SALT LAKE CITY – Flu rates in Utah and the United States continue to fall, a trend first seen a few months ago in the southern hemisphere of the world.
While flu infections are low, cases of COVID-19 across the country are on the rise, with at least nearly 1,000 reported daily 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 on the rise and flu cases so low?
The answer is really quite simple, according to Intermountain Healthcare infectious disease specialist Dr. Eddie Stenehjem.
“You had low flu in the US, you wore masks, you distanced yourself socially, and you had high (flu) vaccination rates,” Stenehjem said in a Q&A this week. “We really hope that this guy allows us to get out of the flu season without seeing any significant flu activity.”
As for why COVID-19 cases 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-naught) to indicate how easily a disease or virus spreads from person to person in a community.
Experts calculated the average R0 of COVID-19 to be 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 June report. For comparison, the average R0 for influenza in the Spanish flu pandemic of 1918 was about 1 to 2, according to an article published in BMC Medicine.
The number can vary greatly even between different areas and states and depending on the outbreak.
R0 is fluid and does not present a complete picture of how contagious a disease is, but it does provide a starting point, despite its many limitations. However, one thing remains clear: COVID-19 is more contagious than the flu.
He was already in the community
COVID-19 has been spreading in communities since the spring, which means that when winter came, the virus was already spreading, Stenehjem explained.
Influenza, on the other hand, is usually brought to a community in the southern hemisphere. But with low flu shots there, he never really got here, he said.
This time last year, Intermountain saw about 80-100 cases of flu every day. This year, the health care system has reported only a handful of cases in the last few months.
Intermountain hospitals are actively looking for flu cases with extensive testing, Stenehjem said.
“It’s not out of appearance, it’s just that we don’t see the flu,” he said.
The Utah Department of Health is also looking for flu cases in the state, and since the week of December 13-19, cases have remained low. By this flu season, which began in early October, a total of seven people had 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 prominent 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 spread across the state to those eligible to receive it in the first phase – but the population is far from the herd’s immunity.
Influenza vaccines, on the other hand, have largely increased throughout the country.
The US Centers for Disease Control and Prevention reported that 192.3 million doses of influenza vaccine have been distributed since last week and it is possible that up to 198 million doses will be distributed in the 2020-21 season. These figures have increased significantly compared to 2019, where 174 million were distributed in the 2019-2020 flu season.
For Utah, more age groups appeared to have a higher number of flu vaccines reported this year than 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 fewer flu vaccinations than in 2019, such as the 6 to 4 year age group.
In general, national flu vaccines appear to be on the rise compared to last year, which Stenehjem said contributes to the low number of flu.
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Lauren Bennett