Keep Calm and CARI On

With the tail end of the year approaching, the Respiratory Team at Public Health Scotland (PHS) are gearing up to increase surveillance of respiratory infections across Scotland. In our latest blog, Helen Gadegaard, Healthcare Scientist Principal, tells us how the team gathers and shares this information.

Autumn in Scotland brings beautiful colour changes, and colder days remind us that winter won’t be far away. Excitingly, we welcome back cosy jumpers and winter-warming food. Perhaps less welcome, however, is the odd dreich day, winter fuel bills or seasonal increases in respiratory illness, including influenza and Respiratory Syncytial Virus Infection (RSV).

If we do get a bad cold, flu, COVID or any other type of infection, we’re usually able to look after ourselves and each other with sensible self-care at home, by finding advice at NHS Inform if needed, and through the protection of winter vaccinations for those who are eligible. For people who are suffering worse with more severe respiratory symptoms though, extra advice or support from a GP may be needed, or some additional care in hospital.

For PHS, autumn brings the start of the Winter Respiratory Season and a change to how we work. It’s a little strange to think that some respiratory infections have seasons, but they definitely do. We know this by keeping track year-round of who gets ill, when they get ill, and what they are ill with. This data builds a picture of seasonal respiratory infections that gets clearer even as the days become shorter.  

Collecting and analysing data is the backbone of our work. You’ll see these data collectively referred to as ‘Surveillance’ and PHS provides a weekly summary of key indicators of disease during the winter season via the ‘Viral Respiratory Diseases (including Influenza and COVID-19) in Scotland Surveillance’ report and on our digital dashboard. Our report and dashboard also include COVID-19 surveillance data, although COVID-19 is not yet classified as a seasonal respiratory illness. Other surveillance information comes to us from the Office of National Statistics COVID-19 Infection Survey, and wastewater testing which detects viral fragments of COVID-19 within the sewerage system. Reporting these together gives us a confident estimate of the COVID-19 infection rate, without needing to go back to the days when wider population testing by lateral flow devices (LFDs) was required.

But where do all these data come from?

Usually, our surveillance data comes from those who have been to see their GP or sought care in a hospital. Test results from these encounters, vaccination history, and other information – including sociodemographic data from every patient across the country – enters the NHS digital system. Data then flows anonymously from NHS Boards into PHS for analysis and reporting. From the anonymised data, we can describe near real-time trends in infections related to age, sex, and importantly, if there is a particular location affected, like a care facility.

In addition to the laboratory data coming into PHS, we also reach out to collect more information in the community among people who otherwise might not have been tested by their GP. One of the year-round ways we do this is through our Community Acute Respiratory Infection surveillance programme (CARI). CARI is a network of GP practices around Scotland which act as sentinel practices. This means they are ‘look-out’ practices.

When a CARI GP practice sees a patient with acute respiratory infection symptoms, the doctor may ask if they are willing to provide a swab sample and answer some survey questions. The swab will be tested for up to 10 different respiratory viruses and bacteria. The GP gets the results back for the patient, and PHS gets the anonymised data. This provides a robust picture of what types of respiratory infection are circulating in the community over time. This information helps to describe how well vaccines are working and whether a new infection or an as yet unknown variant is emerging.

You can find out much more detail about PHS’s work to prevent, detect and control respiratory infections in Scotland’s Infectious Respiratory Diseases Plan 2023-2024 and how samples from hospitals and CARI are used in our Plans for SARS-CoV-2 variant assessment and response. Together, these plans ensure health professionals, scientists and policy makers are best able to protect the public’s health, while letting the rest of us get on with enjoying the wintery season ahead.