One week after graduating to Tier 2 in the city’s reopening strategy plan, Oahu last week recorded coronavirus statistics that were good enough to meet the criteria of the less restrictive Tier 3 level.

But Honolulu isn’t going anywhere for at least another three weeks — and maybe longer if people can’t resist getting together Saturday night for some Halloween revelry.

“One night of letting your guard down can create a whole bunch of problems for all of us on this island and the state of Hawaii,” Honolulu Mayor Kirk Caldwell said Thursday at a news conference at Kapiolani Medical Center for Women & Children.

Caldwell and a couple of Kapiolani doctors urged people to avoid trick-or-treating and be otherwise cautious Halloween night to prevent spreading the virus.

In recent weeks Honolulu’s coronavirus numbers have been slowly declining even as the pandemic has started to rage on the mainland. Hawaii once again finds itself among the states with the fewest COVID-19 cases.

Despite the recent trend, a further loosening of restrictions isn’t happening on Oahu for at least three weeks, Caldwell said.

Honolulu’s four-tier reopening strategy requires a minimum of four weeks in one tier before it can move up to another level, he said, and it is the last two weeks that determine whether the city can move into the next tier.

“This tiered program is based on a conservative approach moving tier to tier,” Caldwell said. “I actually think it’s the way to go because it projects to people what to expect based on their actions.”

The seven-day rolling averages for the week ending Wednesday were 49 cases and a 2% positivity rate. Those numbers are good enough to qualify for Tier 3, which requires 49 or fewer cases and a positivity rate of 2.49% or lower.

Among other things, Tier 3 would increase social gatherings to 10 people from five and funerals to 25 from 10. Gyms and fitness facilities would be allowed to operate at 50% capacity, up from the 25% of the current Tier 2 level.

On Thursday, however, Oahu recorded 60 cases, bringing the seven-day average up to 50 cases, and officials are worried that Halloween could send the numbers further in that direction, just as previous holidays did.

Caldwell and the Kapiolani physicians urged residents to continue to wear face coverings, keep their distance and wash their hands.

“If we do these things, I believe we can stay below 50 cases and 2% positivity rate and move into Tier 3, and I believe we can even get to Tier 4. New Zealand has showed the way; South Korea has showed the way; and I think we can do it, too,” the mayor said.

Statewide, state health officials Thursday reported two coronavirus-related fatalities and 77 new COVID-19 infections, bringing the totals since the start of the pandemic to 215 deaths and 14,911 cases.

Both of the latest deaths were adult male Oahu residents who had underlying conditions and had been hospitalized, according to the state Department of Health. One man was in his 50s, while the other was older than 80.

Officials said they counted 4,854 tests in Thursday’s tally for a 1.6% statewide positivity rate.

In another COVID-19 development, testing of Hawaii inmates at the Saguaro Correctional Center in Eloy, Ariz., was completed Thursday for 1,011 inmates, the Department of Public Safety reported.

The results are expected to take up to three days, during which the inmates will remain in quarantine.

The number of Hawaii inmates in medical isolation at Saguaro with active COVID-19 cases is 61, with six of them hospitalized, officials said.

Elsewhere, the department reported one positive test result for an employee at Halawa Correctional Facility and one at Oahu Community Correctional Center. The results are part of ongoing mass testing for COVID- 19 at all correctional facilities statewide.