How common is RSV in infants?



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RSV stands for Respiratory Syncytial Virus.

Respiratory syncytial virus, or RSV, is a common, highly contagious respiratory virus that usually causes mild, cold-like

symptoms, transmission of which occurs through the nasopharyngeal or conjunctival mucosa with respiratory secretions

from infected individuals. Most people recover in a week or two, but RSV can be serious, especially for infants and older

adults. Healthy infants with no underlying conditions can end up in the Intensive Care Unit due to RSV. It is the common

cause of bronchiolitis (inflammation of the small airways in the lungs) and pneumonia (infection of the lungs) in children

younger than1 year of age in the United States (Center of Disease Control and Prevention)

RSV is seasonal, infections of which peaks at certain periods of the year, which is typically at the later part of the Fall

Season and all through the Winter, and early part of the Spring.


People infected with RSV usually show symptoms within4 to 6 days after getting infected. Symptoms of RSV infection

usually include:

  • Runny nose
  • Decrease in appetite
  • Coughing
  • Sneezing
  • Fever
  • Wheezing

While RSV causes cold-like symptoms in some infants. It can progress to more serious disease in others.

At the first 2 days, droplets containing RSV from infected contact enters the nose and the mucosal surfaces of the eyes.

There is usually no signs or symptoms at this point yet.

At days 3 through 5, progressing runny nose, carrying RSV to lower respiratory tract cells. Signs and symptoms may include

congestion, runny nose, fever, irritability and poor feeding.

At days 6 through 8, the infection travels and progressed deeper through the lungs, infecting the bronchioles and alveoli,

causing bronchiolitis and/or pneumonia. Symptoms may include cough, increase thickened secretions, rapidly developing

difficulty in breathing, wheezing, and/or grunting noises, flaring of nostrils, with labored

These symptoms usually appear in stages and not all at once. In very young infants with RSV, the symptoms may be

irritability, decreased activity, and breathing difficulties.

Almost all children will have had an RSV infection by their second birthday.


Call your healthcare professional if you or your child is having difficulty breathing, not drinking enough fluids, or experiencing worsening symptoms.


Care and Treatment

Most RSV infections go away on their own in a week or two without treatment. Antibiotics are not used on RSV as

antibiotics work only against bacteria. RSV is a virus.

The use of over-the-counter fever reducers and pain relievers to manage the symptoms. Check with your doctor if you

are not sure if an over-the-counter product is safe to give to your child. Your doctor may also suggest nasal saline drops

or suctioning to clear nasal congestion.

Some might need treatment in a hospital where they can be watched closely and get supportive treatment in a hospital

where they can be watched closely and get supportive treatment as intravenous fluids to prevent dehydration, and

humidified oxygen for any breathing problems.

Take steps to relieve symptoms

  • Manage fever and pain with over-the-counter fever reducers and pain relievers, such as acetaminophen or ibuprofen. (Never give aspirin to children.)
  • Drink enough fluids. It is important for people with RSV infection to drink enough fluids to prevent dehydration (loss of fluids).
  • Talk to your healthcare provider before giving your child nonprescription cold medicines. Some medicines contain ingredients that are not good for children.


RSV can cause more serious health problems

RSV can also cause more severe infections such as bronchiolitis, an inflammation of the small airways in the lungs, and

pneumonia, an infection of the lungs. It is the most common cause of bronchiolitis and pneumonia in children younger than

1 year of age.

Healthy adults and infants infected with RSV do not usually need to be hospitalized. But some people with RSV infection,

especially older adults and infants younger than 6 months of age, may need to be hospitalized if they are having trouble

breathing or are dehydrated. In most severe cases, a person may require additional oxygen, or IV fluids (if they can’t eat

or drink enough), or intubation (have a breathing tube inserted through the mouth and down to the airway) with mechanical

ventilation (a machine to help a person breathe). In most of these cases, hospitalization only lasts a few days.

Respiratory Syncytial Virus (RSV) Tests

There are two types of tests commonly used to diagnose RSV infections:

  • Rapid RSV Antigen tests are the most common test for RSV. They check a fluid sample from your nose for certain proteins from the RSV virus called antigens. RSV antigens trigger your immune system to attack the virus. Rapid antigen tests can provide results in an hour or less.
  • Molecular tests called RT-PCR (polymerase chain reaction) tests look for genetic material from the RSV virus in your sample. These tests can find smaller amounts of the virus than antigen tests. So, RT-PCR tests may be used for older children and adults who tend to have less of the virus in their noses than infants and younger children. Samples are usually sent to a lab for testing. In certain cases, your provider may order a molecular test calleda respiratory pathogens panel. This test check for RSV and other respiratory viruses and bacterial infections at the same time.


What happens during an RSV test?

RSV test samples should be taken during the first days after the symptoms started The amount of the virus in your nose

decrease over time, which may make the test results less accurate.

Tests to diagnose RSV are done on a sample of fluid from your nose. There are different ways to collect the sample:

  • Nasal aspirate or wash. This is the most common way to collect a sample for RSV testing to do a nasal aspirate, a health care professional will insert a saline solution (salt water) into your nose and remove it with a gentle suction.
  • Nasal swab test. A health care professional will use a special swab to take a sample from your nos

At-home test kits are available to buy without prescription. The tests check for RSV, flu and COVID-19 using one sample.
The kit includes a nasal swab to collect the sample to send to a lab for testing. Talk with your provider about using an at-

home test.

Blood tests are not usually used to diagnose RSV, but they can show if a recent illness was an RSV infection. If there is an outbreak of RSV in the community, the public officials may use blood tests.



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All The Best,                                                                                                                                                                                                            

Maria Teresa 

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