Flu cases lower this year, state pushes vaccination

This graph shows the number of confirmed flu cases by week in South Dakota for each year. This year's numbers are lower than those for the 2019-2020 flu season.

The onset of winter typically signifies the beginning of influenza season, but with the addition of the COVID-19 virus this year, there are two respiratory viruses for which people need to prepare.

South Dakota Department of Health officials report a weekly summary of influenza cases and tests in the state starting in October and so far this year, there have been minimal flu cases — the weekly report for the week of Dec. 19 reported a 2.5% positivity rate for influenza tests. So far, there have been 12 cases to date in the state with five hospitalizations and two deaths. However, the low numbers do not mean people should get complacent.

“Typically, the peak for cases is in February, so we’re still not out of the woods yet for influenza season,” State Epidemiologist Dr. Joshua Clayton told the Capital Journal in a phone interview. “It’s difficult to predict what we will see with the co-circulation [of the flu and COVID].”

Clayton said flu cases increase faster in the time leading up to February, with the peak usually happening in the first or second week of that month and decreasing after that. Vaccination efforts typically begin in late September-October and slow down during the new year. This year, he said it is more important than usual to get vaccinated against the flu virus due to the COVID pandemic.

One reason is simply because both the flu virus and COVID are respiratory illnesses. COVID, however, has had a “much larger impact” on the health care system than other respiratory pathogens, Clayton said.

“Adding influenza on top of an already stressed health care system...we want to do all that we can to avoid people becoming sick with the flu and needing to require hospitalization, and hopefully decrease their risk of dying if they get vaccinated,” Clayton said.

With the flu circulating at the same time as COVID, there is also a risk of dual infection. There have been “a few” cases in the state of infections of both COVID and other respiratory pathogens including the flu. Clayton said that dual infections increase a person’s risk of severe illness because their body has to fight off two viruses at once, but it is difficult to predict what exactly would happen because of the many ways COVID can present itself.

Once a person gets the flu vaccine, it takes around two weeks for their body to develop the antibodies that will protect them from the virus. The flu vaccine lowers the risk of infection, and if one does become infected, the vaccine lowers the risk of hospitalization or death. Clayton said studies have shown flu vaccinations decrease overall hospitalizations by 37%, ICU hospitalization by 82%, and the overall risk of child illness by 50-65%.

“That’s pretty impactful when you consider people having to take time off of school or work for illness or individuals’ overall risk of illness,” Clayton said.

For those who have yet to receive a flu vaccine, there is still ample time to get one. In the past if the flu virus is still circulating, Clayton said he has made recommendations to continue vaccination efforts into March and April.

“It’s important to note while a lot of influenza vaccination campaigns trail off in the new year, there’s still an opportunity to be protected into January through March,” Clayton said. “While [flu cases] are low, we can’t predict what will occur in the new year.”

In comparison with last year’s flu season, there are fewer children under 5 years of age being vaccinated against the flu, but older teenagers and adults through age 64 have been taking the vaccine more so than last year, according to Clayton. There were 340,000 flu vaccine doses given out across all age groups last year, and this year’s vaccination numbers are trailing slightly behind the average for this time last year.

“Vaccinations are down 0.7% in total, so we’re in line with where we were last year. We would like to see that get higher, and we’re hoping people will get vaccinated into the new year,” Clayton said.

Health care professionals in the U.S. often look to Australia’s flu season to get an idea of what the flu season will look like in America. Clayton said this year Australia’s flu season was mild due to a higher vaccination rate and the initiation of mitigation strategies for COVID-19, such as mask wearing, social distancing, and avoiding large gatherings.

“All of this occurred in the context of doing more testing for influenza and having a less severe influenza year. Hopefully, we’ll see that milder flu season as well, but it’s hard to predict,” Clayton said.

Indeed, strategies to minimize COVID transmission are also effective against the flu virus. And similar to COVID-19, the flu affects older people (aged 60 and above) more severely, but unlike COVID, the flu also has more severe effects for children under 5 years old.

Flu vaccines are often free through your health care provider and can be found at pharmacies such as Walgreens or Walmart. For more information about the seasonal flu, visit the state department of health’s webpage at https://doh.sd.gov/diseases/infectious/flu/default.aspx.

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