Flu is a contagious respiratory illness caused by a virus that infects the nose, throat, and sometimes the lungs. It can cause mild to severe illness, and at times can lead to death. Those who are at high risk of complications due to flu include children younger than 5 years old, people older than age 65, pregnant people, and people who have certain pre-existing conditions such as asthma, diabetes, chronic kidney disease, heart disease, or have had a stroke. Luckily, there are steps you and your family can take to fight flu and stay healthy this flu season. Find more information on the CDC site for Influenza (Flu).
The best way to prevent flu is by getting a flu vaccine each year. You can find flu vaccine providers here.
Take preventive actions to stop the spread of germs. Wash your hands, cover your cough, and stay home from work or school when you are sick.
Take influenza antiviral drugs if your doctor prescribes them.
The gauges below indicate the severity of the current flu season based on historical data from previous seasons. A green gauge indicates low severity, yellow indicates moderate severity, red indicates high severity, and purple indicates very high severity.
For the 2018-2019 flu season, DHHS (previously UDOH) adopted a new methodology to determine flu season severity called the Moving Epidemic Method. Based on data from past flu seasons, DHHS uses key flu indicator data to develop intensity thresholds (ITs) to classify the severity of flu seasons from low to very high. The indicators used in Utah include only:
Indicators below the IT50 threshold are shown in green in the gauges and plots below, and are considered low severity. Indicators between IT50 and IT90 (yellow) are considered moderate severity, indicators between IT90 and IT98 (red) are considered high severity, and indicators above IT98 are considered very high severity (purple). This methodology was published by CDC researchers in the American Journal of Epidemiology in October 2017.
Influenza-associated hospitalization (IAH) is a reportable condition in Utah. People meet the case definition for flu hospitalization if they are hospitalized for any length of time and have a positive influenza laboratory test within a specific time frame. More information about this definition can be found on the Seasonal Influenza Disease Plan. Public health in Utah gathers a variety of data on influenza hospitalizations, including clinical features, course of illness, risk and protective factors, and influenza type and subtype. Data from influenza hospitalizations allow public health officials in Utah to better understand the groups of people most severely affected by influenza and help guide prevention messages and interventions. Data collection for the 2024-2025 influenza season began on September 29, 2024.
The U.S. Outpatient Influenza-like Illness Surveillance Network
(ILINet) is a national system that conducts surveillance for ILI in
outpatient healthcare facilities, including emergency departments. For
this system, ILI is defined as fever (temperature of 100ºF or greater)
and a cough and/or sore throat. These data provide an indication of ILI
circulating in the community.
Note: As of 04/14/24, some
facilities are in the process of changing how they report ILI data,
which may result in missing ILI data for subsequent weeks. We are
working with these facilities to re-establish reporting as soon as
possible.
The ILI activity in local health department jurisdictions is calculated differently than the state severity above. Local ILI levels are based on the comparison between current ILI reports and jurisdictional baselines. These methods are similar to the methods used by the Centers for Disease Control and Prevention (CDC) to measure state-specific ILI activity. More information on the methods used to calculate jurisdictional ILI activity can be found here.
The Utah National Electronic Disease Surveillance System (UT-NEDSS) maintains influenza testing results from hospital laboratories and the Utah Public Health Laboratory (UPHL). UPHL tests influenza specimens to determine influenza type and subtype. A portion of specimens are also sent to the Centers for Disease Control and Prevention for additional typing and characterization. The results below include positive influenza tests reported to the Utah Department of Health and Human Services from both hospitals and outpatient facilities.
| Weekly count | Weekly percentage | Count | Percentage | |
|---|---|---|---|---|
| Influenza A | 113 | 93.4% | 390 | 86.3% |
| Influenza A seasonal H1 | 3 | 2.6% | 22 | 5.6% |
| Influenza A seasonal H3 | 3 | 2.6% | 16 | 4.1% |
| Influenza A, unsubtyped | 107 | 94.7% | 352 | 90.3% |
| Influenza B | 8 | 6.6% | 58 | 12.8% |
Influenza A viruses can be typed into different strains. The most common subtypes of influenza A viruses found in people are influenza A (H1N1) and influenza A (H3N2) viruses. In the spring of 2009, a new influenza A (H1N1) virus emerged that caused severe illness in humans. This new virus was very different from the human influenza A (H1N1) viruses circulating at that time and caused the first influenza pandemic in more than 40 years. That virus (often called “2009 H1N1”) has now replaced the H1N1 virus that was previously circulating in humans. Some influenza tests are unable to differentiate between influenza A strains, so many positive influenza A results reported to DHHS are unsubtyped.