What is RSV? Symptoms of respiratory syncytial virus explained, and why NHS expects an outbreak this winter

Outbreaks of influenza and respiratory syncytial virus (RSV) could lead to double the amount of related hospital admissions this winter, a major new report has warned.

According to the review by the Academy of Medical Sciences - which was requested by the Government’s chief scientific advisor Patrick Vallance to review the biggest health risks this winter - primary care would experience particular pressure from an RSV outbreak, due to GPs seeing the majority of these patients.

Alongside this, Public Health England (PHE) surveillance shows RSV samples have increased over the last five consecutive weeks from 1.2 per cent to 8.9 per cent.

But what is RSV and why are doctors expecting an outbreak?

Here’s what you need to know.

What is RSV?

Respiratory syncytial virus - also known as RSV - is a common respiratory virus that usually causes mild, cold-like symptoms.

Although most people recover in a week or two, RSV can be serious at times, especially for infants and older adults.

What are the symptoms?

People infected with RSV usually show symptoms within 4 to 6 days after getting infected.

Symptoms of RSV infection usually include:

- Runny nose

- Decrease in appetite

- Coughing

- Sneezing

- Fever

- Wheezing

These symptoms usually appear in stages and not all at once, according to the Centres for Disease Control and Prevention (CDC).

In very young infants with RSV, the only symptoms may be irritability, decreased activity, and breathing difficulties.

According to the NHS, bronchiolitis - which is a common lower respiratory tract infection that affects babies and young children under two years old - is almost always caused by a viral infection. In most cases, the respiratory syncytial virus (RSV) is responsible.

RSV is a very common virus and almost all children are infected with it by the time they're 2 years old.

In older children and adults, RSV may cause a cough or cold, but in young children it can cause bronchiolitis.

Why are doctors expecting an outbreak of RSV this winter?

The Academy of Medical Sciences report said that GP, hospital and NHS 111 services will need to help “prevent large numbers of children and older patients with breathing difficulties from being triaged with the outcome of an emergency ambulance” during any potential RSV outbreak.

According to new modelling for the report, between 15,000 and 60,000 people could die from influenza (flu this winter), although the planned widespread flu vaccination should help to reduce this risk.

RSV and influenza respiratory outbreaks were kept at bay last winter due to social distancing measures, but with restrictions easing they “might overlap” with a peak in Covid-19 infections, said the report.

The report also noted that face-to-face appointments in general practice will be best suited for deciding the most appropriate outcome for patients, “which would result in a large extra workload in primary care”.

Pressures on primary care are expected to “intensify” this autumn and winter due to not only respiratory outbreaks, but more Covid-19 patients being treated in the community and delayed treatment causing chronic conditions to worsen.

The report called for an expansion of Covid testing to include influenza and RSV, wider use of antivirals to treat flu, increasing the speed and uptake of Covid vaccination, and clearer Government guidance about the precautions the public can take against Covid, such as wearing face coverings in crowded indoor spaces.