CDC warns of ‘tripledemic’ winter in which Covid, RSV and flu cases collide

Federal health authorities are urging Americans to stay up to date on all vaccines to avoid slowing down the healthcare system during cold and flu season.

The Centers for Disease Control and Prevention (CDC) released a new statement on the potential for a “tripledemic”, in which cases of Covid-19, influenza, and respiratory syncytial virus (RSV) all circulate at the same time and are massively disruptive to urgent care centres and hospitals.

If all three viruses peak at the same time, they have the capacity to overwhelm healthcare centres causing delays to routine appointments, such as cancer screenings.

Before Covid-19 emerged, RSV and flu caused millions of illnesses during the fall and winter months. Flu causes an estimated 9 million to 41 million illnesses each year, while RSV causes more than 2 million illnesses in children under five alone. Among people 65 and older, RSV causes up to 10,000 deaths annually.

SARS-CoV-2, the virus that causes illness with Covid, added an extra burden to an already fragile system, experts say. “As with last year, the total number of hospitalisations this year is expected to be higher than what we as a nation experienced prior to the COVID-19 pandemic,” the new statement said. According to the most recent data from the CDC, from 3 September to 9 September, hospitalisations from Covid rose 7.7 per cent compared to the previous week. Deaths from the virus rose 4.5 per cent during the same time period.

The outlook released in the new CDC statement shows projections for what could happen if all three viruses peak at the same time, and experts say that scenario is cause for concern.

“When a disease is endemic, it means that the levels are mostly predictable. So it’s nice to see the CDC putting out their predictions this fall,” Dr Ellie Murray, an assistant professor of epidemiology at Boston University School of Public Health, tweeted in response to the outlook. “[On the other hand], it’s not so nice that their best case scenario is almost twice as many respiratory hospitalizations as pre-COVID.”

During last year’s tripledemic, the peaks of the three viruses overlapped, causing chaos in emergency care centres. RSV, in particular, took a massive toll on children – at one point, every single paediatric hospital bed in the state of Rhode Island was full, according to reporting from NBC News.

This is the first year that vaccines are available for each virus; to prevent healthcare shutdowns, the CDC is recommending that all those who are eligible stay up to date on all their shots.

Adults 60 and older are eligible for the RSV vaccine, while everyone six months and older can get the updated Covid-19 and flu vaccines.

“Vaccination against these respiratory viruses is important for everyone and especially for those who are at higher risk of developing serious complications, including older Americans and those with medical complications,” the new statement said.

Infants and older adults are at high risk for severe disease from both RSV and influenza, while Covid is more dangerous for people over 65; more than 81 per cent of deaths from Covid occur in this age group. People with certain medical conditions – such as asthma – or who take immunocompromising medications are also at an increased risk.

If viral infections do cause a tripledemic, people in the US may need to start wearing masks and social distancing. That these behaviours weren’t implemented during last year’s cold and flu season was part of the problem, experts say.

Another factor that crippled the healthcare system last year was Americans’ hesitancy to get vaccinated: Only a quarter of US adults got the bivalent booster that was made available in September 2022, according to data from KFF, a health policy research group.

While people in certain age brackets and with certain health conditions are more likely to need hospitalisation from RSV, Covid, and flu, anyone can get very sick from these viruses. Therefore, staying up to date on all vaccines does more than protect healthcare infrastructure, the CDC says.

“Vaccines are the safest way to build immunity from a virus,” the agency said in a statement on tripledemic viruses. “The immunity you gain from vaccination can reduce your risk of infection and becoming very sick if you do get infected.”