PORTLAND, Ore. (KOIN) – Oregon Health & Science University says the flu, not COVID-19, could cause more people to be hospitalized in the fall and winter. This comes after the latest statewide COVID-19 forecast was released Friday. 

The OHSU COVID forecast is released every two weeks. 

The report released Friday took a close look at what to expect for the upcoming influenza season and how the flu’s impact will compare to COVID-19’s. Since the flu was all but absent for the past two and a half years while the public wore masks and limited their gatherings, health officials say it’s extremely important people get their flu shots this year. 

“The flu is probably going to be at least as important this year as COVID,” said Dr. Peter Graven, director of the OHSU Office of Advanced Analytics. 

Doctors have monitored influenza rates through the fall and winter in the southern hemisphere to predict how it will affect the U.S. as it heads into its own fall and winter.  

Cases of the flu were higher than usual in Australia, but hospitalizations were close to those in 2019 and less than those in 2017. 

In South America, there were no significant spikes in flu cases. 

Because public health measures minimized the circulation of the flu during the past two years, Dr. Dawn Nolt said the immune system is out of practice when it comes to fighting off the influenza virus. That could result in a potentially vigorous flu season when the virus begins circulating in the fall. 

“In normal years, lots of people are exposed to the flu, which provides a natural boost to their immune response,” she said. “We haven’t seen much flu at all in the past three years. That makes it really important to get yourself vaccinated against flu this season.” 

In its bi-weekly forecast, OHSU predicted what four different flu scenarios would look like. 

Scenario A involved high flu vaccination – 10% higher than in 2020-2021 for each age group – and an optimistic expectation of prior flu immunity. 

Scenario B represents high flu vaccination protection, but a pessimistic expectation for prior flu immunity, meaning people would have 50% lower immunity than a typical, pre-COVID flu season. 

Scenario C has low vaccination protection – where the vaccination coverage is 10% lower than 2020-2021 – and optimistic prior flu immunity. 

Scenario D has low vaccination protection and pessimistic prior flu immunity. 

Among these four scenarios, OHSU predicts Scenario D would result in the most weekly hospital admissions for influenza. If Scenario D plays out, OHSU predicts more than 1,200 would be admitted to the hospital in a week in early January, before hospitalizations began to decrease. 

The best scenario is Scenario A, where researchers predict hospitalizations for the flu would peak in late January or early February with about 200 people admitted in a week. 

The latest COVID-19 forecast shows a steady decline in the number of hospitalized patients with COVID-19. OHSU predicts this number will climb slightly in November as immunity wanes and more people start gathering indoors. 

However, even with the number of COVID-19 cases expected to climb, OHSU predicts that by December, the flu will result in three times more hospital admissions than COVID-19. This occurs when scientists average the flu rate for Scenarios A and C.  

OHSU is asking people to get the flu vaccine and the latest COVID-19 booster, which targets the BA.4 and BA.5 variants, as soon as the shots are available. The Oregon Health Authority has an online map showing pharmacies offering COVID-19 vaccines and boosters.