Flu and COVID-19 remain low as RSV activity rises in October surveillance

Flu and COVID-19 remained at low levels in the week of 19–25 October 2026, while respiratory syncytial virus (RSV) activity increased but remained at baseline levels, according to the UK Health Security Agency’s winter surveillance bulletin.

The figures show little change in most flu indicators and a decline in overall COVID-19 activity. UKHSA urged those eligible for winter vaccinations to book before viruses circulate more widely, while warning that the course of the season remains difficult to predict.

The bulletin also records norovirus activity within expected levels, but there is no update on hospital outbreaks because the reporting system has gone offline.

Respiratory viruses: 19–25 October

In week 43, influenza positivity in laboratory surveillance was 6.6%, compared with 6.4% the previous week. The overall flu hospitalisation rate was described as stable at 2.47 admissions per 100,000 people, against 2.38 previously.

COVID-19 positivity fell slightly to 8.3%, from 8.8%. Hospitalisations remained stable at 2.76 per 100,000, compared with 2.65, while admissions to intensive care or high-dependency units remained low at 0.07 per 100,000, against 0.06.

RSV indicators rose. Laboratory positivity increased to 1.5%, from 0.9%, and the overall weekly hospital admission rate reached 0.52 per 100,000, compared with 0.31. Despite those increases, UKHSA classified activity as remaining at baseline levels.

Dr Alex Allen, a consultant epidemiologist at UKHSA, said flu remained at low levels after some activity earlier in the autumn. Although flu was unpredictable, cases usually rose during November, he said, urging eligible people to book their vaccination now. He described vaccination as the best defence and stressed the importance of receiving a flu vaccine every year.

Allen said RSV was beginning to increase but remained very low, while COVID-19 was also at low levels. Rhinovirus, which causes the common cold, remained the most widely circulating respiratory virus, making a cold the most likely explanation for respiratory symptoms, he said.

UKHSA will continue monitoring respiratory viruses throughout winter. Allen urged eligible people to book their NHS winter vaccines and parents to ensure their children received the nasal spray flu vaccine as soon as possible.

Norovirus and rotavirus

Norovirus activity had stabilised in recent weeks and remained within expected levels. Laboratory reports for weeks 42 and 43, covering 12–25 October 2026, were 39.0% below the five-season average for the equivalent fortnight.

Rotavirus activity had decreased in recent weeks and was also within expected levels, although activity over the same two weeks was 5.2% above the five-season average.

The Hospital Norovirus Outbreak Reporting System (HNORS) was offline, leaving no updated count of hospital norovirus outbreaks for the latest bulletin.

The bulletin labels its latest norovirus typing figures as covering the 2025/2026 season to date, although the surveillance reports are presented for the 2026/2027 season. Of the samples characterised in those figures, 88.6% were norovirus genogroup 2 (GII). The most frequently identified genotypes were GII.4[P16], at 24.1%, and GII.9[P7], at 20.5%.

UKHSA said it had strengthened surveillance ahead of winter by introducing a dual-typing method. This identifies both the capsid and polymerase types in a single test, producing a combined genotype and improving its ability to track circulating strains and detect emerging recombinant noroviruses. The agency identified GII.4[P16] as the most commonly detected genotype so far this season.

The agency has also retrospectively linked genomic surveillance records with health data to investigate whether illness severity differed between GII.4 and GII.17, the two most common genotypes circulating in recent seasons. The bulletin describes the analytical work but does not give a finding on differences in severity.

Amy Douglas, UKHSA’s lead epidemiologist, said the more advanced testing provided a clearer picture of circulating genotypes, allowing emerging variants to be identified more quickly and changes in norovirus epidemiology to be understood more fully. Linking laboratory and health data would also help assess differences in illness severity, monitor trends and provide stronger evidence for public health action, she said.

Advice on preventing norovirus

Norovirus can cause nausea, vomiting and diarrhoea, as well as a high temperature, abdominal pain and aching limbs. Dehydration is a particular concern for young children, older people and those with weakened immune systems. People who become ill should drink plenty of fluids.

UKHSA advises washing hands with soap and warm water and using bleach-based products on clean surfaces to help prevent infection spreading. Alcohol gels do not kill norovirus and should not be relied upon alone.

Anyone with diarrhoea and vomiting should stay away from work, school or nursery until 48 hours after symptoms have stopped, and should not prepare food for others during that period. People who are unwell should also avoid visiting hospitals and care homes to protect those most vulnerable to infection.

Earlier update: 22 October

The preceding bulletin, covering respiratory surveillance for week 42, from 12–18 October 2026, described flu activity as stable at baseline levels. COVID-19 showed mixed trends at low levels, while RSV showed mixed trends at baseline levels.

That edition recorded flu laboratory positivity of 6.3%, compared with 6.2% the previous week. Flu hospitalisations rose slightly to 1.94 per 100,000, from 1.81.

COVID-19 positivity was described as stable at 8.9%, against 8.8%. Hospitalisations increased slightly to 2.64 per 100,000, from 2.48, while intensive care and high-dependency admissions remained low at 0.05 per 100,000, compared with 0.06.

RSV positivity remained stable at 0.9%, against 0.8%, while the overall weekly hospital admission rate rose to 0.33 per 100,000, from 0.23.

Dr Jamie LopezBernal, a consultant epidemiologist at UKHSA, said the early rise in flu seen in previous weeks had slowed and COVID-19 remained at low levels. He said the agency would track the major respiratory viruses throughout winter to identify trends early and keep the public informed.

LopezBernal cautioned that low activity did not make the coming weeks easy to predict. He urged eligible people to book their free NHS flu, COVID-19 or RSV vaccination, and parents to ensure children received their nasal spray flu vaccine before wider winter circulation.

For weeks 41 and 42, covering 5–18 October 2026, the earlier bulletin recorded a slight recent decline in norovirus activity, which remained within expected levels. Laboratory reports were 32.6% below the five-season average for the equivalent fortnight.

Rotavirus activity had also decreased in recent weeks and remained within expected levels, although it was 9.8% above the five-season average for that two-week period.

At that point, the number of norovirus outbreaks reported to HNORS since the start of the 2025/2026 season was 42.0% below the five-season average. The edition reported that 87.8% of characterised samples were genogroup 2, with GII.4[P16] accounting for 25.0% and GII.9[P7] for 22.3%.

Earlier update: 15 October

The 15 October bulletin described influenza activity as stable at baseline levels, with some indicators showing a decrease among young adults. COVID-19 activity showed mixed trends and remained low, while RSV activity increased but remained at baseline levels.

For week 41, covering 5–11 October 2026, flu laboratory positivity was described as stable at 6.0%, compared with 6.2% the previous week. Overall flu hospitalisations were unchanged at 1.88 per 100,000.

Some previous-week comparators in the latest bulletin differ from the figures published in earlier editions; the supplied bulletin does not explain those differences. The flu, COVID-19 and RSV surveillance report, and the national norovirus and rotavirus surveillance reports for the 2026/2027 season, are published weekly.