Virus triple threat
Worst of ‘tripledemic’ may be over.
Early in the COVID pandemic, surges of other seasonal respiratory viruses like influenza and respiratory syncytial virus (RSV) were far below normal levels, likely because of masking and other precautions that were in place to try and stifle the spread of SARS-CoV-2.
But in the third year of the pandemic, as the public has largely abandoned masking and other measures, public health experts warned of the threat of a “tripledemic” of COVID, flu, and RSV infections.
It’s still too early in the season to get a final tally on the toll of each of these viruses, but so far each has made a strong showing.
RSV cases got an early start, ticking up as early as May and peaking around fall, according to the Centers for Disease Control and Prevention (CDC).1
COVID-19 infections were declining through most of 2022, but new the highly Omicron transmissible variant changed that. The version of Omicron that was circulating the United States in late 2022 and into early 2023—XBB.1.5—has proven to be highly contagious, but not necessarily leading to as many hospitalizations or severe illness as previous variants.2
Influenza cases were still being reported at high numbers as of mid-January, but the CDC revealed that infections appeared to be trending down. Annually, there are between 9 million and 41 million cases of influenza reported in each flu season, according to the CDC.3 This year’s total so far is at about 24 million, the CDC reports.4 While this total places the year’s cumulative flu burden at an average level, it’s not uncommon for flu cases to continue into early spring.
The good news is that each of these viruses have seemingly taken turns reaching a peak, despite warnings that the U.S. was headed for a triple pandemic of flu, COVID, and RSV this winter. Although it may not seem like it for families who have battled one illness after another, the worst of the predicted “tripledemic” seems to have missed its predicted target.
Adam J. Ratner, MD, of Hassenfeld Children’s Hospital at NYU Langone and a member of the American Academy of Pediatrics’ committee on infectious diseases, says it seems like these viruses had the greatest impact on higher risk groups, including children with other comorbidities or those did not receive the available vaccinations.
“I think it’s been a really bad respiratory viral season all over the country, and different areas have seen different things,” Ratner says.
RSV and flu made up the bulk of infections—at least those that he saw requiring hospital admission—early in the season, Ratner says. Hospitalizations are on the decline, now, but there are still plenty of kids becoming sick enough with any of these viruses to need a hospital bed, he adds. New COVID variants caused a spike in cases over the holidays, he says, but for a variety of reasons, severe illness from COVID appears to be limited to high-risk individuals for the most part.
“Most people in the U.S. Have some immunologic experience, meaning they’ve had COVID, been vaccinated one or more times, or both,” Ratner says, adding that there are estimates that somewhere around 75% of children in the U.S. have now been infected with COVID at some point during the pandemic whether they knew it or not.
There have been some co-infections with more than one of these viruses at a time, too, Ratner says, but there isn’t really any data that shows co-infection is leading to more severe illness. On the other hand, Ratner says complications like bacterial pneumonia can happen after an initial infection with COVID, flu, or RSV.
Vaccinations, when available, remain the best defense, Ratner adds. COVID and flu vaccines are available, but effective RSV immunizations are still in trial phases. One maternal vaccine from Pfizer has shown promise, he adds, and there is good data on the efficacy of long-acting monoclonal antibodies.
Currently, oseltamivir remains the treatment of choice for influenza, Ratner says, and remdesivir can be used in children who need hospitalization from COVID-19 or require oxygen therapy. Nirmatrelvir/ritonavir, another COVID treatment option, is only approved for children aged 12 and up, Ratner says.
RSV is perhaps the most difficult to manage beyond supportive care. Monoclonal antibodies are more of a preventive tool than a treatment option, he says. This treatment is used in premature infants and young children with congenital lung diseases, and its given monthly for their first RSV season, Ratner says.
While the winter respiratory virus season is far from over, Ratner says hospitalizations do appear to be on the downswing, and the number of children requiring intensive treatments remains relatively low.
“Fortunately for kids, getting hospitalized and needing that level of support is much rarer for kids than adults,” Ratner says.
Reference
1. RSV Numerator Data for the U.S. Centers for Disease Control and Prevention. Accessed January 15, 2023. https://www.cdc.gov/surveillance/nrevss/images/trend_images/RSV14Num_Nat.htm.
2. COVID-19: COVID data tracker weekly review. Centers for Disease Control and Prevention. Accessed January 16, 2023. https://www.cdc.gov/coronavirus/2019-ncov/covid-data/covidview/index.html.
3. Disease burden of flu. Centers for Disease Control and Prevention. Accessed January 17, 2023. https://www.cdc.gov/flu/about/burden/index.html.
4. Weekly U.S. influenza surveillance report. Centers for Disease Control and Prevention. Accessed January 17, 2023. https://www.cdc.gov/flu/weekly/index.htm.
