SALT LAKE CITY – Flu rates in Utah and the United States remain low, a trend seen for months in the southern hemisphere of the world.
Although influenza infections are low, cases of COVID-19 across the country are still on the rise, with at least nearly 1,000 reported every day in Utah 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 cases of coronavirus rising and flu cases so low?
The answer is really quite simple, according to Intermountain Healthcare infectious disease specialist, Dr. Eddie Stenehjem.
“You had a low flu coming to the United States, all wearing masks, social distance and high vaccination rates (against flu),” said Stenehjem in a question and answer session this week. “We really hope it will allow us to get through the flu season without seeing any significant flu activity.”
And why haven’t the COVID-19 cases been closed? Here’s 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 spreads from person to person in a community.
Experts calculated that the average CO0-19 R0 is between 2 and 4, meaning that an infected person can transmit the disease to two or more people, the World Health Organization said in a June report. For comparison, the average R0 for influenza in the Spanish flu pandemic of 1918 was approximately between 1 and 2, according to an article published in BMC Medicine.
The number can vary widely, even across different areas and states and depending on the outbreak.
R0 is fluid and does not show a complete 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.
I was already in the community
COVID-19 has been spreading in communities since spring, which means that when the winter came, the virus was already spread, explained Stenehjem.
The flu, on the other hand, is usually brought to a community in the southern hemisphere. But with a few flu cases there, he never really made it this far, he said.
At this time, last year, Intermountain saw about 80-100 cases of flu daily. This year, the healthcare system has registered only a handful of cases in the past few months.
Intermountain hospitals are actively looking for flu cases with extensive testing, said Stenehjem.
“It is not for lack of looking, it is just that we are not seeing the flu,” he said.
The Utah Department of Health tracks flu cases in the state as well, and in the week of December 13-19, cases remained low. So far in this flu season, which started in early October, a total of seven people have been hospitalized with the flu.
“We are not seeing many other viruses circulating in Utah,” said Stenehjem. “COVID-19 is by far the most prominent respiratory viral infection that we are seeing here in Utah.”
We don’t have a population vaccinated with COVID
In the past few weeks, COVID-19 vaccines have been distributed across the state to those who can receive it in the first phase – but the population is far from herd immunity.
Flu vaccination, on the other hand, has increased widely across the country.
The U.S. Centers for Disease Control and Prevention reported that 192.3 million doses of flu vaccine were distributed last week and it is possible that up to 198 million doses could be distributed in the 2020-21 season. These numbers increased significantly compared to 2019, where 174 million were distributed over the 2019-2020 flu season.
For Utah, several age groups appear to have a higher number of flu vaccinations reported 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 pattern and reported lower flu vaccination numbers than in 2019, such as the 6-month to 4-year age group.
Overall, flu vaccinations across the country appear to have increased over the past year, which Stenehjem said contributed to low flu numbers.
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Lauren Bennett