How Contagious Is RSV?

“Only children get RSV.”

It’s a statement you’ve probably heard more than once in the past few years. Respiratory syncytial virus (or RSV, for short) has been around for a long time, but it’s been in the spotlight since the early days of the COVID-19 pandemic, when school closures, masking and other public health measures interrupted its usual seasonal pattern. Now that it’s a hot topic, misinformation about RSV’s spreading almost as fast as the virus itself.

RSV is not “just for kids.” It’s a highly contagious respiratory virus that anybody can catch and — perhaps more importantly — spread. For most people, the symptoms are mild, indistinguishable from the common cold. But in vulnerable populations, RSV can cause pneumonia or bronchiolitis, leading to hospitalization and, in some cases, death.

We talked to infectious disease specialist Ryan Miller, DO, to learn more about how contagious RSV is, how long you can expect to be contagious, and how to prevent the spread and keep people at risk of complications safe.

How does RSV spread?

RSV, like the flu, is seasonal, starting during the fall and peaking in winter. It’s usually spread by respiratory droplets. The virus has an estimated R0 of three, which means each person who contracts the virus can be expected to spread it to three other people. One of the reasons RSV is so contagious, Dr. Miller explains, is that you can spread the virus before you start experiencing any symptoms.

“RSV is mostly an issue in the daycare and school setting,” Dr. Miller notes. “It spreads among people who don’t really cover their cough, protect their sneeze and wash their hands.” Children then take the virus home with them, infecting their family members.

RSV also tends to spread quickly in congregate living environments, like skilled nursing facilities or group homes.

Hospitals are another place where the virus can spread. That’s why somebody who’s hospitalized due to RSV complications will usually be isolated from other patients — and why the team of healthcare providers working with them wear masks and plastic disposable gowns.

Can RSV transmit from adults to children/babies and vice versa?

The idea that only children can get or spread RSV is a widespread misconception.

“RSV affects almost everyone,” Dr. Miller clarifies. “You don’t really become immune to it.” In fact, you’ve probably had RSV several times throughout your life without realizing it.

“Most adults don’t get terribly sick from RSV,” he continues. “A lot of adults do get it during the fall and winter seasons, but we don’t really hear about it as much because they just get cold-like symptoms and get over it pretty easily.

“We usually start testing children with symptoms and they’re ‘the canary in the coal mine.’ When the number of kids with RSV starts going up, then we worry about it in more at-risk populations.”

The people most likely to experience severe — and potentially deadly — complications from an RSV infection are:

• Infants under 6 months old.
• Infants born pre-term.
• Children (and some adults) who have neuromuscular conditions like muscular dystrophy.
• Adults over the age of 60.
• Adults and children who have chronic heart or lung disease.
• Adults and children who are immunocompromised.

While you don’t become immune to RSV, there is an RSV vaccine currently available and approved for adults over the age of 60. Dr. Miller recommends all eligible adults get the vaccine. Additionally, an RSV vaccine for pregnant people has recently been approved, as has an immunization against RSV for babies.

How long is RSV contagious?

According to the U.S. Centers for Disease Control and Prevention (CDC), RSV is usually contagious for between three and eight days. Like COVID-19, you can spread RSV before you even know you’re sick, which is why it’s so important that you cover your cough or sneeze and wash your hands regularly throughout the day, no matter how you feel.

But if you’re feeling sick, Dr. Miller suggests you stay home and try to avoid other people. And we know masking can help prevent the spread of RSV because — like influenza — there were very few cases of RSV during the early days of COVID-19.

“If you’re not feeling well, washing your hands, covering your cough or sneeze, isolating as much as possible and masking are the biggest things that we can do to protect those that we love,” Dr. Miller reiterates. And if you’re eligible, get the RSV vaccine.