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The Next Pandemic May Already Be Here

From Nipah and West Nile to H5N1 and antimicrobial resistance — thirty years of warnings, and the lessons we keep relearning.

Cyberdoc — writing on medicine since 1995

What’s next?

In June 1999, after Malaysia had been through enterovirus, haze and the encephalitis outbreak that would become known as Nipah, I wrote a Cybermed piece with a rather ominous title: “Enterovirus, Haze, Nipah and Dioxin. What’s Next?” The old Cybermed archive is still online — a useful reminder that emerging infections were preoccupying us long before COVID-19. Sources: Cybermed-Enews Archive 1997–2003.

A few months later another infectious-disease story was unfolding half a world away. Birds were dying around New York City and people were developing encephalitis. The cause was eventually identified as West Nile virus. My West Nile Fever page went up on 11 October 1999 and remained updated for years as the virus established itself in North America. Sources: West Nile Fever · CDC MMWR.

Neither Nipah nor West Nile became a global pandemic. But both contained lessons that seem remarkably familiar today. Since then we have lived through SARS, H1N1 influenza and COVID-19. H5N1 avian influenza has never really gone away. Nipah continues to spill over into humans. Antimicrobial resistance is steadily eroding the effectiveness of medicines on which modern healthcare depends. Sources: WHO · FAO/WHO/WOAH · WHO.

The next pandemic may already be here — not because another COVID is necessarily imminent, but because the biological ingredients of the next major health emergency may already be circulating around us.

The more useful question is not whether we can correctly predict the next pathogen. It is whether we have learned enough to recognise a dangerous change early — and whether our systems can respond before an outbreak becomes a crisis. Sources: WHO.

Thirty years of warnings

Look backwards and the pattern is striking. H5N1 infected humans in Hong Kong in 1997. Malaysia’s 1998–99 encephalitis outbreak led to the identification of Nipah virus. West Nile appeared in New York in 1999. SARS followed in 2003, pandemic H1N1 in 2009 and COVID-19 in 2020. Each event was different, but each showed microbes exploiting opportunities created by animal reservoirs, ecology, travel, healthcare settings and human behaviour. Sources: WHO · CDC MMWR · CDC.

Each warning taught something different: Nipah about spillover at the animal–human interface, West Nile about ecological surveillance, H5N1 about watching for a change in transmission, SARS about healthcare amplification, COVID about system resilience, and AMR about threats that advance without an obvious starting gun.

Nipah — Malaysia’s warning to the world

For Malaysians of my generation, Nipah is not an abstract example from an epidemiology textbook. We watched it happen. The virus was first identified during the 1998 outbreak among pig farmers in Malaysia; fruit bats of the Pteropodidae family are its natural hosts, and transmission can occur from animals to humans, through contaminated food and directly between people. The discovery paper — documenting a previously undescribed paramyxovirus in three fatal cases — was published in The Lancet in October 1999. Sources: WHO · Chua KB et al., “Fatal encephalitis due to Nipah virus among pig-farmers in Malaysia,” Lancet 354(9186):1257–1259 (1999), DOI 10.1016/S0140-6736(99)04299-3 · Lam SK & Chua KB, “Nipah Virus Encephalitis Outbreak in Malaysia,” Clin Infect Dis 34(Suppl 2):S48–S51 (2002), DOI 10.1086/338818 · Naidoo T et al., “A systematic review of Nipah virus disease epidemiological parameters, outbreaks, and mathematical models,” Lancet Infect Dis (14 July 2026), DOI 10.1016/S1473-3099(26)00239-2.

WHO estimates a case-fatality rate of roughly 40–75%, varying by outbreak. Malaysia and Singapore have reported no new outbreaks since 1999, but Bangladesh has experienced outbreaks almost every year since 2001 and India continues to report periodic outbreaks, including in 2026. Sources: WHO.

Nipah’s enduring lesson is not that it is destined to become the next pandemic. It is that a virus can move across the animal–human interface in different ways, and that agriculture, ecology, behaviour and health systems are part of the same epidemiological story. Sources: WHO · WHO.

West Nile — when an old virus finds a new home

West Nile taught a different lesson. The virus was not new. What was new was where it appeared. In August 1999 an infectious-disease physician in Queens alerted the New York City Department of Health to two patients with encephalitis. The investigation ultimately identified a West Nile-like virus in human, avian and mosquito samples. Sources: CDC MMWR.

My own West Nile page followed that story from October 1999 onward. It remains an interesting historical record because the warning did not come from humans alone: birds, mosquitoes and veterinary surveillance became part of understanding the outbreak. Sources: West Nile Fever.

Sometimes the first warning comes from a patient. Sometimes from a pig or a bat. And sometimes it comes from a dead crow.

That is one reason the modern One Health approach matters. WHO explicitly includes zoonotic and vector-borne diseases such as avian influenza and West Nile virus within a framework that links human, animal and ecosystem health. Sources: WHO.

H5N1 — the warning that never went away

Few infectious threats illustrate uncertainty better than H5N1. Avian influenza has been watched for decades, yet an H5N1 human pandemic has not occurred. That distinction matters. Animal circulation is not a pandemic; sporadic animal-to-human infection is not a pandemic; even small clusters do not by themselves establish sustained human transmission. Sources: FAO/WHO/WOAH.

In its May 2026 joint assessment, FAO, WHO and WOAH judged the global public-health risk from currently circulating highly pathogenic avian influenza A(H5) viruses to be low, while rating risk for occupationally or frequently exposed people as low to moderate depending on local conditions. The agencies also warned that animal transmission continues, sporadic human infections are expected, and the assessment could change rapidly if epidemiological or virological evidence changes. Sources: FAO/WHO/WOAH.

That is the sober position H5N1 requires: neither “the next pandemic has begun” nor “we have heard this before, so ignore it.” The correct response is surveillance — especially surveillance capable of detecting a change in transmission. Sources: FAO/WHO/WOAH.

SARS — the rehearsal

SARS in 2003 provided another kind of warning. Healthcare facilities became major amplifiers of transmission. CDC’s post-SARS guidance emphasised that undetected cases could drive rapid spread, that infection-control systems needed to be developed before an outbreak, and that communication and information management were central to an effective response. Sources: CDC.

SARS was contained. But its lessons were remarkably close to the lessons we would discuss again during COVID-19: early recognition, isolation, infection prevention, contact tracing, adequate staffing and supplies, and rapid information sharing. Sources: CDC.

If SARS was the rehearsal, why did COVID-19 still find so many systems unprepared?

COVID-19 — science delivered; systems struggled

COVID-19 demonstrated what modern biomedical science can achieve under extraordinary pressure: rapid pathogen identification and sequencing, diagnostics, large clinical trials, therapeutics and vaccines developed at unprecedented speed. But it also exposed shortages, fragile supply chains, workforce strain, unequal access, misinformation and profound problems of public trust. Sources: WHO.

WHO’s February 2026 answer to the question “Is the world better prepared?” was deliberately balanced: “yes and no.” The world has made concrete gains — including the WHO Pandemic Agreement adopted in 2025, strengthened International Health Regulations and expanded preparedness mechanisms — but WHO also describes progress as fragile and uneven. Sources: WHO.

Perhaps the fairest COVID lesson is therefore not that science failed. Science delivered extraordinary tools. The harder question is whether institutions, politics, financing and public trust can use those tools effectively when the next emergency arrives. Sources: WHO · Sachs JD et al., “The Lancet Commission on lessons for the future from the COVID-19 pandemic,” Lancet 400(10359):1224–1280 (2022), DOI 10.1016/S0140-6736(22)01585-9.

The pandemic that doesn’t need a virus

There is another possibility — one that does not fit the conventional picture of a pandemic at all. The greatest infectious threat may never produce the dramatic moment when borders close and television screens display case counters. Antimicrobial resistance is already advancing without a single “day one.” Sources: WHO.

WHO’s July 2026 fact sheet estimates that bacterial AMR was associated with more than 4.7 million deaths globally in 2021. Approximately one in six laboratory-confirmed bacterial infections worldwide was resistant to antibiotics in 2023. Misuse and overuse of antimicrobials are major drivers, while the pipeline for new medicines remains thin. Sources: WHO.

COVID spread across the world in months. Antimicrobial resistance has been spreading across the world for decades.

The consequences are less cinematic but potentially profound: infections become harder to treat, hospital stays and costs rise, and surgery, chemotherapy, transplantation and intensive care become riskier when dependable antimicrobial treatment can no longer be assumed. Sources: WHO.

One Health — one problem

Put Nipah, West Nile, H5N1 and antimicrobial resistance beside one another and the traditional boundaries between human medicine, veterinary medicine and environmental health begin to look artificial. WHO notes that more than 60% of reported emerging infectious diseases come from animals and identifies agriculture, animal trade, urbanisation, climate change, habitat fragmentation and encroachment into wild areas among the pressures creating new opportunities for disease emergence and spread. A foundational analysis of 335 emerging infectious-disease events between 1940 and 2004 found that 60.3% were zoonotic, with 71.8% of those originating in wildlife. Sources: WHO · Jones KE et al., “Global trends in emerging infectious diseases,” Nature 451:990–993 (2008), DOI 10.1038/nature06536.

One Health is therefore not simply a fashionable slogan. It is an attempt to organise surveillance and prevention around biological reality: human, animal, plant and ecosystem health are interdependent. Sources: WHO.

Six lessons we keep relearning

Disease X — preparing for what we cannot name

WHO uses “Disease X” to represent the knowledge that a serious international epidemic could be caused by a pathogen currently unknown to cause human disease. It is not a prediction of a particular mystery virus; it is a planning concept designed to force preparedness beyond a short list of familiar organisms. Sources: WHO R&D Blueprint.

That is perhaps the right way to think about the next pandemic. The organism may be an influenza virus, a coronavirus, a henipavirus, a resistant bacterium, a vector-borne pathogen or something we have not yet identified. The pathogen changes. Much of the preparedness architecture does not. Sources: WHO R&D Blueprint · WHO.

Surveillance. Laboratory capacity. Sequencing. Epidemiology. Infection control. Healthcare capacity. Rapid research. Clear communication. International cooperation. Public trust.

So, what’s next?

In 1999, after enterovirus, haze and the encephalitis outbreak that became Nipah, I asked: “What’s next?” We eventually found out. West Nile appeared in New York. SARS followed. Then H1N1. Then COVID-19. Meanwhile H5N1 never really went away, Nipah continued to spill over, and antimicrobial resistance became a global threat of a very different kind. Sources: Cybermed-Enews Archive 1997–2003 · West Nile Fever · WHO · FAO/WHO/WOAH · WHO.

Twenty-seven years later, I am less interested in predicting which organism comes next. Prediction is seductive because it gives us the illusion that preparedness means correctly identifying the enemy. It does not.

H5N1 may never cause the next pandemic. Nipah may remain devastating but geographically contained. Disease X may be something we have never encountered. And antimicrobial resistance may continue its quieter erosion of one of medicine’s greatest achievements.

What matters is not whether we guess correctly. It is whether surveillance detects the signal, laboratories recognise it, health systems respond, scientists are heard, governments act and the public still trusts what it is being told.

In 1999 I asked, “What’s next?”

Twenty-seven years later, perhaps that is no longer the most important question.

We cannot know what comes next. But after nearly thirty years of warnings, we should know what to do when it comes.

The next pandemic may already be here — not yet as a pandemic, perhaps, but as a virus circulating in animals, an unusual cluster of human infections, a resistant organism spreading quietly through hospitals, or a pathogen nobody has named. Sources: WHO R&D Blueprint · WHO · WHO.

The question is whether we will recognise the warning in time.