Menaces of winter: Respiratory infections in young infants

Menaces of winter: Respiratory infections in young infants

By Andrew James, MBChB, FRACP, FRCPC

The Toronto RSV Prophylaxis Collaborative Group hosted the fifth annual fall RSV Symposium in Toronto on October 6, 2004. The theme of the symposium was respiratory syncytial virus (RSV), influenza, and related infections in young infants with a particular emphasis upon infants at risk for RSV infection, infection control, and RSV prophylaxis.

New developments in the prevention of pneumococcal infections were also discussed.

The 140 attendees included paediatricians, family physicians, nurses, respiratory therapists, pharmacists, and public health nurses from within the greater Toronto area and beyond.

RSV is the most common cause of respiratory infection in young infants. Nearly 60% of infants are infected in the first year of life. Almost all children have been infected by RSV by two years of age. The signs of an RSV infection are usually a runny nose and wheezing. The chest X-ray may show the presence of pneumonia.

Infants considered at high risk for RSV infection include preterm infants born before 35 weeks of pregnancy, and infants with a major congenital heart condition.

Infection control measures, especially hand and respiratory hygiene, play a critical role in reducing the frequency of RSV infections by limiting the spread of the virus. At present there is no active immunization against RSV because we lack a safe and effective vaccine.

Passive immunization with an antibody against RSV called palivizumab (Synagis) is recommended as a strategy to prevent RSV infection. Prophylaxis is recommended for all high-risk infants during the winter months. Palivizumab is given by intramuscular injection. Injections are given at monthly intervals starting in October or November, and continuing until March or April. In Ontario, palivizumab is provided by Canadian Blood Services for all high-risk infants eligible for RSV protection as defined in recommendations published by the Canadian Paediatric Society.

Other viruses causing respiratory infections in young infants include the influenza and parainfluenza viruses and the adenovirus. All of these viruses can cause serious illness in some young infants.

In Canada, the National Advisory Committee on Infection recommends annual immunization against the flu for those over six months of age. In children, the vaccine is about 80% – 90% effective in preventing the flu and about 60% – 70% effective in preventing illness with fever. Immunized children who do get the flu have fewer middle ear infections.

The risk of the vaccine causing serious harm is extremely small. Life-threatening allergic reactions are very rare. Young infants and children cannot get the flu from the vaccine. The flu vaccine is safe for breastfeeding mothers and for pregnant women at all stages of pregnancy.

Bacterial infections also cause illness in young infants and children. The bacterium Streptococcus pneumoniae, more commonly known as pneumococcus, is an important cause of illness in young infants and children under the age of five. Pneumococcus most commonly causes an illness with fever without a known focus of infection. It is a common cause of middle ear infection, and the leading cause of bacterial meningitis among children under the age of five years.

A new pneumococcus vaccine (PCV), sold under the brand name Prevnar, was licensed in 2000. Prevnar protects against the seven types of pneumococcal bacteria that cause most of these infections. The vaccine serotypes account for 86% of pneumococcal bloodstream infections, and 83% of pneumococcal meningitis among infants less than six years of age. Prevnar is 90% effective against invasive pneumococcal disease if four doses are given to children less than two years of age. It is 20% effective against pneumonia, and 6% effective against acute middle ear infection. The vaccine is safe. Local reactions occur in 10% – 20% of children. Fever and muscle aches occur in 15% – 24% of children. Severe adverse reactions are rare.

In Ontario, PCV vaccination is publicly funded for high-risk infants and young children less than six years of age. On January 1, 2005, the PCV vaccine will be available to all children born on or after January 1, 2004. The recommended number of doses depends upon the infant’s age when starting the vaccination program.

Check with your child’s physician, or a public health nurse, for further information about your child’s immunization schedule.

Andrew James, MBChB, FRACP, FRCPC
Chief Medical Editor, AboutKidsHealth
http://www.aboutkidshealth.ca/News/Menaces-of-winter-I-Respiratory-infections-in-young-infants.aspx?articleID=7959&categoryID=news-type

Menaces of winter: RSV infection and bronchiolitis

December 2004 – In October, The Toronto RSV Prophylaxis Collaborative Group hosted its fifth annual fall RSV Symposium. This year’s theme was respiratory syncytial virus (RSV), influenza, and related infections in young infants with a particular emphasis upon infants at risk for RSV infection, infection control, and RSV prophylaxis.

The 140 attendees included paediatricians, family physicians, nurses, respiratory therapists, pharmacists, and public health nurses from within the greater Toronto area and beyond.

Bronchiolitis, a common disease of the lungs that occurs most often in winter, is caused by the respiratory syncytial virus (RSV). The disease almost always starts as a cold or upper respiratory tract infection. The typical features of bronchiolitis include fever, a runny nose, rapid breathing, cough, and wheezing. Infants less than six months of age, especially those who were born prematurely, may stop breathing. The chest X-ray may show the presence of pneumonia.

The severity of the infant’s symptoms influences the treatment of bronchiolitis. Drinking small quantities of fluids often, together with regular administration of acetaminophen to keep the infant’s temperature below 38.5ºC, may be all that is needed for mild infections. Some children are admitted to hospital because they need oxygen, intravenous fluids, and close observation. A very small number of children need help with their breathing.

RSV causes respiratory tract infections amongst all age groups. The infection occurs most often and is most severe in young infants aged 3-6 months. Nearly 60% of infants are infected in the first year of life. Almost all children have been infected with RSV by 2 years of age. Re-infection is common throughout life.

The incubation period for RSV is 2-8 days but is most commonly 4-6 days. Infected children shed the virus as droplets in their respiratory secretions for 3-8 days. Shedding of RSV may occur for as long as 3-4 weeks in infants. RSV may survive on the skin for 30 minutes, on a cloth for 1-2 hours, and on hard surfaces for up to 8 hours.

Young infants and toddlers usually catch the infection from older brothers and sisters, or from playing with other children in the home or at day care. Infection with RSV occurs through contact with the contaminated droplets that are produced by sneezing and coughing. RSV enters the body through the nose, mouth or eye. Infants and young toddlers may also catch the virus by touching their nose, mouth, or eye after touching a contaminated cloth or hard surface.

Infection control measures, especially hand and respiratory hygiene, play a critical role in reducing the frequency of RSV infections by limiting the spread of the virus. Frequent and proper washing of the hands is a very important method to prevent infection.

RSV protection is recommended for all high-risk infants during the winter months. Infants considered at high risk for RSV infection include preterm infants born before 35 weeks of pregnancy and infants with a major congenital heart condition. Other groups at risk include anyone with an abnormal immune system, adults with diseases of the heart and lungs, and the elderly.

Passive immunization with an antibody against RSV called palivizumab is our current approach to prevent RSV infection. Palivizumab is given by injection at monthly intervals starting in October or November, and continuing until March or April. The time in between these months is known as the RSV season. It can change slightly from year to year. This year’s season began on October 31.

In Ontario, palivizumab is provided by Canadian Blood Services for all high-risk infants eligible for RSV protection as defined in recommendations published by the Canadian Paediatric Society.

The goal of the Toronto RSV Prophylaxis Group is to identify all high risk newborn infants and offer the first injection of palivizumab before they leave the hospital where they were born. Monthly injections would be administered until the end of the RSV season.

If this approach to RSV prevention is effective, we expect to observe a reduction in the frequency and severity of RSV infections in high risk infants.

Andrew James, MBChB, FRACP, FRCPC
Chief Medical Editor, AboutKidsHealth
http://www.aboutkidshealth.ca

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