RSV in winter 2023: Everything you need to know about symptoms, treatments, shots

As the United States heads into the colder weather months, cases of respiratory syncytial virus (RSV) have been ticking up across the country.

For the week ending Nov. 25, there were 8,863 positive RSV tests recorded, according to data from the Centers for Disease Control and Prevention, which is typical for this time of year.

This is slightly down from the previous week, when 9,914 tests were recorded and compared to last year when 16,067 positive tests were recorded during the same period.

Although most cases of RSV result in mild illness, the virus can be dangerous among infants and young children as well as senior citizens.

"RSV is a very common infection," Dr. John Brownstein, an epidemiologist and chief innovation officer at Boston Children's Hospital and an ABC News contributor, said. "Of course, we want to avoid illness, but, for the vast majority of people, they will recover. These are things to take seriously and to try to protect yourself, but there's also no reason for panic."

Here's what you need to know about RSV and how to best protect yourself and others from contracting it.

How RSV spreads

RSV is a common respiratory virus. Nearly all children are infected before their second birthday, according to the CDC.

There are a few ways people can become infected, including coming into contact with the droplets of an infected person or touching a surface that has the virus on it and then touching their face before washing their hands.

"RSV can spread very easily. It's a virus that can spread in very similar mechanisms, modalities as other respiratory viruses: cough sneeze," Brownstein told ABC News. "It can spread touching contaminated objects, such as doorknobs, but generally speaking, it's transmission via air."

Similar symptoms for babies, toddlers, kids and adults

After people are exposed to RSV, symptoms usually take between four to six days to appear, according to the CDC.

They may include coughing, sneezing, runny nose, fever, wheezing and a decrease in appetite. The CDC said these symptoms usually appear in stages rather than all at once.

Symptoms for babies, toddlers, children and adults are relatively the same.

With babies, they might also develop symptoms including irritability, decreased activity and breathing difficulties, according to the federal health agency.

"For the smallest kids, we really start thinking about RSV when small children present with what we call bronchiolitis, and this is really a pediatric type of respiratory inflammation that affects the smallest airways of the lungs and it can cause problems for the smallest babies, because their size makes them most susceptible to this type of inflammation," Dr. Jade Cobern, a pediatrician in the neonatal intensive care unit at Johns Hopkins, told ABC News.

Cobern said this is not common for children above the age of 2 because their lungs are bigger, and their bodies are more easily able to adapt to this type of inflammation.

Influenza vs. RSV symptoms

Because RSV is often mild and the symptoms resemble those of other viruses, experts said it can be hard to tell if someone is infected with influenza, for example, compared to RSV.

"You wouldn't necessarily know you have RSV," Cobern said.

There are some minor differences. RSV symptoms typically come on gradually, while influenza symptoms come on more suddenly, experts said.

Additionally, it's rare for RSV to result in nausea, vomiting or diarrhea, while it is sometimes common with the flu, although more so in children than adults.

No specific treatments available

Currently, no medications are specifically developed to treat RSV, with most infections resolving within a week.

"All of these [respiratory] viruses are very similar, and of course, the treatments are about the same," Brownstein said. "If you're older and healthier with no underlying conditions. It's all about getting plenty of rest and fluids."

Both Brownstein and Cobern said antibiotics cannot be used to treat RSV so, even in serious cases, treatment would consist of fluids, supplemental oxygen or -- if needed -- ventilation.

Experts said you should call your health care provider or seek medical attention if you or your child is struggling to breathe, not drinking enough fluids or if symptoms are worsening.

Elderly and maternal RSV vaccines, shots for newborns

"It's a really exciting time for RSV prevention," Cobern said. "We have more tools today than we've ever had in the prevention of RSV, and this is for multiple populations."

For adults over age 60, two vaccines are available. For babies under 8 months old, there are two monoclonal antibody shots available, which are a bit different than a vaccine but still provide protection.

Certain babies and toddlers between 8 months and 19 months entering their second RSV season are recommended to receive an antibody shot.

As of Dec. 1, 14% of adults over age 60 have received the RSV vaccine, CDC director Dr. Mandy Cohen said during a press conference Thursday.

There is also a maternal RSV vaccine, which is given to pregnant mothers in the third trimester between 32 weeks' and 36 week's gestation.

"It is designed to actually give antibodies to the baby during pregnancy that they then have through the first six months of life," Cobern said. "So, it doesn't work forever for the babies, but it does pass on some antibody protection, which is great because we really see the highest risk complications in our newborns and our very young babies who are less than six months old."