National health officials have released new data showing a seasonal rise in respiratory illnesses across England, as laboratory reports highlight the current spread of infectious diseases heading into autumn.
The UK Health Security Agency (UKHSA) published its latest “causative agents” report on 20 September 2026, covering laboratory notifications for the week ending the same day. These reports are a vital part of the UK’s disease surveillance system, tracking pathogens that laboratories are legally required to report under the Health Protection (Notification) Regulations 2010.
Data from the preceding week, ending 13 September, already indicated a seasonal shift. Emergency department attendances for acute respiratory infections and asthma saw a notable increase, particularly among children under the age of 14. Public health officials noted that this trend often coincides with the return to school and the start of cooler weather, leading to higher rates of “influenza-like” and COVID-19-like illnesses.
West Sussex monitoring and screening alerts
The national report comes as local health officials in West Sussex monitor specific trends within the county. On 14 September 2026, West Sussex County Council issued a public health alert regarding a decline in chlamydia screening rates among young people aged 15 to 24. Local data shows that screening participation in the county fell from 15.3% to 14.4% between 2024 and 2025.
To address this, the council is encouraging residents to make use of free, discreet home testing kits, which can be ordered online. The county also maintains a dedicated Health Protection Dashboard to track the prevalence of various infectious diseases mentioned in the national surveillance reports.
Health officials have clarified that laboratory notifications are preliminary and serve as an early warning system. They do not always equate to a confirmed clinical diagnosis, as laboratory processes and reporting speeds can vary.
Expanded reporting and measles concerns
The scope of national disease monitoring was significantly expanded on 6 April 2025. Following regulatory changes, laboratories must now report a wider range of pathogens, including Norovirus, Respiratory Syncytial Virus (RSV), and MERS-CoV. This expansion was designed to provide a more comprehensive picture of circulating viruses and bacteria that impact public health.
The 2026 data also continues to track the impact of measles, which remains a significant concern for health authorities. Between 1 January and 8 June 2026, England recorded 736 confirmed cases of measles and two deaths. Officials continue to urge parents to ensure children are up to date with the MMR (measles, mumps, and rubella) vaccination programme.
As the UK enters the autumn period, UKHSA and local authorities advise residents to follow standard hygiene practices, such as regular handwashing, to mitigate the spread of seasonal respiratory infections and norovirus.
