- Design
- Systematic review and random-effects meta-analysis
- Population
- Studies testing asymptomatic people for MPXV in non-endemic regions, 2022–2024
- Primary outcome
- Pooled prevalence of asymptomatic MPXV detection
- Effect
- 1.0% (95% prediction interval 0.1%–11.2%)
A meta-analysis pooled studies published from May 2022 to September 2024 that tested people without symptoms for monkeypox virus in regions where it is not endemic. The pooled prevalence of asymptomatic detection was 1.0%, with a 95% prediction interval from 0.1% to 11.2%. Results were similar across regions and study designs.
The headline is reassuring for infection control: in most settings, very few people without lesions carry detectable virus. But the prediction interval is wide, meaning some populations — such as those with high-risk sexual networks — may have much higher rates. The studies measured viral DNA, not infectiousness, so whether asymptomatic carriers transmit remains unknown.
For clinicians, the practical approach is unchanged: test people with compatible lesions, and in contacts monitor for symptoms rather than test routinely.
- Asymptomatic mpox detection was rare overall, but much higher prevalence is possible in specific high-risk groups.
- A positive PCR without symptoms does not establish infectiousness.
- Advise contacts to watch for fever, lymphadenopathy and rash for 21 days.
- Test any new anogenital or mucosal lesion in a person with relevant exposure.
Why it matters
It supports symptom-based testing rather than broad screening of contacts.
Don't overread it
Detection of viral DNA is not proof of transmissibility; the study did not assess spread from asymptomatic people.
The statistics, in plain English
A prediction interval of 0.1% to 11.2% describes the range expected in a new study population. It is much wider than the pooled estimate suggests, because the studies varied a great deal.
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