven patients in high-income countries and 15 patients in low- and middle-income countries will acquire at least one health care-associated infection." "On average, 1 in every 10 affected patients will die from their HAI." ”
- Source data from
- 2022-05-06
- Accessed
- 2026-04-11 · archived copy
- Calculation
- WHO's 2022 Global Report on Infection Prevention and Control gives the cleanest cross-country comparison. The 7%/15% figures are per admission (cumulative incidence over the stay, not point prevalence), which is why they are higher than the US point-prevalence number used as the headline: a 7% per-admission cumulative incidence in a high-income system is consistent with a ~3% point prevalence on any given day once you account for admission length and infection-onset timing. The 10% HAI case-fatality rate, applied to the WHO high-income figure, gives ~0.7% per-admission fatal-HAI probability, bracketing the CDC-derived 0.5% figure. The 15% LMIC figure is the source of the regional_breakdown row for LMIC admissions below.
- Independence
- Fully independent of Magill and CDC: WHO synthesises hundreds of national surveys across dozens of countries, most of which are not part of the US Emerging Infections Program network. This is the strongest cross-check in the entry.