Risk
Could plague cause a new pandemic? What experts say
Quick answer
- The risk of plague causing a pandemic is considered low by experts.
- The disease does not spread as easily as respiratory viruses; only the pneumonic form passes between people, and it requires close contact.
- Plague is treatable with antibiotics, which completely changes the picture compared with historical pandemics.
- Concerning scenarios involve pneumonic plague in dense urban areas with late diagnosis — and even those are contained with surveillance.
Could plague become a pandemic?
In most experts' assessment, the risk of plague causing a pandemic similar to COVID-19 is low. That does not mean zero risk — plague has caused pandemics in the past — but the conditions have changed radically.
Why it does not spread like a respiratory virus
| Aspect | Pneumonic plague | Highly transmissible respiratory viruses |
|---|---|---|
| Person-to-person spread | Only the pneumonic form | Frequent |
| Type of contact | Close and prolonged | Can occur over distance |
| Spread by asymptomatic people | No | Possible |
| Treatment | Effective antibiotics | Varies; not always specific |
| Containment | Isolation + contact prophylaxis | Depends on vaccines and population measures |
Two factors sharply reduce transmissibility: plague only spreads between people in the pneumonic form, and even then it requires proximity. People without symptoms do not transmit it.
Why antibiotics change everything
In historical pandemics there was no specific treatment. Today, plague is susceptible to common antibiotics, and contacts can receive prophylaxis. Rapid diagnosis combined with early treatment interrupts transmission chains before they grow.
The bottleneck is time, not the drug
What worsens scenarios is delayed diagnosis and lack of access to treatment — not the absence of effective antibiotics.
Which scenarios are concerning
The scenario of greatest concern is pneumonic plague in a dense urban area with delayed diagnosis. That is what happened in Madagascar in 2017, when a pneumonic plague outbreak produced around 2,300 cases and more than 200 deaths — and was contained with a rapid response.
The lesson from that episode is that containment depends on surveillance, agile laboratory diagnosis, isolation and contact chemoprophylaxis. Where those are lacking, case numbers can rise quickly.
And the Irkutsk case (2026)?
The incident at the Irkutsk Anti-Plague Institute in Siberia was an isolated case of probable laboratory infection. Russian authorities said there was no outbreak and that contacts tested negative. Experts cited in the media assessed the risk of spread as low.
This illustrates the current pattern: sporadic cases and occupational accidents happen, but they are contained by surveillance systems — they do not automatically evolve into outbreaks or pandemics.
Frequently asked questions
Could plague cause a new pandemic?
The risk is considered low. Person-to-person transmission occurs only in the pneumonic form and requires close contact, and the disease is treatable with antibiotics.
Why doesn't plague spread like COVID-19?
Because it does not spread efficiently through the air over distance, it is not transmitted by people without symptoms, and it depends on the pneumonic form to pass between humans.
Have there been urban pneumonic plague outbreaks?
Yes. Madagascar had a pneumonic plague outbreak in 2017 with around 2,300 cases and more than 200 deaths, contained with a rapid response.
Does the Irkutsk case change global risk?
Not significantly. It is an isolated case of probable laboratory origin, with no confirmed community outbreak.
Sources
Medical review
Review by a licensed health professional is being arranged. This educational content is based on reference sources (WHO, CDC and medical literature) and does not replace evaluation, diagnosis or treatment by a health professional.
How this content was produced
- Who
- Produced by the Equipe editorial do Peste.com.br, the editorial team responsible for gathering, verifying and classifying public information about plague (Yersinia pestis).
- How
- Information is compiled from official and scientific sources (WHO, CDC and national health authorities) and from recognised news outlets. Every statement is classified as confirmed, reported or unconfirmed, and each article lists its sources.
- Why
- To offer clear, source-based information in Portuguese about plague and to separate verified fact from rumour. This content is educational and does not replace medical advice.
- Medical review
- Review by a licensed health professional is being arranged; no credential is claimed until a real professional is credited.
- Last review
See our sources and methodology and the editorial team.A revisão por profissional de saúde habilitado está em processo de credenciamento. Assim que concluída, o nome e o registro serão informados nesta página e nos dados estruturados.