On 9 June 2022, the House of Lords is due to debate the following question for short debate:

Baroness Ritchie of Downpatrick (Labour) to ask Her Majesty’s Government what assessment they have made of the cost to the NHS associated with managing respiratory syncytial virus infections.

What is respiratory syncytial virus?

Respiratory syncytial virus, or RSV, is one of the common viruses that cause coughs and colds. It is in the same family as the human parainfluenza viruses and mumps and measles viruses. Government public health guidance (produced in September 2021 by Public Health England before it was replaced by two new agencies) explains that RSV is transmitted by large droplets from contact with an infected person. The virus can survive on surfaces or objects for about four to seven hours. It has a short incubation period, with a delay of about three to five days between infection and the appearance of symptoms.

RSV infection is common in children. Public Health England (PHE) estimated that over 60% of children have been infected by their first birthday, and over 80% by two years of age. However, the antibodies that develop following early childhood infection do not prevent further RSV infections throughout life.

For most people, RSV infection causes a mild respiratory illness. However, for a small number of people who are at risk of more severe respiratory disease, RSV might cause pneumonia or even death. Symptoms of an RSV infection include a runny nose, sneezing, nasal congestion, a cough and sometimes a fever. Ear infections and croup (a barking cough caused by inflammation of the upper airway) can also occur in children. RSV is the leading cause of bronchiolitis in babies and infants, an infection of the small airways in the lung which can make breathing harder and cause difficulty feeding.

PHE identified the very young (under one year of age) and the elderly as those at the greatest risk from RSV. Infants under six months frequently develop the most severe disease, such as bronchiolitis and pneumonia, which may result in hospitalisation. Children born prematurely or with underlying chronic lung disease, and elderly people with chronic disease, are also at increased risk of developing severe disease.

PHE noted that only a minority of adult infections are diagnosed, as RSV is not widely recognised as a cause of respiratory infections in adults. Elderly patients are frequently not investigated microbiologically, as there are fewer viruses present in their respiratory secretions compared to children. PHE said this resulted in the number of adult infections being underestimated.

According to the PHE guidance, there is no specific treatment suitable for general use in cases of RSV, and treatment is therefore aimed at supporting the patient and relieving symptoms. The British National Formulary treatment summary for RSV explains that ribavirin, an antiviral drug, is licensed to be administered by inhalation for the treatment of severe bronchiolitis caused by RSV in infants, especially when they have other serious diseases. However, it states there is no evidence that ribavirin produces clinically relevant benefits in RSV bronchiolitis.

Immunisation with the monoclonal antibody palivizumab (sold under the brand name Synagis) is recommended for children in high-risk groups, including pre-term infants with chronic lung disease or congenital heart disease, and children under two with severe combined immunodeficiency syndrome.

Changes in patterns of infection

Until recently, RSV infections were seen to follow a relatively predictable seasonal pattern. Guidance for healthcare workers written in 2015 describes RSV as “a clearly identified winter virus, usually occurring in the UK within the period October to March with most infections occurring in a relatively short epidemic of about six weeks”. PHE noted that “the sharp winter peak varies little in timing or magnitude, in contrast to influenza virus infection which is much less predictable in its timing”.

However, measures adopted from March 2020 onwards to prevent the spread of Covid-19 also affected transmission of RSV. The government noted in March 2021 that the rate of RSV had been much lower than expected since June 2020. It said the likely cause for this was pandemic-related measures such as social distancing, lockdowns and the wearing of masks.

Public health officials warned in summer 2021 that the lower levels of infection the previous winter meant many children would not have developed immunity to RSV. They predicted this might lead to a rise in cases in young children in the second half of 2021 compared to a typical season.

This was not unique to the UK: unseasonal ‘surges’ in RSV infection were also observed in places such as the southern United States, Switzerland and Japan in summer 2021. A report published in July 2021 by the Academy of Medical Sciences noted that:

The recent easing of social contact rules has led to a summer surge of infections that are typically seen in the winter, including RSV, bronchiolitis, parainfluenza and rhinovirus. RSV is a major cause of hospitalisation and mortality in young children, particularly those less than one year old. Evidence from Australia and South Africa suggests an increase in RSV in children in summer following an RSV-free winter in lockdown. Modelling data from the United States suggests that the loss of population immunity to RSV amongst young children may create a larger susceptible population that is potentially likely to have a larger outbreak this winter.

The report called for increased paediatric intensive care capacity, increased access to palivizumab, and the introduction of multiplex testing for SARS-CoV-2 (the virus that causes Covid-19), RSV and influenza to help manage infections among children and vulnerable adults over the winter.

The UK government’s scientific advisors also drew attention to the possible implications of changing patterns of RSV infection for managing public health in the future. SPI-M-O, the pandemic modelling sub-group of the Scientific Advisory Group for Emergencies (SAGE), warned in July 2021 that the change in the transmission dynamics of RSV and influenza as a result of Covid control measures could lead to “a period of unpredictable epidemics of these diseases before their normal seasonal pattern returns”. The New and Emerging Respiratory Threats Advisory Group (NERVTAG) concluded in September 2021 that a “larger than normal” RSV season was possible over winter 2021–22 because “RSV epidemiology is governed by naturally acquired immunity (not vaccination) and contact patterns in children (which are now back to normal levels)”. In October 2021, SAGE identified the co-circulation and co-infection of SARS-CoV-2, RSV and influenza as “a significant challenge” for the coming winter.

However, by January 2022, RSV infections were reported to be lower than usual for the time of year. Lord Kamall, parliamentary under-secretary of state at the Department for Health and Social Care, said the unseasonal surge in RSV activity the previous summer had peaked in late July 2021 at about 15.7% swab positivity and a hospital admission rate of 2.5%. He said the summer surge had been centred on child cases, with few cases among elderly adults. Lord Kamall said RSV activity had subsequently declined and by January 2022, positivity was below seasonally expected levels, with a corresponding decrease in the hospitalisation rate since the summer surge.

Impact on the NHS

Academic studies have attempted to measure the ‘burden’ of disease attributable to RSV. A 2016 study looking at RSV in 0–17 year-olds between 1995 and 2009 found that in the UK, RSV accounted for approximately 450,000 GP appointments, 29,000 hospitalisations and 83 deaths per year in children and adolescents, the majority in infants. The study concluded that:

The burden of RSV in children in the UK exceeds that of influenza. RSV in children and adolescents contributes substantially to GP office visits for a diverse range of illnesses, and was associated with an average 416,133 prescribed antibiotic courses per season. Effective antiviral treatments and preventive vaccines are urgently needed for the management of RSV infection in children.

A similar study published in 2015 looked at the burden of RSV in adults over the same period (1995–2009). It estimated that among adults, approximately 487,000 GP episodes, 18,000 hospitalisations and nearly 8,500 deaths were attributable to RSV per average season. Of these, around 175,000 GP episodes (36%), around 14,000 hospitalisations (79%) and just under 8,000 deaths (93%) were in people aged 65 or older. The study found that high-risk elderly people were twice as likely to have an RSV-related GP episode or to die from RSV-related causes than low-risk elderly people. High-risk elderly people were four times more likely to be hospitalised for RSV than low-risk elderly people. The study found that in most seasons between 2001 and 2009, more GP episodes, hospitalisations and deaths were attributable to RSV in adults than to influenza.

The government set out in January 2022 what it was doing to monitor the impact of RSV on the NHS:

There is a national response and governance in place to manage surges in paediatric respiratory infections, including respiratory syncytial virus (RSV). This includes monitoring of relevant data on RSV prevalence and hospital activity and a coordinated approach with the devolved administrations.

Sentinel surveillance of RSV cases was established in May 2021 to expand sample testing and provide an early warning system. The surveillance data is being reviewed on a weekly basis by the UK Health Security Agency (UKHSA) and NHS England and NHS Improvement. Through the Severe Acute Respiratory Infection Watch programme, the UKHSA undertakes surveillance of hospitalisations with confirmed RSV infection to sentinel National Health Service hospital trusts in England, including intensive care admissions.

A Paediatric Incident Cell has been established within NHS England and NHS Improvement to manage the RSV response and monitor pressures on local services with a national Critical Care Capacity Panel (CCCP). Weekly surveillance data, daily data on hospital activity, general and acute as well as paediatric intensive care bed occupancy, is being monitored as part of the CCCP and the Paediatric Incident Cell.

NHS England introduced additional measures to tackle RSV from April 2021 as concerns emerged about a possible summer surge. Paediatric units brought their usual winter planning forward to provide additional bed and workforce capacity. The NHS offered palivizumab immunisations for at-risk children earlier in the year than usual, and with an increased number of doses, following advice from the Joint Committee on Vaccines and Immunisation. PHE extended its respiratory illness surveillance system, ensuring that it ran over the summer months rather than stopping between May and October as usual.

The UK Health Security Agency, one of the successor organisations to PHE, publishes weekly surveillance reports that monitor RSV activity as well as Covid-19, seasonal flu and other respiratory illnesses. The most recent report (data for the week between 16 and 22 May 2022) states that RSV positivity remains low, with the highest positivity in under-five year-olds.

Cover image by Mojpe from Pixabay.