Why rsv increase?

In other words, RSV has arrived early this year and is impacting hospitals, urgent care centers and clinics in numerous locations across the U.S. Knowing a bit about the disease, how to protect oneself and one's children—and when to seek treatment—are key to enduring this unwelcome seasonal guest.

RSV is an enveloped single-stranded RNA virus of the genus  Orthopneumovirus, family  Pneumoviridae. It was first identified in 1956 when a colony of chimpanzees used for polio research at the Walter Reed Army Institute for Research in Washington, D.C. developed runny noses caused by inflammation (i.e., coryza). At the time, the etiologic agent was named chimpanzee coryza agent (CCA). One year later, in 1957, a "new" virus that caused severe respiratory illness in infants was found in Baltimore and discovered to be identical to CCA. The pathogen was renamed Respiratory Syncytial Virus, since the virus causes cells to fuse with neighboring cells, creating multinucleated syncytia (single cells containing multiple nuclei).

Symptoms typically include fever, runny or stuffy nose, cough, dyspnea (shortness of breath) and wheezing. Severe infections can lead to bronchiolitis (inflamed airways clogged with mucus) and pneumonia. RSV mortality is associated with approximately 100 underlying respiratory deaths each year in children younger than 1 year, posing a greater risk to infants than influenza.

RSV is primarily spread from human-to-human though respiratory droplets when a person coughs or sneezes, and through direct contact to the eyes or nose after touching a contaminated surface or object. RSV can survive for up to 12 hours on hard, non-porous surfaces, but it typically persists for shorter amounts of time on soft surfaces, such as tissues and hands.

​The incubation period for RSV is 3–5 days, and people can be contagious for 3-8 days after infection. It is even possible to be contagious 1-2 days before symptoms appear. Virus shedding can last up to 4 weeks in infants and young children, elderly people and people with weakened immune systems.

With numerous respiratory viruses circulating, it can be difficult to tell the difference between influenza, COVID-19, RSV and other respiratory viruses in children and infants. Parents and caregivers should stay alert for emergency warning signs. Seek medical attention right away if any of the following symptoms occur: difficulty breathing, blue lips or face, irritability, decreased activity, decreased appetite and apnea.

Although RSV is not a new virus, many have not heard of but have likely been infected with it at some point in their lifetimes. Almost all children get an RSV infection by the time they are 2 years old, but RSV isn’t just a virus impacting young children—older adults can still be at risk for severe infection. Age, chronic health conditions and weakened immune systems are all risk factors for the disease.

Historically, in the U.S., RSV infection results in the following annual statistics:

Restrictive, and unprecedented, public health measures—mask use, social distancing, increased attention to hand hygiene—adopted throughout 2020 and 2021 blunted the transmission of respiratory viruses, including RSV. In fact, flu and other cold viruses virtually disappeared. However, as restrictions were lifted, RSV returned with full force in June 2021, eventually decreased as January 2022 approached and slightly increased again in summer 2022.

Now, healthcare workers are reporting spikes in RSV cases earlier than expected for the Fall 2022-Spring 2023 season, and the exponential increases are impacting healthcare facilities that are already grappling with rising cases of influenza and COVID-19. If one looks at the CDC data, the increase in RSV cases began as early as late August and early September of 2022 but surged [~5 fold] in November.

As of Nov. 12th, 2022, the CDC reported over 8,000 positive RSV antigen and PCR tests, compared to around 4,500 last November. Scientists are referring to this as “immunity gap” or “immunity debt,” a term proposed to describe the issue of protective immunity from global COVID-19 pandemic mitigation measures over extended periods of low exposure to a given pathogen, leaving a greater proportion of the population susceptible to the disease.

As a result, healthcare facilities across the U.S. are being stretched and some have even activated their incident command systems—an emergency management approach to assess and monitor trends and manage resources.

One preventative measure is Palivizumab (Synagis®) which is the only FDA-approved medication to help protect high-risk babies from severe RSV disease. This monoclonal antibody has been approved for preemies (babies born at or before 35 weeks) and infants who are 6 months of age or less at the beginning of RSV season. The medication is not a vaccine but works as a monthly dose of protective antibodies during RSV season.

An exciting development by Pfizer reports positive top-line data from the Phase 3 clinical trial investigating its bivalent RSV prefusion vaccine candidate, RSVpreF, when administered to pregnant participants to help protect their infants from RSV disease after birth. The study is ongoing and has received Breakthrough Therapy Designation and fast-track status from the FDA.

Lastly, common public health measures that helped keep us safe from COVID-19 over the past 2+ years also help limit the spread of other viruses and shouldn’t be forgotten. A few of these easily implemented practices are listed below:

As temperatures drop and people move indoors, RSV (and other respiratory viruses) are expected to increase. Practicing and promoting those simple everyday preventive measures plays an important role in keeping us safe. We can only hope that lessons from COVID-19 can be applied for this threat as well.

Temperatures are dropping and the risk of COVID-19 and influenza are up. And for the last few months, patients with a different malady — respiratory syncytial virus, known as RSV — have been overwhelming hospitals. Public health officials warn that come winter there could be a "tripledemic."

The unusually high number of RSV infections so early in the year are already pushing hospitals to capacity. In normal years, RSV sends thousands of children to the hospital over fall and winter, but for the second year in a row experts have seen an unprecedented spike in the number of cases beginning during the summer months.

While RSV mostly manifests as a mild illness with cold-like symptoms in adults, it can cause pneumonia and bronchiolitis in very young children. It can be life-threatening in infants and older adults.

But just how concerned should parents be? Here are answers to some of the most common questions about the RSV infection, who is most at risk and what might be causing this year's outbreak.

While it may be too early to know for sure, health experts agree that the earlier-than-usual surges are a consequence of the broad lifting of COVID-19 precautions, which served to protect the public from a variety of viruses.

"When the pandemic hit the U.S. in March 2020, we saw the rates of all viruses plummet," Dr. Vandana Madhavan, director of advanced pediatrics at Mass General Brigham in Boston, told NPR. That was largely due to people staying indoors, wearing masks and frequently washing or sanitizing their hands, she added.

Once restrictions began to be loosened in the spring of 2021, health experts began seeing odd patterns of circulation of these respiratory viruses. This year, the return to pre-COVID social activities and interactions, travel and in-class teaching has led to another dangerous spike, Madhavan explained.

There's something else going on, she added. Very young children born just before or during the pandemic did not benefit from regular or early exposure to common viruses, including RSV, which would have helped build up an immunity.

"We've had this whole cohort of young children who haven't had that usual constant exposure to viruses at day care or in preschool or out in the community. And so now they're getting exposed and it's hitting them really hard," Madhavan said.

Those conditions have led to what some doctors are calling an unprecedented number of infants and children in emergency rooms and pediatric intensive care units across the country.

"My hope is that this is not the new normal," Madhavan said on Friday. "But for this year, it is concerning because it's still only late October and we don't know what we're going to see as we head deeper into fall and especially this winter."

Nearly all children get an RSV infection by the time they are 2 years old, according to the Centers for Disease Control and Prevention. In most cases, it will cause mild, cold-like symptoms, much as it does in the vast majority of healthy adults. But it can also cause severe bronchitis or pneumonia in very young children, particularly infants and those under the age of 5.

The problem is that their small lungs and muscles can't muster up the power to cough up or sneeze out the increased secretions and mucus caused in their airways.

"They have a hard time getting out that excess fluid and that's why they have trouble breathing which then that leads to problems eating and drinking," Madhavan said.

RSV treatments in such cases can include oxygen support, suctioning, and IV fluids.

According to the CDC's data, each year approximately 58,000 children under 5 are hospitalized for RSV. The next most vulnerable group are adults over 65, in whom the infection causes 14,000 deaths a year.

Health officials say handwashing, staying hydrated, keeping hands away from the face and disinfecting surfaces help to stave off RSV or keep it from becoming a serious illness.

But for those with newborns or kids under one, Madhavan said the best thing to do is to keep children away from adults who have been recently sick.

She suggested not being shy about grilling others about how they've been feeling. "A lot of the time when people ask that question, the person on the other end really only thinks to mention anything if they've been really sick, so they don't think to mention if they've had a minor cold." But that could become a serious case of RSV for an infant or a toddler, she added.

Madhavan said the effective way for children and adults to try to stay healthy throughout the remaining fall and winter months, is to get updated COVID booster and influenza vaccines.

Anyone over six months old can get the flu vaccine. Madhavan noted that it takes a couple of weeks for the shot's full protection to take effect. "If a child is under eight and has never gotten influenza vaccine before, they need two doses one month apart before getting full protection two weeks after that second dose," she added.

The COVID bivalent boosters for people 5 and older became available in September. And children over six months can get any of the three available COVID-19 vaccines. "Don't wait until we're in the middle of another COVID wave to get the booster," Madhavan warns.

There is no RSV vaccine yet, although there are many in development.

There is, however, a treatment called palivizumab that is available to high-risk infants. It is an injection that can be given to premies and other babies born with certain lung or heart conditions who are at high risk for severe RSV disease. It is administered once a month throughout the RSV season.

"It is not a vaccine in that it doesn't help the immune system make longer term immune protection, but it keeps giving antibody against RSV every month during those high-risk periods for those high-risk children to give them additional protection," Madhavan explained.

Still, Madhavan stressed, palivizumab is not routinely given to all children. Part of that is due to the possible, more serious side effects associated with the drug, which include swelling of the throat, difficult or rapid breathing, muscle weakness, and unresponsiveness.

Hospitals, emergency rooms and pediatric ICUs across the country have been teeming with RSV patients for weeks now. So it's important to know when to head for the ER and when it might be a better, healthier idea to stay home, Madhavan said.

She strongly discourages people from heading to the ER to get tested for RSV or other respiratory viruses.

"If you think you or your child has it, it's best to pick up the phone and call your doctor or nurse rather than coming into a setting that might mean a long wait or might mean exposure to other viruses that your child and family don't have and can have risks on their own," she said.

Normally a cold-weather epidemic, RSV usually spreads among young children, straining hospitals in the Northern Hemisphere as early as late October and lasting until the cold and flu season wanes in spring.

The COVID-19 pandemic appears to have upended this rhythm in one country and possibly others.

Weinberger, together with YSPH PhD student Zhe Zheng, Associate Professor Virginia Pitzer, ScD, and an international team of researchers, recently published a study suggesting that a surge of RSV infections began in the Netherlands last summer and has lingered in the country ever since.

The pre-print study, produced collaboratively among epidemiologists in the U.S., France, and the Netherlands, has yet to be peer-reviewed. But its findings show that non-pharmaceutical interventions which were used to stop the spread of Covid-19, like social distancing and school closures, may have helped create a so-called “immunity debt” that is impacting children today.

“We saw all around the world that RSV basically disappeared [during COVID] — it’s one of the most common causes of hospitalization in young patients, and it was completely eliminated for over a year, which was really remarkable,” Weinberger said. “Our colleagues in the Netherlands had the foresight when this unusual pattern started to put excellent surveillance into place to monitor the occurrence of RSV around the country.”

The change in infection rates isn’t entirely a bad thing, Weinberger cautions. Even though RSV-related hospitalizations are now climbing in the United States and abroad, the fact that many children are being exposed to the illness later in life could lead to less severe infections overall.

“We have seen an age shift in the RSV epidemic recently,” Weinberger said. “Kids that were coming in this year and last year are on average a little bit older than the kids who were coming in before the pandemic, and we think that’s partially because they’ve never been exposed before. That’s actually better because older kids are less susceptible to very severe outcomes from RSV.”

As part of their analysis, the Dutch team, led by Professor Louis Bont, collected real-time pediatric RSV illness data from 46 hospitals across the Netherlands from May 2021 to September 2022. Combined with existing surveillance data on RSV illnesses by patient age, and analyzed with mathematical models, their analysis revealed an “unusual” RSV epidemic pattern within the country, the study’s authors said.

Graphs in their paper show a dagger-like spike in RSV infections almost immediately following the end of a COVID-19 lockdown period in June 2021, followed by a prolonged period of continuous transmission of RSV at mid-to-high levels through July 2022.

These occurrences may be partially explained by waning population immunity, the researchers write — an “immunity debt” — which the Netherlands is only now catching up on.

“Normally, you’re exposed to RSV during the winter and your immunity gets boosted a little bit as you get re-exposed and your immune system gets recharged,” Weinberger said. “But we had this long period where people weren’t getting exposed, where we had more people who had never seen RSV, and also people who hadn’t seen RSV in a long time who were more susceptible to infections. A combination of those things, we think, led to this sustained transmission of RSV over quite a long period.”

RSV is a common respiratory virus that infects the nose, throat, lungs, and breathing passages. RSV is so widespread that almost all children will have had an RSV infection by their 2nd birthday. RSV can be serious and can lead to severe illness among both children and older adults. While certain groups (including premature and infants ≤6 months, individuals with chronic heart or lung disease, immunocompromised individuals, and adults age 65+), are at increased risk for severe disease, the potential for dangerous complications is a concern among all age groups.

Although RSV cases in the US dropped as the COVID-19 pandemic caused schools, daycares, and businesses to shut down, hospitals are now seeing increased numbers of RSV infection in addition to cases of flu and COVID-19, making it particularly important to take precautions against circulating viruses.

The best ways to help prevent the spread of RSV (and other respiratory viruses) include the following:

Researchers are currently working to develop new tools to prevent and treat RSV such as vaccines and monoclonal antibodies targeted for specific populations, including infants and young children, older adults, pregnant women, and adults with compromised immune systems.

Is the US Facing a Potential ‘Tripledemic’ of Flu, RSV, and COVID-19? According to the Centers for Disease Control and Prevention, respiratory illnesses are appearing earlier, and in more people, than in recent years. Source: ABC News

The RSV Surge Didn’t Come Out of Nowhere, but Gaps in Data Made it Tougher to Predict: The US is dealing with a unique season of respiratory virus transmission: Flu cases are on the rise earlier than usual, and RSV case rates are extra high, even after an “unprecedented” early surge this summer. Source: CNN

These Are the Signs and Symptoms of Flu, RSV, and COVID-19 in Kids: All usually begin as upper respiratory infections, making it difficult for parents to know which virus they are dealing with early on. Source: NBC News

Hospitals Are Worried about Child RSV This Year. Here’s What To Know: Most of the focus has been on children getting RSV and filling up pediatric units, but the elderly are also susceptible to the virus. Expert advice remains the same: Wash your hands, clean surfaces, and seek medical care if someone isn’t doing well. Source: The Washington Post

RSV cases fell dramatically two years ago as the pandemic shut down schools, day cares and businesses. With restrictions easing in the summer of 2021, doctors saw an alarming increase in what is normally a fall and winter virus.

Now, it’s back again. And doctors are bracing for the possibility that RSV, flu and COVID-19 could combine to stress hospitals.

“I’m calling it an emergency,” said Dr. Juan Salazar of Connecticut Children’s Hospital, where RSV has caused a shuffling of patients into playrooms and other spaces not normally used for beds. The institution explored using a National Guard field hospital, but has set aside that option for now.

A look at RSV and what the recent surge may mean:

It stands for respiratory syncytial virus, a common cause of mild cold-like symptoms such as runny nose, cough and fever. Nearly all U.S. children normally catch an RSV infection by age 2.

People infected are usually contagious for three to eight days. Babies and people with weakened immune systems can spread RSV for up to four weeks. There is no vaccine for it, though several candidates are in testing.

Everyone can get RSV. But it causes the most threat to infants, older adults and other vulnerable people, who can get serious airway and lung infections.

READ MORE: Should I get the new COVID-19 booster? Here’s what you need to know

Among U.S. kids under age 5, RSV typically leads to 58,000 hospitalizations and up to 500 deaths in a year. For adults 65 and older, RSV causes 177,000 hospitalizations and 14,000 deaths yearly.

For babies, the struggle to breathe can interfere with eating. “And that’s really when we start to worry,” said Dr. Melanie Kitagawa of Texas Children’s Hospital in Houston, where more than 40 children have RSV.

“They’re breathing fast, breathing deep. We see them using muscles in their chest to help them breathe,” Kitagawa said. “These are kids who are having difficulty taking a bottle because their breathing is being impacted and they can’t coordinate both at once.”

The virus is encountering a highly vulnerable population of babies and children who were sheltered from common bugs during the pandemic lockdowns.

Immune systems might not be as prepared to fight the virus after more than two years of masking, which offered protection, according to Dr. Elizabeth Mack of Medical University of South Carolina.

“South Carolina is drowning in RSV,” Mack said in a news release. The surge arrived earlier this year than normal, she said.

For babies, their mothers may not have been infected with RSV during pregnancy, which could have given the children some immunity.

U.S. health officials have noted a rise this month in national reports of respiratory illnesses, which they say is at least partly due to the early spread of flu in much of the South.

Last week, more than 7,000 tests came back positive for RSV, according to CDC figures. That’s more than in previous surges.

There’s no specific treatment, so it’s a matter of managing symptoms and letting the virus run its course. Doctors may prescribe oral steroids or an inhaler to make breathing easier.

In serious cases, patients in the hospital may get oxygen, a breathing tube or a ventilator.

Prevent the spread of viruses by washing hands thoroughly and staying home when you’re sick.

During RSV season, an injection of an antibody-based medicine is sometimes prescribed to protect premature infants and other very vulnerable babies.

If you’re worried your child is having a severe breathing problem, “do not hesitate” to go to an emergency department or call 911, said Dr. Russell Migita of Seattle Children’s Hospital, where RSV is on the rise.

For less severe medical problems, Migita said, call your regular health care provider for advice, use telehealth or go to urgent care.

In Chicago on Saturday, Dr. Juanita Mora saw a family of five kids all with RSV, ranging from a 3-year-old to a teenager. Fearing what’s ahead this winter, she’s telling everyone to get a flu shot and a COVID-19 booster.