Hawaii added a one-time bump of 1,600 cases to its total coronavirus count on Wednesday as officials began incorporating so-called probable infections that were never confirmed.

The move, health officials said, was aimed at providing a more accurate portrayal of COVID-19’s prevalence in the state and adjusting for an anticipated increase in the use of rapid antigen tests that are considered less accurate than the state’s preferred molecular-based tests.

People with a known exposure, symptoms, or who had a positive rapid test are considered by officials to be probable cases. Only those who test positive with a molecular-based PCR test are logged as a confirmed case.

Historically, the islands have seen about 10 to 20 probable cases per week, according to state health officials. Going forward, those probable cases will be included in the Hawaii Department of Health’s daily data reports.

The change is not likely to affect Hawaii’s tier systems that dictate which activities are permitted based on weekly average case counts, acting state Epidemiologist Dr. Sarah Kemble said in a Facebook video posted by the Department of Health.

“I don’t think it will have a very big impact on what we see in seven-day averages, which is what we use in the tier system,” she said. “Many of the probable cases go on to be confirmed, so they don’t stay as a probable case.”

The tier system is determined by the county governments. Honolulu Mayor Rick Blangiardi’s office did not provide comment on the issue.

The decision comes amid shifting dynamics of the pandemic as people increasingly get vaccinated against COVID-19 and the Centers for Disease Control and Prevention relax federal guidance on safety protocols and travel restrictions.  

Thomas Lee, co-chair of the Hawaii Pandemic Applied Modeling group and an assistant professor of epidemiology at the University of Hawaii, applauded the move.

“We always knew there was underreporting, especially in the beginning because of a lack of access to tests due to the supply chain,” he said. “This is important to better capture the prevalence of disease that is circulating in the state, even with the vaccination that’s going on.”

Other states already have adopted the practice. Missouri began reporting probable cases identified through antigen testing in March. Texas started to report probable cases in December, resulting in a one-day increase of about 44,000 cases, according to the New York Times.

Georgia and New Jersey have included probable deaths as part of their data reporting since last fall.

Hawaii reported 73 new COVID-19 cases statewide Wednesday, 15 of which were “probable,” with an average of 1.6% of tests conducted within the last week returning positive. 

But it also added all probable cases since the pandemic began, raising the state’s cumulative total to 33,585. 

Meanwhile, nearly 1.4 million vaccine doses have been administered in the Aloha State. Approximately 46% of all Hawaii residents are fully vaccinated while 55% have received at least one dose.

One reason why DOH decided to display probable cases more prominently on its website is because the use of rapid testing is expected to increase, Kemble said.

“We’re seeing a lot of change and development in testing technologies, and probable cases as defined by antigen tests is something that’s becoming a more common practice,” she said. “It’s important for us to capture what’s actually going on in the pandemic and that picture includes these probable cases.”

The state acquired a stockpile of rapid tests last year that it has used to gather quick results at nursing homes, care homes, prisons, housing complexes and hospital facilities.  

“When you’re trying to quickly capture whether or not a surge is occurring, a rapid test can be very useful as a baseline,” Lee said.

The Health Department continues to use rapid COVID-19 tests at various pop-up public events held for free at locations such as the University of Hawaii or Windward Mall.

Some counties, including the Big Island and Maui, have utilized rapid tests at airports.

Maui has conducted so many rapid tests that its probable case count is currently the highest of all counties, Kemble said.

Lee also believes the latest CDC guidance, which recently took a more lax approach to baseline testing requirements for fully vaccinated people, may have played a role in the decision to include probable cases in the state’s count.

The public health agency said last week that fully vaccinated people no longer need to get tested for COVID-19 before domestic travel and don’t need to bother getting a test if they don’t have symptoms even with a known exposure, with some exceptions.

Hawaii’s policy is stricter than this latest national guidance. It requires proof of a negative molecular test conducted by an approved laboratory from all trans-Pacific arrivals who wish to skip an otherwise mandatory 10-day quarantine. Rapid tests aren’t accepted, prompting some confusion and contributing to long lines at the airport.  

However, rapid antigen tests are only growing in popularity, especially if they are produced en masse and offered at cheaper prices.

“With at home test kits people are going to want to test at home versus something getting stuck up their nose for a PCR (molecular) test,” Lee said. “There is a big market for antigen tests and we’re moving toward home tests.”