Why are flu rates so low as COVID-19 continues to rise? Utah doctor explains

SALT LAKE CITY – Flu rates in Utah and the United States remain low, a trend first seen months ago in the southern hemisphere of the world.

Although influenza infections are low, cases of COVID-19 across the country continue to increase with at least nearly 1,000 reported in Utah every day since the end of September.

For some, the numbers don’t make sense – if public health measures protect people from the flu and COVID-19, then why are new coronavirus cases on the rise and influenza cases so low?

The answer is very simple, according to Dr. Eddie Stenehjem, infectious disease specialist at Intermountain Healthcare.

“You had low flu when you got to the US, you have everyone wearing masks, you have social distancing and you have had high rates of (flu) vaccinations,” Stenehjem said during ‘a question period this week. “We really hope this will get us through the influenza season without seeing any significant influenza activity.

As to why the cases of COVID-19 have not decreased? Here is what Stenehjem said.

The new coronavirus is more contagious than the flu.

Scientists use a mathematical term called R0 (pronounced R-nothing) to indicate how easily a disease or virus is spread from person to person in a community.

Experts have calculated that the average R0 of COVID-19 is between 2 and 4, which means that an infected person can spread the disease to two or more people, the World Health Organization said in a report by June. For comparison, the average R0 for influenza during the 1918 Spanish influenza pandemic was around 1 to 2, according to an article published in BMC Medicine.

The number can vary widely, even between different areas and states and depending on the outbreak.

R0 is fluid and does not give the full picture of how contagious a disease is, but it does provide a starting point, despite its many limitations. One thing, however, remains clear: COVID-19 is more contagious than the flu.

It was already in the community

COVID-19 has been spreading in communities since spring, which means when winter came, the virus was already widespread, Stenehjem explained.

The flu, on the other hand, is usually introduced to a community in the southern hemisphere. But, with low cases of the flu there, it never really worked out here, he said.

This time last year, Intermountain saw around 80 to 100 cases of the flu per day. This year, the health care system has only reported a handful of cases in recent months.

Intermountain hospitals are actively looking for influenza cases with extensive testing, Stenehjem said.

“It’s not for lack of glance, it’s just that we don’t see the flu,” he said.

The Utah Department of Health is also tracking flu cases in the state and as of the week of December 13-19, cases remained low. So far this flu season, which started in early October, a total of seven people have been hospitalized with the flu.

“We really don’t see a lot of other viruses circulating in Utah,” Stenehjem said. “COVID-19 is by far the most significant respiratory viral infection we see here in Utah.”

We do not have a population vaccinated against COVID

In recent weeks, COVID-19 vaccines have been rolled out statewide for those eligible to receive it in the first phase – but the population is far from immune to the herds.

Flu vaccinations, on the other hand, have increased dramatically across the country.

The United States Centers for Disease Control and Prevention reported that 192.3 million doses of influenza vaccine were distributed last week and that it is possible that up to 198 million doses could be distributed during the season 2020-2021. These figures are a significant increase compared to 2019, when 174 million were spread over the 2019-2020 influenza season.

For Utah, several age groups appear to have a higher number of reported flu shots this year compared to last year, according to the Utah Department of Health.

However, it is important to note that some age groups did not follow the model and reported lower flu shot numbers than in 2019, such as the 6 months to 4 years age group.

Overall, flu shots across the country appear to be up from last year, which Stenehjem says is contributing to the low number of flu.

Related stories