Latest Covid variants and outlook for UK summer

There probably will be a Covid summer wave.

New kid on the block: NB.1.8.1

Last summer we had a large Covid wave in the UK, followed by another wave in the autumn but then things have been as quiet as they’ve been since the start of the pandemic since November 2024. Lasting six months so far, this has been a very welcome respite but it looks as if this might be coming to an end in the coming months.

A new variant called NB.1.8.1 has emerged which has quickly become dominant in China, and is taking over in Singapore, Hong Kong, Taiwan and Australia. All these countries are reporting significant increases in reported cases and hospital visits. The apparent growth advantage of NB.1.8.1 over current strains prompted the World Health Organization (WHO) to designate it a “variant under monitoring” three days ago.

It remains rare in Europe but is increasing - the WHO report that its share has grown from 1% to 6% in the most recent 4 weeks of monitoring, representing an approximate doubling of just under two weeks. Since the UK and Europe have seen low Covid activity for 6 months, and most people haven’t had a Covid booster in years, our population immunity to infection (if not necessarily severe illness) is also probably lower than it’s been for a while. This combined with the significant growth means that it’s quite possible we will see a large wave of infection here in two months or so once it becomes dominant.

That said, there is no evidence that this variant causes more severe disease and because it is an offshoot of last summer’s JN.1 strain, which is the strain used for the most recent vaccines, hopefully anyone boosted in the last 12 months will be well protected from severe illness. Thus, we might see many people getting ill, but hopefully a much lower relative increase in the number needing hospital.

Newer kid on the block: XFG

There is an even newer variant popping up which has got some Covid experts’ attention. The main worry with XFG is that it is an offshoot of a much older Coronavirus strain and has added a lot of new mutations, raising concerns that it could more easily evade our immune responses. That said, a new pre-print (research that is not yet peer-reviewed) reported that while XFG is much more immune-evasive than other current variants it is less good at attaching to and entering human cells which could limit its spread and impact. We’ve seen previous variants that have found good immune evasion nevertheless die off because they were not as good as infecting humans as other circulating variants. Ma et al, in a 2023 Nature paper, found that the ability to enter cells (via “ACE2 binding”) was if anything more important than extent of immune evasion in determining virus spread, and so I’m not too worried about this variant unless it finds a way around this problem. However, XFG shows that there are still plenty of mutational spaces for the virus to explore and a new significant variant is definitely possible.

Covid is not yet in any way seasonal

As well as the likelihood of a summer wave, I want to highlight - again - that Covid is not in any way a winter virus. It is not like RSV and Flu and its waves are not predictable. There is a desire to believe that Covid is now just another ‘winter virus’, but doing so risks leaving us unprepared when the facts are very different.