Respiratory Syncytial Virus (RSV): What You Should Know About the Current Outbreak

If you have young children, if you watch the news, or if you have seen your pediatrician or family physician recently, then you probably have heard of RSV. Despite the way that some news media are talking about it, RSV not a new disease. It’s one of the main respiratory infections that pediatricians see and treat. It’s a virus that has been around for a very long time, it strikes each year from autumn through winter, and it has hit hard this season. This follows two years of the COVID-19 pandemic, when isolation measures may have kept RSV at bay. RSV is notorious for striking children below the age of five years, especially infants, and those who were born preterm are at particular risk. But the virus can also cause disease in people of all ages. Elderly people are in particular danger, especially if they have other lung conditions, or immune system conditions, or if they reside in nursing homes. So you should think of RSV as an infectious disease that typically strikes the the very young and the very old. Since the focus of The Pulse is on new parents, we’ll concentrate on the infant health aspects of RSV, but keep in mind that RSV infection can be even more dangerous than influenza to the health and lives of your elderly parents or grandparents and possibly of equal danger to them as infection with SARS-CoV2, the virus that causes COVID-19. We can even say, today, that RSV, potentially, is even more dangerous to elderly people than SARS-CoV2, because we have effective vaccines against the latter, whereas vaccines against RSV are only going through testing and are not yet on the market.

In news reports, you may be hearing some scary things, such as that neonatal intensive care units (NICUs) and pediatric intensive care units (PICUs) are overwhelmed in certain cities and regions. Sadly, this is true. Planetwide, RSV kills about 100,000 children below age five each year. This makes RSV the number one respiratory cause of death in young children and also the number two overall cause of death in young children, after malaria. As for hospitalizations, in 2019, the year before the pandemic hit, RSV sent about 3.6 million people to the hospital planetwide. In developed countries, the numbers are better, but still disturbing. A recent paper in The Lancet reports 1 in every 56 healthy infants born to term (37 weeks gestation or later) being hospitalized for RSV, and that’s in five high income sites, each in a different European country. Also, each winter in the United States, RSV kills 100-300 children below age five, along with 6,000 – 10,000 adults ages 65 and older.

The pediatric mortality numbers for RSV are thus comparable with those for influenza and COVID-19 and healthcare providers are concerned that we are facing a kind of tridemic: an epidemic of COVID-19, flu, and RSV, which could include children suffering from all three. While this is a reason to concerned, it’s also important to maintain a perspective. You should be on the lookout for symptoms to discuss with your pediatrician, but also keep in mind that while RSV can take a severe course and threaten life, often it is mild and does not require hospitalization. In fact, most people are infected with RSV by the age of two. It’s likely that you once had RSV and that you don’t know about it. Nevertheless, RSV always requires for your doctor to know about it. Consequently, if your child becomes ill, even if it looks like just a cold, contact healthcare providers and discuss it. With this in mind, let’s take a deep dive into RSV, beginning with what it is.

RSV stands for respiratory syncytial virus. Initially, this may strike you as a complicated term, but you already know two of the words. The word respiratory tells you that we’re talking about an illness in the respiratory tract. Symptoms of RSV actually can start in the upper respiratory tract, in other words like a cold with a sniffling runny nose, but the danger is that it classically affects the lower respiratory tract. Those are the cases that often require hospitalization. Of course, the word virus tells you that the infectious agent is a virus and not a different type of infectious agent. It’s a virus, just as influenza and SARS-CoV2 are viruses.

As for the word syncytial, this word derives from the fact that the virus causes certain cells to fuse together into a syncytium when cultured in the laboratory. A syncytium is a kind of supercell, a mass of cytoplasm with a large number of nuclei, because it forms from cells that were previously separate. The parts of the lower respiratory tract that RSC disrupts are the airways. This causes bronchiolitis, meaning inflammation of the smallest airways, which are called bronchioles. It also can cause pneumonia, which is inflammation of the alveoli, the air sacs, where the exchange of gases between the air and blood occurs. And yes, it’s possible to have bronchiolitis and pneumonia at the same time.

While RSV is a problem up through the age of five years, infancy is when it’s a particular problem. Preterm infants are especially vulnerable. The risk of getting severely sick from RSV decreases day by day, week by week, year by year (until you get very old, when the risk rises from the age of 65).

Vaccines to fight RSV are going through clinical trials and scientists think that immunizing women against RSV before they get pregnant will prove effective in protecting neonates. Currently there is no licensed RSV vaccine, but for infants at extreme risk of severe RSV —those who were born preterm at 35 weeks gestation or sooner and who are under the age of 6 months at the beginning of RSV season (which starts in the autumn)— there is an immune treatment that is given for protection. It’s an intravenous immunoglobulin, a monoclonal antibody, called palivizumab. It must be administered every 28-30 days through the RSV season.

In contrast with vaccination, the antibody treatment is what doctors call passive immunity. It’s not the kind of immunity that the child’s immune system produces and maintains. It’s immunity from an external source, like the immunity that newborns have against various diseases (but not usually for RSV) by way of antibodies that they obtain from the mother before birth and like the immunity that nursing infants have. The passive immunity from palivizumab is exactly like the immunity that certain other monoclonal antibody treatments, such as tixagevimab/cilgavimab (EvusheldTM), provide high risk people against COVID-19. Other than antibody protection for infants at high risk, the way to prevent RSV disease is to take precautions against spread. This means masking when people have colds at home and are handling infants and of course hand-washing.

Along with respiratory symptoms that can look like a cold, RSV often causes fever. Any time that your newborn infant has a fever, the child should be seen by a physician. To treat the fever when you are preparing to bring your child to a doctor, or waiting overnight, you can give infant acetaminophen. Do NOT give aspirin, as this can cause a dangerous complication called Reye syndrome that can harm organs, such as the brain and liver.

On account of the bronchiolitis that occurs in serious cases of RSV, infants with RSV tend to have very noisy breathing. There are wheezing sounds, often audible even without a stethoscope. Treatment for RSV is supportive, consisting of measure such as hydration, both in patients with mild cases who can recover at home and in cases that need hospitalization. Certain children with RSV can benefit from treatment with bronchodilators, agents that they breathe in to open their airways, but these should not be given in most cases. In more serious cases, the infants need oxygen and in severe cases they need special ventilatory support, such as high flow oxygen, continuous positive airway pressure (CPAP), and other treatments that are given in NICU and PICU settings.

David Warmflash
Dr. David Warmflash is a science communicator and physician with a research background in astrobiology and space medicine. He has completed research fellowships at NASA Johnson Space Center, the University of Pennsylvania, and Brandeis University. Since 2002, he has been collaborating with The Planetary Society on experiments helping us to understand the effects of deep space radiation on life forms, and since 2011 has worked nearly full time in medical writing and science journalism. His focus area includes the emergence of new biotechnologies and their impact on biomedicine, public health, and society.

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