Hawaii’s Influenza Surveillance Program

The seasonal flu is a common illness occurring every year primarily between the months of November and May (winter months) in the northern hemisphere. In Hawaii, because of our high volume tourism and tropical climates, we experience flu year round. The Hawaii Department of Health (HDOH) Influenza Surveillance Program conducts routine year round surveillance for influenza.

Frequently Asked Questions

What is influenza surveillance?

Many people who get sick with the flu do not visit a doctor or report the illness to HDOH. So the Hawaii Department of Health uses various indicators to track influenza in the state. The combined output of all these indicators helps us determine what strains of virus are circulating in the general population, how sick people are getting from the flu, what percentage of people maybe getting sick with the flu, and also investigate flu outbreaks in long term care facilities and schools across the state.

Why is influenza surveillance important to Hawaii?

Because of our isolated location and huge tourist volume, Hawaii’s influenza trends during any given year may be very different from that on the United States mainland or other parts of the world. The last several flu seasons have shown us that our seasonal peaks can occur during a different month than on the mainland, and the circulating flu viruses can also be very different. Sometimes flu trends on one island can be distinctly different from trends on another island. These factors make influenza surveillance in Hawaii crucial. Through surveillance, we understand how the flu impacts our state, and helps the Hawaii Department of Health focus its efforts on improving health among the people of Hawaii.

What is the Hawaii Influenza Surveillance Program?

Hawaii’s influenza surveillance program is made possible by the cooperative agreement of several organizations within and outside the Department of Health. Your physicians, hospitals, commercial laboratories, and the Department of Health’s Disease Outbreak Control and State Laboratories Divisions collaborate to make influenza surveillance in Hawaii possible.

What information does the Hawaii Department of Health (HDOH) use to track flu in Hawaii?

HDOH monitors flu in Hawaii through several resources:

  • Physicians and laboratories report severe cases of influenza, so that we can track and investigate those flu infections that result in hospitalizations.
  • Some hospitals that conduct their own influenza testing report all positive cases to HDOH.
  • Hawaii’s sentinel providers report the number of patients they see in their own medical practices for flu-like-illnesses.
  • The Hawaii Department of Health’s State Laboratories Division receives and tests thousands of specimens through commercial laboratories from individuals who visited their physicians for flu like illnesses to determine whether they were infected with the flu, and if so, what type.
  • The State Laboratories Division also sends several flu isolates to the Centers for Disease Control and Prevention (CDC). Using this system, the HDOH informs CDC of the types of flu viruses circulating in Hawaii.  In exchange, the CDC conducts detailed analysis on the specimens and sends us further information about the influenza trends in Hawaii.
  • Schools and Long Term Care Facilities report suspected outbreaks of influenza to HDOH. HDOH routinely investigates such reports.
  • Hawaii receives specimen submissions from the Hawaii Quarantine Station at the Honolulu International Airport through our Airport Surveillance Program. Through this system, we identify travelers entering our state with influenza like illness, and monitor flu strains that enter our islands through airways.
  • HDOH’s Vital Statistics Program provides year-round information on the number of pneumonia and influenza related deaths in the city of Honolulu each week.
Does Hawaii’s Department of Health (HDOH) know about every influenza case in the State of Hawaii?

No. HDOH neither attempts to keep track of all influenza cases in Hawaii, nor is such a task truly possible. Flu is a common viral respiratory illness. Many people with the flu do not go to the doctor when they become ill; many doctors do not perform influenza testing. Some doctors perform testing in house but do not report these results to HDOH.

The point of influenza surveillance is to understand flu trends and estimate numbers rather than get actual counts. Our goal is not simply to get an accurate count of flu cases in Hawaii. We would rather spend our time using the information we obtain to help protect our public from the flu.

What does the Hawaii Department of Health (HDOH) do with all the specimens it receives?

HDOH’s State Laboratories Division routinely tests thousands of specimens each year for influenza. Testing is conducted using state of the art Real Time Polymerase Chain Reaction (RT-PCR) and viral culture techniques. RT-PCR is a fast and reliable technique used to detect the presence and type of influenza in a specimen. Viral culture is a slower technique, taking several weeks for viral isolation; both methods are considered the “gold standard” within influenza testing. Specimens are analyzed using either or both techniques as necessary, and sometimes forwarded to the CDC for further analysis.

How is the data received by the Hawaii Department of Health (HDOH) interpreted?

The results of our State Laboratories Division influenza testing are used to understand influenza trends in the State of Hawaii. Because of such testing, we know what types of influenza and other respiratory viruses circulate in our populations including their relative proportions, whether the current flu vaccine protects us against the circulating influenza strains, when we observe the most influenza during the flu season, and the distribution of influenza across the islands.  Data obtained by the Hawaii Department of Health from the State Laboratories Division, physicians, laboratories, hospitals, commercial laboratories, sentinel providers, CDC, schools, long term care facilities, Hawaii’s Airport Quarantine Station, and the Vital Statistics Program is primarily used to protect the public, and keep Hawaii’s residents informed about how to avoid getting the flu, what to do when you get sick, and how Hawaii’s flu trends may affect you.  As part of HDOH’s efforts to keep the public informed, influenza data from various sources is compiled to provide a thorough and robust understanding of the influenza trends in our state. HDOH compiles weekly and annual reports to summarize all the information it receives. View HDOH’s latest weekly influenza report.

How can I learn about seasonal influenza trends in Hawaii? How do Hawaii’s influenza trends compare with those on the US mainland?

Each week, the Hawaii Department of Health (HDOH) publishes a “real time” up-to-date influenza report that informs you of various influenza trends in the state. The report provides national data during the flu season so you can compare Hawaii’s trends with those seen on the US mainland. At the end of each flu season, HDOH publishes an annual seasonal summary that describes influenza trends over the course of the flu season. View HDOH’s latest weekly influenza report.

How can I learn about seasonal influenza trends in the United States?

Each week, the Centers for Disease Control and Prevention (CDC) publish an influenza report that informs you of influenza trends across the United States. In addition, the CDC also prepares and publishes an annual seasonal summary at the end of each flu season. View the CDC’s influenza reports.

How can clinical providers help contribute to Hawaii’s Influenza Surveillance Program?

Clinical providers, including nurses, doctors, and nurse practitioners, can volunteer to become sentinel providers for the state of Hawaii.  Sentinel providers must be practicing and be able to see patients for influenza-like illness. As a sentinel provider, you will agree to provide counts on total patients seen each week, total patients seen each week for influenza-like illness, and be able to group patients by age. By becoming a sentinel provider, you can contribute invaluable information that has the ability to show when influenza season starts, when it peaks, and when it ends in Hawaii.