HONOLULU (KHON2) — The Delta variant continues to quickly spread across the United States mainland.

The highly transmissible virus is believed to cause more severe illness in those unvaccinated as well as in children, which continues to be rare.

But as Hawaii heads into the July 4 holiday, there are concerns it will spread more rapidly across the islands.

“There’s really an increased urgency to get vaccinated now, because it is here, we know it’s spreading,” explained Kauai District Health Officer Dr. Janet Berreman. “That’s what it’s done everywhere it’s gone, and it’s going to do that here.”

In just over a week, 13 Delta cases were confirmed by the state health department, but it took two to three weeks for the state to get lab samples back to confirm the variant had arrived; indicating that the variant has likely had the opportunity to spread statewide during the month of June.

“The virus is a little more transmissible, so if you’re not vaccinated, you’re going to catch it,” said Lt. Governor Josh Green. “And also, we’ve seen a slightly higher percentage of people going into the hospital. We believe when they catch Delta, there’s some speculation it will even be a little bit more serious for children.”

Those who are vaccinated are more protected from catching serious illnesses from any COVID-19 variant. The first Delta case in the state was in a vaccinated resident who did not have severe symptoms nor ended up in the hospital.

“The vaccine does stop Delta. So as a doctor, that’s the thing I can keep saying to people: get vaccinated so we drop our case counts down into the low teens or 20s,” Dr. Green urged.

That’s where the state was on July 4, 2020, with 25 COVID-19 cases. The Delta variant comes at a time vaccine urgency is declining, restrictions are easing, gatherings are increasing and the holiday weekend that sent case numbers skyrocketing to 300 plus is just one week away with 40% of the state unprotected.

“If you’re vaccinated, you’re fine. If you’re unvaccinated, you go to a big gathering, you’re going to catch COVID, so it’s pretty simple,” Dr. Green said.

Dr. Berreman added vaccinated people still need to be careful this holiday weekend.

Health officials hoped case numbers would have dropped significantly by July 4 with more people getting vaccinated, yet case numbers have remained consistent.

“I think that it’s possible that the delta variant is playing a role in that,” said Dr. Berreman. “The increase that we’ve seen on Kauai seems to be related to travel as all of our increases have been, but also to a couple of clusters, and we are still investigating whether there may be any role of the Delta variant in those clusters.”

Officials encourage residents who have questions about the vaccine to speak to their health care provider.