For months, public health experts in the U.S. have been warning of an impending tidal wave of respiratory illness — an ominously termed “tripledemic” with sky-high cases of respiratory syncytial virus (RSV), influenza and COVID in the same season. And early, steep spikes of both RSV and the flu, combined with a burgeoning swell of COVID cases, indicate that this moment has now arrived in Maryland and most other states.

Dr. J. David Gatz, emergency department medical director at the University of Maryland Medical Center, says the term tripledemic indeed “captures the situation we’re in” now, still early in the respiratory illness season, with three viruses already “surging more or less at the same time.”

And the early severity of viral surges, he says, underscores the need to take measures to slow the spread of illness over the holidays.

Dr. Susan Lipton, chief of the department of pediatric infectious diseases at Sinai Hospital, says it all started when RSV — a common seasonal respiratory virus with potential to cause severe illness in children, particularly those under 3 — ”showed up eight weeks early” in August and September. Cases skyrocketed through the month of October and peaked at the end with 263 hospitalized for the virus statewide.

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RSV hospitalizations in Maryland for 2022-2023 and five previous seasons. Updated December 3, 2022.
RSV hospitalizations in Maryland for 2022-2023 and five previous seasons. Updated Dec. 3, 2022. (Maryland Department of Health)

October also marked the beginning of a rise in flu cases, Lipton says, about 12 weeks earlier than normal.

RSV hospitalizations in Maryland have decreased by over 70% in the last five weeks, with 76 people admitted as of Dec. 3, or about half of peak level for the last comparable, pre-COVID virus season in 2019 to 2020. Still, no one knows whether subsequent peaks will occur later this season, as has happened in previous years.

Lipton began to be concerned when the only RSV-specific treatment — an expensive monoclonal antibody given to premature infants to prevent severe disease, which is covered by insurance companies starting at the beginning of the season in October — was not available for the first preemies who needed it when RSV emerged in late summer, she says.

RSV can be dangerous for all babies, but especially the premature, Lipton said, because it interferes with cellular production of surfactant, a substance that coats the air sacs in the lungs and makes breathing easier — a critical process in tiny infants whose lungs are underdeveloped. RSV also puts babies at greater risk for crib death, Lipton says, because of the difficulty in breathing that it can cause.

Reduced exposure and immunity to RSV over the last two respiratory virus seasons due to widespread COVID precautions also led to more severe cases in toddlers and older kids, says Lipton, leading to the first “bed crisis” in the beginning of September, when all pediatric ICUs in the area reached capacity and overflow patients had to be housed in the emergency department. Lipton says Sinai has remained at capacity since the initial RSV surge.

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In the meantime, flu has taken center stage. The week of Thanksgiving saw hospitalizations statewide rise to 498 — a number reached in just two of the 10 preceding flu seasons, but not until January or February. Hospitalizations peaked at 380 in February of the 2019 to 2020 season.

Influenza or flu hospitalizations in Maryland for 2022-2023 and three previous seasons. Updated Dec. 8, 2022 (Maryland Department of Health)

Ten flu-related adult deaths have been reported in Maryland so far this season, with half those occurring the week of Thanksgiving. No pediatric deaths have yet occurred.

Nationally, nearly 26,000 people are currently hospitalized for the flu, per the most recent data. So far this season, 120,000 people have been hospitalized and 7,300 have died from the flu nationwide, including 21 children.

Gatz says he’s been seeing mostly flu in the emergency department, with an increase in cases following the Thanksgiving holiday. Many patients will come in having already taken a COVID-19 test, he says, and wondering why they’re feeling terrible despite their negative result. He says the ED does not typically test for RSV in adults, as it will usually cause cold-like symptoms that do not lead to serious illness for them.

Dr. Kathryn Boling, family medicine physician at Mercy Primary Care at Lutherville, says one of her non-elderly adult patients was recently hospitalized and intubated for RSV infection; the patient had an underlying neurologic condition that made them more susceptible to severe illness. Elderly patients also run greater risk of being hospitalized for RSV, Boling says.

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Otherwise, Boling says, she’s been seeing more COVID than flu among her patients lately. She says she fielded about 20 calls on the morning of Thanksgiving from patients who had just tested positive.

State COVID hospitalizations have been steadily increasing over the last month, with 537 people hospitalized on Dec. 8, compared to 420 on Nov. 25. Daily case positivity rates have shot up over the same time period, from 7% of all reported tests that were positive in late November to nearly 11% currently. A handful of COVID deaths have been occurring daily in Maryland over the last few months, with eight deaths on Dec. 7, the last day for which data was available.

Dr. Eric Toner, an emergency department physician and senior scientist in the Johns Hopkins Bloomberg School of Public Health’s Center for Health Security, says he’s “not too worried” about the recent COVID increase.

“I think there is enough immunity in the population that it will blunt a severe surge. The flu season, on the other hand, is pretty impressive,” he says, and could be one to remember.

Boling warns that COVID is more transmissible than flu or RSV because it’s airborne. Virus particles can linger in the air for a couple of hours following a cough, sneeze, or exhalation, she says, and “if you happen to go and stand in that airspace,” you can catch it if you’re susceptible. The flu and RSV are less infectious, Boling says, because they’re transmitted via droplets that tend to settle on surfaces, making their way from someone’s hands into their mouth, nose, or eyes.

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The post-Thanksgiving uptick in respiratory illness foreshadows what could be in store following the winter holidays, the experts say, while highlighting the need for people to take preventive measures.

Lipton says “you can almost make money” on a surge in respiratory viruses occurring after the winter holidays, with cases typically “sky high” about three weeks into January. She believes the nation will see “biphasic” peaks this season, with the first, now-retreating RSV peak mostly affecting children, and a second, post-holiday peak involving flu and possibly COVID primarily impacting the elderly. Lipton predicts this later peak will result in greater numbers of hospitalizations and deaths than were caused by RSV.

Low vaccination rates will contribute to this, Lipton says. A quarter of Marylanders have been vaccinated for flu with roughly equivalent rates among residents of Baltimore City and county. Nationally, just 13% of people 5 years of age and up have received the bivalent COVID booster. That number increases to 34% for those 65 and older.

Lipton and other experts say the number one thing people can do to protect themselves and loved ones against the flu or COVID over the holidays is to get vaccinated if they are eligible. Lipton knows the importance of vaccination firsthand — she put off getting the flu vaccine one year in her mid-20s, contracted influenza, and spent 34 days on life support. She developed Adult Respiratory Distress Syndrome and had to have all toes and fingers amputated except for one due to blood-clotting issues.

Tripledemic infographic. (Baltimore City Health Department)

Dr. Tamara Green, chief medical officer for the Baltimore City Health Department says, “We can’t predict what will happen after the holidays, but if it’s any indication, after Thanksgiving we did see an increase in positive tests for the flu. Hopefully, if people get vaccinated we won’t see another increase or a continuation of the increase.”

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Neither Gatz nor Boling recommend waiting three months after contracting COVID to get the bivalent booster, as the CDC originally said when it was first authorized. “I’m seeing people who get COVID and then a month later they get COVID again. So in my opinion as soon as you’re able to after you are better from being sick, you should get vaccinated,” Boling says, unless you were treated with monoclonal antibodies, in which case you should still wait three months before getting the updated shot.

Late last week, both the FDA and CDC signed off on expanding use of the bivalent vaccine to infants as young as 6 months. It had previously been authorized for children 5 years old and above.

Apart from vaccination, the experts recommend frequent hand washing, masking on public transportation and in crowded areas, and considering testing for illness prior to gathering with others “at extremes of age,” Gatz says, like the very young and the very old, as well as anyone who is immunocompromised.

Above all, Boling says, people should test before visiting loved ones if they have symptoms of respiratory illness, keeping in mind that COVID results may be negative for the first few days, especially if you are vaccinated. If results are still negative a few days later, she says, wear a mask when gathering indoors if you’re still feeling sick.

“COVID can present in any manner of ways,” including having no symptoms, feeling like you have allergies or the flu, or being ‘deathly ill,’” Boling says, “so the only way to know for sure is to test.”

Sarah True was a public health reporter for the Baltimore Banner. She previously worked as a freelance journalist covering healthcare and health policy, and has been both a medical social worker and a health policy analyst in a past life. She holds dual Master’s degrees in public health and social work. 

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