Navigating the Confluence of Respiratory Pathogens: Preparing for the Winter Triple Threat

September 30, 2023

Saskia v. Popescu, PhD, MPH, MA, CIC, FAPIC

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Medical investigators are concerned about a triple threat this winter with COVID-19, influenza, and RSV. Vaccination is crucial, but distribution challenges remain. Wearing masks, hand hygiene, and ventilation is important to prevent infections. Hospitals need comprehensive plans to respond efficiently.

Triple virus outbreak or Tripledemic: Covid-19, influenza, and respiratory syncytial virus (RSV)

The concern of a tripledemic isn’t new to the 2023-2024 winter season. We’ve been worried about it since the COVID-19 pandemic started, with concern escalating in 2021 (and since then) as people became less concerned about respiratory viruses and were desperate to get out of the stay-at-home/wear-a-mask time. Now, though, we’re entering a new phase of this COVID-19 world, the post-emergency state of COVID-19, in which things have mostly gone back to normal, and we’re navigating sustained response to a pathogen that isn’t so novel. Our concern—and rightfully so—is if we’ll see a tripledemic. Three surges of respiratory pathogens during the winter, all converging on us at the same time, requiring public health and health care to manage response against COVID-19, influenza, and respiratory syncytial virus (RSV). A convergence of respiratory pathogens upon a burnt-out, fatigued, and increasingly stressed workforce during a time when we’re struggling to stop the cycle of panic and neglect and ensure sustainable resources and support for public health and pandemic preparedness.

Predictions in this case are difficult, though, because there are indications that we’ll see some surge, but hopefully, not as bad as predicted. So far, COVID-19 seems to be trending down. Hospitalizations are down in the United States, as well as emergency room visits (down 19.3%), according to data reported by the CDC. In week 38 of influenza tracking, the CDC hasn’t seen drastic increases. Looking back to week 40 of the 2022-2023 season, we already saw an uptick. That means that we’re not seeing the swift rise in numbers that would point to an early influenza season. Peaks are usually around weeks 48 and 50, so the next 2 months will be telling. Of the 42,904 specimens tested this week, 0.9% were positive, and a majority were influenza A. Looking a week back, that’s a bit of an increase, as test positivity was 0.8%. Looking back to the 2021-2022 influenza season for week 38, the CDC reported 50,292 specimens tested, with a positivity of 1.3% and much higher rates of influenza A.

Also in the Tripledemic Fall/Winter 2023-2024 Article Series

What about RSV and Influenza?

If we shift our attention to RSV, the latest data does show an uptick in RSV detection via PCR and antigen tests. These increases are concerning, and while not steep rises in cases, they may be the first indicators of a rough season coming our way. In addition to pathogen-specific surveillance, syndromic surveillance is helpful because we can see trends based on symptoms and preliminary diagnostics.

Utilizing the Influenza-like Illness Surveillance Network (ILINet), there has been an increase in outpatient respiratory illness visits, with 2.0% of reported patients experiencing symptoms like fever, sore throat, cough, etc. This season, we’re seeing an earlier rise in cases (compared to pre-COVID-19 seasons). Still, given that it is symptom-specific, it reflects symptoms that could indicate COVID-19, RSV, influenza, and other respiratory viruses. In short, we are seeing an uptick in respiratory viruses—specifically RSV and influenza, and a bit of a decline in cases of COVID-19. This can make for somewhat of a confusing time. If there’s one thing we’ve learned over the years, it’s that too often, respiratory virus season doesn’t play its hand too early. The 2017-2018 influenza season was particularly rough, and it wasn’t until weeks 42 and 43 that we started to see that rapid climb in cases, and week 49 was the indication of things to come. We will, of course, see an increase in cases—that is what history has taught us—but the severity of it and our capacity to respond in both the care of patients and prevention of additional cases depends on what we do now.

Avoiding--or At Least Curbing--the Tripledemic

First: vaccination. We are in one of the best positions in history to address these pathogens with vaccines. A new COVID-19 booster, an annually-updated influenza shot, and for the first time, new strategies to tackle RSV—an RSV vaccine approved for older adults, and an antibody treatment, Beyfortus, to protect infants, and a maternal vaccine to protect pregnant individuals and young infants. The issue now is to ensure people get the shots but also have easy access, which has been a challenge with reported hurdles due to insurance, supplies, and cost. Less than 20% of Americans got the previous COVID-19 booster, which doesn’t bode well for this season. Reports of a less-than-ideal booster rollout aren’t helping either.

“And the vaccine manufacturers say they've got sufficient doses available—the problem seems to be with distribution, [Jennifer Kates, senior vice president and director of the Global Health & HIV Policy Program at the Kaiser Family Foundation] explains [to National Public Radio]. Unlike years past when the federal government purchased the vaccines and made them free to consumers, this year, pharmacies had to buy the vaccines from suppliers. ‘This is the first time that the vaccines are being commercialized. They're being largely procured, supplied, [and] paid for in the private sector. So, it's sort of our health care system as we know it,’ Kates says. The problems include issues with insurance coverage. Since the government is no longer giving the shots away for free, most people need to use their health insurance to pay for them. (The federal government is only making the vaccines free for the uninsured, via a temporary program called Bridge Access.)”

What Else Can We do?

In addition to vaccines, we have the usual host of respiratory virus prevention strategies—staying home when sick, masking, hand hygiene, cleaning and disinfection, testing, and improving ventilation. For infection prevention programs, though, facing an impending tripledemic, no matter how severe it gets, requires us to prepare in a way that is a bit novel. Over the past few years, COVID-19 has translated to visitor restrictions, widespread masking, and prevention strategies covering the non-COVID-19 respiratory viruses we’re discussing. We are moving to a sustainable approach to COVID-19 prevention, including it as another respiratory pathogen we must prepare and respond to rather than the emergent and novel pathogen. This requires infection control and prevention programs to integrate COVID-19 metrics into respiratory virus season strategies, such as looking at these 3 viruses to establish metrics for actions, like visitor restrictions, universal or targeted masking (if not already in place), and enhanced measures to combat the growing cases we’re seeing in the community. Determining these now and, importantly, working with leadership and health care workers to ensure education and communication will be vital. Without federal- and state-based guidance, we’re in somewhat uncharted territory where variations between facilities will become increasingly apparent.

The truth is that right now, the data is showing indications of rising influenza and RSV cases, whereas winter COVID-19 surges tend to start in late October and early November. It will likely be a few weeks until we begin to see how steep the rise is and how severe a tripledemic is—if it happens. Regardless, we can determine just how bad it is. For IPC programs, taking the lessons of past winters and COVID-19 surges, we can build integrated plans that are agile and targeted. I’m hopeful that in 6 months, when we look back at this season, we’ll see a curbed respiratory virus season, made mild by our actions rather than severe by inaction and indifference.