UKHSA report ranks flu and new coronavirus as top pandemic threats

Respiratory viruses top UKHSA's pandemic list

The UK Health Security Agency has published a five-year risk assessment that ranks 21 health threats that could spark a pandemic in the UK, with influenza and a new coronavirus placed at the top of the list.

Coverage of the report published on June 12 says the agency sees respiratory infections as the biggest pandemic risk overall. The assessment is designed as a preparedness tool for government and public-health planners, not as a prediction of what will happen.

The timing matters because the report lands as governments continue to reassess how to prepare for large outbreaks after Covid-19, while also managing routine pressure from seasonal flu and other infectious diseases.

What the assessment says

The report groups threats by transmission route and looks at how each could affect health systems and society. It covers respiratory threats, contact-transmitted infections, vector-borne diseases, foodborne illnesses, sexually transmitted and blood-borne infections, and environmental hazards.

The two highest-ranked scenarios in the respiratory category are flu and a novel coronavirus. According to the coverage, one worst-case flu scenario suggests a new strain could infect more than half of the UK population across multiple waves over two years.

A separate worst-case scenario for a Covid-like virus says a novel coronavirus could infect 10 million people in the UK and cause 100,000 deaths in the first year. The report presents these as plausible high-end outcomes, not forecasts.

The wider threat list

Beyond respiratory disease, the report flags measles, tuberculosis, mpox, Ebola, invasive candidiasis, lassa fever, Nipah virus, dengue, Zika, STEC, typhoid, salmonella, drug-resistant gonorrhoea and hepatitis B among the assessed threats.

That broad spread is one reason UKHSA says the challenge is complex. The agency is not only weighing the possibility of a single major respiratory outbreak, but also a range of other infections that could disrupt services in different ways.

Why UKHSA says the risk is hard to predict

UKHSA chief data officer Steven Riley is quoted as saying the UK still faces diverse and complex health security threats and that their timing and size are difficult to predict.

That framing is important. The report is aimed at preparedness, surveillance and planning, rather than trying to put a date on the next crisis. It reflects the reality that outbreaks can emerge from different routes, with different speeds and different health-system impacts.

Preparedness implications

The assessment also points to broader drivers that can change risk over time, including vaccination levels, global travel and environmental conditions that may help vector-borne diseases spread.

For health planners, the value of the report is in identifying where the biggest vulnerabilities may lie before a crisis arrives. Respiratory viruses remain the clearest priority, but the list also suggests that foodborne, blood-borne, vector-borne and drug-resistant infections still matter to pandemic preparedness.

The immediate question is whether UKHSA publishes a standalone news release or fuller methodology to explain the ranking in more detail, and whether other official or independent summaries add further context around the top scenarios.

For now, the report is a reminder that pandemic planning is not limited to one disease family. UKHSA's assessment treats a range of outbreaks as plausible, while making clear that the timing, scale and consequences of any future event remain uncertain.