RSV is a virus that can cause serious respiratory infections (infections of the lungs and airways), such as pneumonia and bronchiolitis (inflammation of the airways). RSV infection occurs throughout life. In temperate countries like the UK, RSV occurs in epidemics each winter.
In infants, RSV is the main cause of bronchiolitis. Most cases of bronchiolitis are mild and can be managed at home, but about 3% of cases will need hospital care. Worldwide, RSV is the second largest cause of death in children under one year of age (second only to malaria). In 2017 the World Health Organization (WHO) estimated that RSV causes around 33 million serious respiratory infections a year. This results in more than 3 million hospitalisations and nearly 60,000 deaths in children under 5 years of age every year. Nearly half of these hospitalisations and deaths are in children under 6 months of age.
In the winter months, bronchiolitis is responsible for around 1 in 6 of all UK paediatric admissions (hospital admissions of babies and children). It is estimated that over 30,000 babies and children under 5 are hospitalised every year in the UK because of RSV (see this research from Public Health England ). 6% of these will need admission to intensive care. Most of these hospital admissions occur in babies who are otherwise healthy. However, babies with certain conditions are more at risk of developing more severe disease after infection (for example, babies born with heart and lung disorders and premature babies). Infants who are hospitalised with severe RSV infection are at an increased risk of developing wheeze later in life. Numbers of hospital admissions due to RSV have increased in the last 20 years. RSV causes the deaths of around 30 babies a year in the UK.
In healthy adults RSV causes symptoms similar to those of a common cold. However, it can develop into severe disease in adults with a weakened immune system (such as bone marrow transplants) and in elderly people.
This report by BBC South today from August 2017 looks at the impact that an RSV infection can have on an otherwise healthy infant. It also looks at a study being conducted by Oxford Vaccine Group and OSPREA that looks to reduce infant RSV infections by vaccinating pregnant women.
RSV is passed from person to person by close contact. The virus can survive for several hours on surfaces such as door handles and toys. RSV can also occur in hospital outbreaks, especially on paediatric wards.
The main care is supportive care (such as fluids and oxygen if needed). There is one licensed anti-viral drug to treat RSV infection, but is not commonly used because of drug toxicity and limited effectiveness. Several new treatments are being tested in clinical trials in babies at the moment. The most severe cases may need artificial ventilation (mechanical breathing support) in intensive care. Almost all infant deaths from RSV are in the developing world where such expensive care is not available.
There are synthetic (artificial) antibodies, which can be given to certain ‘at-risk’ infants. It is given by injection on a monthly basis during winter to provide short-term protection against infection. However, this treatment is not always effective and it is also expensive, putting it beyond the reach of countries in the developing world.
A vaccine to prevent RSV infection might be a cost-effective way of reducing the burden of severe RSV disease. Hospital treatment for babies with RSV costs the NHS millions of pounds every year. There is currently no licensed RSV vaccine, but a number of vaccines are now in the later stages of development and are expected to be licensed. The Oxford Vaccine Group is currently undertaking a number of projects that try to better understand the burden of RSV disease, and looking at several approaches to vaccine prevention. Studies are designed to assess the safety and tolerability of each vaccine, and how well each one stimulates the immune system. This might protect people from developing severe disease in the future.