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Saturday, January 28, 2012

Post #28 Respiratory Syncytial Virus (RSV) - Dispelling Some Myths

One of the common fear-inducing germs that moms ask me about during the wintertime is the Respiratory Syncytial Virus more simply known as RSV. Most moms correctly recognize the germ as a potentially devastating illness, however there are some common misconceptions about the germ that I would like to clarify.

Probably the most common misconception is that RSV is always dangerous; while RSV can be dangerous it typically is not.
RSV is one of many known viruses which causes the common cold (there are over 200). The majority of people who acquire RSV will go on to have typical cold symptoms including cough, runny nose, and possibly fever. Most people will recover within a few weeks without any long term complications.

However, the very first time a human being catches RSV, there is a higher probability of lung involvement leading to either bronchiolitis (inflammation of the small airways) or pneumonia (inflammation of the lungs involving the air sacs); as such the younger you are the more likely you will have lung involvement with an RSV infection. Additionally, there is greater risk of severe disease in children who were born premature (especially less than 35 weeks gestation).

So if your child is younger than 6 months of age and in particular if they were under 35 weeks gestational age when born, there is greater risk of serious illness from an RSV infection.

The older your child becomes three things will favor them against serious complications:

1. There immune systems will mature.
2. They will become physically larger (as will their airways).
3. They will encounter the RSV germ repeatedly giving them greater antibody protection with each subsequent illness.

It should be noted that the elderly are also affected more significantly by RSV than a healthy young adult, however as a pediatrician I do not have any expertise in this population.

The second common misconception is that RSV can be avoided - it cannot. Almost every child will become infected with RSV at least once by their second birthday and reinfection is common.

RSV, like other cold viruses, is spread through respiratory droplets (i.e. sneezes and coughs) but more commonly it is spread via direct contact with other infected children and the surfaces they touch. It really is a matter of WHEN and not IF your child will catch RSV. As stated above, children's bodies handle RSV better as they get older.

Thus if your child is a preemie and/or they are under 6 months of age, it makes sense to take some precautions to delay the initial onset of the inevitable first acquisition of RSV. Typical hygienic habits are what serve you best: washing hands, portable hand cleanser, and covering sneezes appropriately (elbow method is best).

The last misconception is not as common and is not really a true misconception. As a pediatrician, I am often asked whether RSV lung infection will increase the risk of asthma in the future. The short answer is - it's complicated.

A good way to think about this is the chicken or egg analogy.

Do kids that are more prone to asthma genetically have a greater propensity of having lung involvement with their very first RSV infection?


Or does an early infection with RSV increase the chances of having asthma later in life?


One of those statements is likely true and possibly both. The research has not definitively answered either question adequately and we will likely never know for sure. What we do know is that RSV infection in the lungs (everyone eventually gets it but not everyone gets involvement of the lungs) has some correlation with recurrent wheezing. But we also know that long-term there are no permanent changes found in the lungs of these same children - at least not as a result of RSV.

The bottom line is that your child will catch RSV at some point in their life and it will likely manifest itself as nothing worse than the common cold. However if your child is under 6 months of age and particularly if they were born premature, healthy hygiene may prevent lung involvement and thus reduce the risk of serious illness. Finally, should your child have lung involvement with their RSV illness, they have a greater risk for recurrent wheezing, however the RSV germ should not cause long-term changes in their lungs.

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