SALT-MEERSTAD – While the COVID-19 transmission rate is still declining, two diseases that normally result in many pediatric hospitalizations are virtually non-existent throughout the winter.
Respiratory synthesis virus, or RSV, and influenza resulted in virtually no hospitalizations in the Primary Children’s Hospital. This is a welcome surprise for pediatric specialists who typically receive 80 to 120 RSV admissions and dozens of intensive care units per week, in addition to hundreds of annual flu hospitalizations.
“It really is, remarkably,” said dr. Andrew Pavia, a pediatric infectious disease specialist at Primary Children’s Hospital, said during a press briefing on Monday about the trends in pediatric hospitalizations for both viruses.
The hospital has seen more cases of the rare complication of SARS-CoV-2, called multisystem inflammatory syndrome, or MIS-C, as flu or RSV. It is estimated that approximately 75 MIS-C cases have been treated in hospital over the past few months.
RSV is something that affects ‘virtually every child’ in their first few years after birth. This usually leads to coughing and wheezing. some children get shortness of breath and they eventually need to be hospitalized.
Adults older than 75 also suffer from RSV. Pavia said it eventually results in much older cases of pneumonia. Older children and adults usually experience cold-like symptoms.
Primary Children’s Hospital has not yet reported a single RSV hospitalization during the regular season.
“We’re seeing something I’ve never seen in the last 35 years,” Pavia said. “If you go back to history, it didn’t really happen except shortly after the 2009 flu pandemic.”
Then there is the flu, which often strikes hundreds of thousands of Americans each year. To date, the Centers for Disease Control and Prevention has reported just under 1,600 total confirmed flu cases in the U.S. due to nearly 1 million trials.
The CDC reports that all 50 states and Puerto Rico have ‘minimal’ flu trends. Less than two dozen new cases have been reported in the past week.
These are similar almost unheard of trends in Utah.
The Utah Department of Health’s weekly flu panel shows that until February 13, there were only 13 total hospitalizations due to flu. There were 1310 total hospitalizations for flu last year.
Pavia said there was one hospitalization in children compared to a few hundred that would normally occur at this point in the flu season.
Recently, there have been so few cases that there were not enough data to post the latest positive percentage for flu. The numbers on a chart compared to previous years are staggering.
It is unknown at this time what he will do after leaving the post. One theory for the flu is that there were so few cases during the winter in the Southern Hemisphere and that travel restrictions were in place so that the flu could not really be transmitted from the world, Pavia explained. The other is that masks and other guidelines to prevent the spread of COVID-19 work to stop other respiratory diseases.
RSV, on the other hand, is ‘somewhat more confusing’, Pavia added.
“RSV does not disappear completely every summer. There are cases in the warmer climate all year round,” he said. “Places like New Orleans and Miami have an RSV all year round, so you’d think it would be our reservoir that would make it boring and RSV would pop up this winter, but it doesn’t happen.”
Masking, keeping children at home and keeping babies away from less possible exposure to RSV, are theories that, according to Pavia, could explain its decline. Still, experts have no idea why it is ‘practically zero’ not only in Utah but across the country as well.
Why RSV and flu can come “roaring back”
However, the good news now has a caveat. Australian doctors have reported similar trends for both flu and RSV during the winter in the Southern Hemisphere. Then the RSV numbers rose sharply before the summer of the Southern Hemisphere began.
Australian Broadcasting Corporation reported last December that RSV business at all ages turned off from near zero in the winter months of New South Wales. By November, there were just over 1,600 cases in the month.
“It is very likely that, if both flu and RSV are gone for a while, more people will be susceptible to it,” Pavia said. “So when it comes down to it, it spreads more dramatically and we see worse diseases.”
The reason why flu returns more violently is that flu is adapting and that it is difficult to know which strain of the virus will come from. The decline of RSV, on the other hand, means that there is a larger group of babies who would arrive later this year or next year because they did not experience it now.
“RSV is going to do something really weird when it comes back,” Pavia added. “It simply came to our notice then. Our feeling is that it will roar again and that we will have a bad RSV year when it comes back. ‘