‘Unprecedented’ flu season forces Welsh school closure

In response to a “significant outbreak of flu-like illness”, a school in Caerphilly, Wales has closed. The head teacher described the closure as a “firebreak” to allow for deep cleaning and for the illness to pass.

The school is not the only one experiencing significant absence.

Flu season

As reported by the BBC, 242 pupils are absent from St. Martin’s in addition to 12 members of staff. The listed symptoms include:

vomiting, diarrhoea, high temperatures, cough, headaches, fatigue and “general flu-like effects”

It’s reported that the average recovery time is roughly a week.

While the government doesn’t list how many pupils St. Martin’s has, it was 979 in 2019. This means there could have been as much as 25% of the school off at once. This percentage may have risen even further if the school hadn’t closed.

Notably, St. Martin’s isn’t the only school facing mass illness. Brian Guthrie of Ebrington Primary School reported that 170 children were off sick on a single day. Primary schools have fewer children than secondary schools, so this could represent more than 25%.

This is how the tern social media account reacted to the illnesses in Londonderry:

People still don't understand that they have been made more vulnerable by repeat covid infections. https://t.co/0Q1QjDuNZl

— tern (@1goodtern) December 6, 2025

In a recent article on Covid and immunity for the bmj, Nick Tsergas wrote that:

Over the past three years… reports have circulated of rising bacterial infections, flare-ups of old viruses becoming more common, and children landing in hospital with diseases not usually seen in young, healthy people. One explanation offered by public health leaders has been “immunity debt”—the idea that precautions taken in the covid pandemic suppressed routine exposures to circulating pathogens, leaving people more vulnerable to them when restrictions were lifted.

The theory landed in the public consciousness at the right moment. A simple idea that sounded like science, it soothed a public seeking answers just as the world was returning to a semblance of normality. And it served a policy function, allowing governments to focus on economic recovery.

But its explanatory power has faded as the number of non-covid infections has kept rising each year. A 2024 analysis by the US Centers for Disease Control and Prevention found that invasive group A strep infections saw their most dramatic year-on-year increase from 2021 to 2022, well after most precautions had been lifted in the US. Rates have been abnormally high since then, raising questions about what might be behind the trend.

A growing number of scientists believe that the SARS-CoV-2 virus may instead be subtly altering our immune systems. If correct, their hypothesis will change how we understand everything from respiratory syncytial virus (RSV) to shingles to sepsis.

2025

It was predicted in October that the 2025 flu season would be the worst in several years due to how early cases began to rise:

The following is the most recent version of the above chart:

The overall number of cases may not give the perfect picture of what’s happening, as the NHS reported 1,700 flu patients last week. While the above graph shows cases have moved closer to the 22-23 and 24-25 seasons, 1,700 patients is actually 50% higher than the same period last year.

Reportedly, the current flu virus seems to be more severe than other strains, and NHS leaders are warning the coming flu season will likely be ‘unprecedented’.

Featured image via St. Martins