Hawaii COVID-19 cases keep falling but experts warn subvariants could bring another surge

Jul. 7—Hawaii's downward trend in cases appears to continue, with lower average counts and positivity rates than the previous week.

The Hawaii Department of Health on Wednesday reported the seven-day average of new cases at 651 compared with 685 reported June 29, representing a decline for the fifth week in a row. The state's average positivity rate also dropped to 15.1 % from 16.5 % reported the previous week.

It was the fourth weekly decline in a row, but represented tests performed over the Fourth of July holiday weekend, when testing rates dropped.

"We are happy to see cases coming down over the last few weeks—overall, case numbers declining, " said State Epidemiologist Dr. Sarah Kemble. "That being said, we do see some slowing in the rate of decline now, and so that raises the question of whether we may be hitting more of a plateau at this point."

Hospitalizations of patients with COVID-19 also dropped to 164 on Wednesday, according to the state's dashboard, compared with 207 reported June 29. Of the 164, 12 were in intensive care and six on ventilators.

The seven-day rolling average for the week was at 183, according to the Healthcare Association of Hawaii, with about 27 new COVID-19 admissions per day.

DOH also reported 20 more coronavirus-related deaths, bringing the state's COVID-19 death toll to 1, 524.

These represent deaths reported to DOH over the past week, Kemble said, but may have occurred in previous weeks, not just over the past week.

"These deaths are not really changed in character from what we've seen previously, " she said. "We're still seeing deaths predominantly in older age groups."

She urged eligible people over 50 to get their second booster doses for protection against severe outcomes from COVID-19.

"Right now, we do know that the currently available vaccines still reduce your risk of getting severe outcomes from COVID-19, including hospitalization and death, " she said, "so the best thing to protect yourself is to be up to date on your COVID-19 vaccines."

All eyes, however, are on more transmissible omicron subvariants BA.4 and BA.5—particularly the latter.

The World Health Organization's director-general, Tedros Ghebreyesus, on Wednesday said that in Europe and America, BA.4 and BA.5 are driving waves, while in India, a new sublineage dubbed BA.2.75 has also been detected.

BA.4 and BA.5 are estimated to be about 1.6 and 1.8 times more transmissible, respectively, than BA.2, with an increased ability to evade antibodies elicited by vaccination or prior infection.

BA.4 now makes up 16.5 % and BA.5 53.6 %—or 70.1 % combined—of new coronavirus cases in the U.S., according to the Centers for Disease Control and Prevention.

Kemble said based on what's happening on the U.S. mainland, it's likely BA.4 and BA.5 will continue to gain a foothold in Hawaii. Whether BA.4 and BA.5 will cause another surge in Hawaii, however, is less certain.

"In some countries and jurisdictions, that has been the case—for example, in South Africa—whereas in other jurisdictions, it's less clear that's driving increased numbers of cases, " she said. "In Hawaii, I would say one thing that is going for us in a sense is that we've already had surges of BA.1 and BA.2 recently so there's some cross-immunity. But I do think we'll have to see if we begin to see more impact in terms of hospitalizations and severe outcomes as we begin to see more BA.4 and BA.5."

Masking, she said, remains a useful tool for reducing one's risk of getting COVID-19, along with staying up to date on COVID-19 vaccines. While there is a national discussion on new approaches to the vaccine to address more contagious subvariants, they are "speculation at this point, " she said.

On Wednesday, DOH reported that 76.7 % of Hawaii's population had completed their primary series of COVID-19 vaccines, with 43.3 % boosted once and 9.4 % boosted twice. Approximately 1 % of Hawaii's roughly 80, 000 keiki under 5 have gotten their first shots.

The Hawaii Pandemic Applied Modeling Work Group, a volunteer group of scientists, warned in a June 30 report on long-term scenarios that the virus "is still extremely unpredictable."

HiPAM said Hawaii can expect a new surge due to the more contagious omicron subvariant, BA.5, which was detected in the state back in May.

"It is important to understand that with each new variant we are facing a new situation, " HiPAM said in its report. "The virus is exhibiting a unique capacity to adapt and outmaneuver the immune response. Any proposed scenario is therefore speculative and should be taken with high caution."

BA.5, however, is of more concern because it is edging out BA.4, according to Dr. Bob Wachter, chair of the Department of Medicine at the University of California, San Francisco.

Wachter said in a Twitter thread earlier this week that "it seems clear that BA.5 will lead to an ongoing plateau, if not a moderate surge, lasting through summer and into fall."

Risks of reinfection increase with the presence of BA.5, and a recent study has found that health risks increase with each reinfection.

Although vaccinations and boosters are still "hugely valuable " in preventing a severe case that might lead to hospitalization and death, its value in preventing transmission is now far less than it once was, he said.

However, he still recommends those over 50 not wait to get a second booster due to recent data that shows it results in a powerful increase in protection from deaths. Additionally, he said that a second boost should not prevent one from being able to get an updated two-strain booster when it becomes available.

DOH on Wednesday also reported 4, 381 new COVID-­ 19 infections over the past week, which was lower than the number reported the previous week.

By island, there were 2, 832 new infections reported on Oahu, 516 on Hawaii island, 540 on Maui, 205 on Kauai, eight on Molokai and one on Lanai. An additional 279 infections were reported out of state.

The new infections bring the total since the start of the pandemic to 313, 076 cases.