Early COVID Surveillance Testing Shows Minimal Virus Penetration of Hawai‘i’

Hawai‘i’s pre-travel test is doing what it’s supposed to, at least so far.

Dr. F. DeWolfe Miller, epidemiologist and Professor Emeritus at the University of Hawai‘i John A. Burns School of Medicine, manages the state’s surveillance testing program, which administers and records secondary coronavirus tests of roughly 10% of passengers four days after they arrive from the mainland.

Just shy of one month into the pre-travel testing program, which mandates all travelers to Hawai‘i receive a COVID-19 test from a trusted partner before departure, Miller said the incidence of positive coronavirus cases slipping through the cracks to move freely about the state is between 1–1.2 per 1,000 individuals, or 0.001%.

“Right now, it looks good, and it looks like it’s working,” Miller said. “If we do (continue enforcing) the masking and the follow-up, I don’t see why we shouldn’t go ahead and continue with the program of travel we have right now.”

Health experts credit the quality of the PCR tests travelers are required to take with the early success of the pre-travel program.

“It’s a magical piece of technology,” Miller said. “You get false positives, it’s so sensitive.”

On Wednesday, just more than 7,700 arrivals were documented at state airports, which would equate to a projection of roughly nine COVID-positive individuals slipping through Hawai‘i’s viral net. Based on current average rates of travel, fewer than 10 infected individuals are making their way to the islands on a daily basis.

Miller said that number is insignificant in its projected impact on public health, assuming everyone follows established protocols of wearing facemasks, practicing social distancing, and limiting social gatherings. Some will fall ill and report for medical care, which will land them in quarantine. Masks, Miller said, should take care of the rest.

“A (statewide masking mandate) should have been done eight to nine months ago,” he continued. “Masking really works. We have both the science to show that masking works and the mechanism of action — how the mask actually stops the virus.”

“Viruses are really small. Elephants are really big. The thing they have in common is neither one of them will go throw a mask,” Miller explained. “The virus, when comes out in your breath, it’s wet because it’s mixed with mucus. As soon as it gets near any fibers on the mask, it’s going to adhere to the inside. As soon as the virus is dry, the virus is dead. The little tiny droplets in aerosols evaporate quickly. The outside of the mask will catch (the droplets from) someone breathing on you.”

Visitors from Japan will soon be returning to Hawai‘i with the potential for quarantine exemption by way of pre-travel testing. Miller said those travelers will pose even less risk than mainlanders because that country’s citizens emphasize and follow through with the use of facemasks far better than do Americans.

According to multiple surveys in recent months, including a HealthDay/Harris poll published at the end of August, most Americans do mask up, with nine in 10 saying they wear masks sometimes, often, or always when going out in public. However, only six in 10 said they wore facemasks religiously every time they left their homes.

Miller said masks will continue to be paramount to public health and cautioned against overconfidence with the reporting of surveillance testing numbers.

“It looks good right now,” he said, “but it could change and go south on us.”

While promising, the data remains somewhat minimal because it’s only been a few weeks since travelers began returning to Hawaiian shores.

Much of the data Miller’s team was utilizing came from the Big Island, where secondary COVID tests upon arrival at the airport were a requirement. That changed exactly one week ago, when Hawai‘i County Mayor Harry Kim was forced by constraints of financial, spatial, and personnel natures to roll back the program and test only 20% of those arriving.

Data is now funneling to Miller and his team from all islands, just not as much of it due to the Big Island downturn.

“You need good databases and a good watchdog system so you can know when something happens and act on it,” Kim said.

And while the positivity rates of surveillance testing remain very much worth keeping a close eye on, Miller said that, for now at least, trans-Pacific travel is proving largely safe.