The state Department of Health on Friday issued a special-edition COVID-19 cluster report regarding recent outbreaks associated with school events — in particular, a high school prom that resulted in both coronavirus and influenza infections.

While the DOH ceased issuing the biweekly cluster reports in early January, it’s now releasing reports if special circumstances warrant them.

“With case counts on the rise, the state has noticed an uptick of clusters associated with large school events,” said health officials in the report.

Since April 1, the DOH said, the state has investigated 27 clusters associated with schools and school-sanctioned events statewide. One-third of them are related to high school proms.

In April a high school on Oahu contacted the Health Department for assistance when 37 students who attended their prom reported being sick with common respiratory symptoms. Upon investigation, health officials determined that students were infected with both COVID-19 and influenza. The DOH did not identify the school.

More than 300 people, including students and chaperones, had attended the prom, where mask use and social distancing were reportedly not practiced. More than half, or about 57%, of the prom attendees had received a primary series of COVID-19 vaccine.

Most of the students experiencing symptoms had taken either a home COVID-19 test kit or went to a laboratory to get tested.

The DOH was able to confirm that six tested positive for COVID-19 and four tested positive for influenza A, while one tested positive for both. Due to limited testing, state health officials said the number of infections was likely higher than reported.

Noting that influenza activity has been increasing throughout the state and that co-infections can occur, the DOH recommended that those attending large school gatherings such as proms stay up to date on their COVID-19 and flu vaccinations, and not attend if feeling sick or exhibiting symptoms.

Some ways to help prevent an outbreak are to test for COVID-19 beforehand, to maintain masking indoors and social distancing, and to make sure the gathering venue has good ventilation. Masking upon return to school after the event will also help prevent subsequent spread, DOH said.

In a separate cluster case, health officials investigated an April outbreak associated with another high school prom on Oahu.

It involved 16 COVID-19 cases associated with a prom with 600 attendees, including students and chaperones. Mask use was required indoors except during food service.

Ten people tested positive for the coronavirus, while another three experienced symptoms and were epidemiologically linked to the outbreak. Additionally, three secondary cases were identified among household contacts.

The DOH said both schools required prom attendees to be vaccinated with the primary series of COVID-19 vaccines or to submit a negative test taken within 48 hours of the event. But both proms were held indoors, which can contri­bute to higher risk of COVID-19 transmission.

Many of Hawaii’s public schools are implementing their own COVID-19 health and safety rules for events as the academic year comes to a close. Kaiser High School, for instance, required its senior prom attendees to not only wear masks, but to follow a “no physical contact while dancing” rule. But the rules can vary widely from school to school.

The prom clusters occurred when infection rates in the isles were starting to climb and accelerate again, driven by the presence of more contagious omicron variants such as BA.2, BA.2.12 and BA.2.12.1.

On Wednesday the DOH reported 4,249 new COVID- 19 infections over the previous week, bringing the total since the start of the pandemic to 252,654 cases.

The state’s seven-day average of new cases was reported at 485 — marking the sixth consecutive weekly increase. The state’s average positivity rate, meanwhile, jumped to 11.5% — the seventh weekly increase.

The state Department of Education said in a statement that students’ health and safety continue to be the highest priority for public schools.

“There are a variety of factors that are taken into consideration when safely planning large events like commencement ceremonies and proms,” said DOE in an email statement. “The Department’s guidance on safety protocols for such events was designed to provide schools with flexibility as we continue to monitor COVID-19 conditions. While we want to be sure that our students can continue to celebrate these special occasions that they deserve, it is a collective effort to ensure that this is done safely.”

The department has received 750,000 home test kits and distributed more than 400,000 to schools during this season of special events.

Despite some protests, DOE intends to keep indoor masking requirements in place for all students and staff through the end of the school year.

While proms accounted for one-third of April’s cluster, certain classroom settings also accounted for one-third of the tally. Early child care settings and athletics each accounted for 11%, and much of the remainder was related to other large gatherings.

In eight classroom clusters, there were some factors in common that included masks being optional, students being in close proximity to one another, and people present at school while sick.

“Classroom environments have a low risk of COVID-­ 19 transmission when the school implements layers of mitigation measures — vaccination, staying home if you are sick, correct and consistent mask use indoors, social distancing, and increased ventilation,” said DOH. “In the classroom setting, students are recommended to maintain at least three feet of physical distance between students, and with closer proximity, masks are an effective tool to reduce the spread of COVID-19 in the classroom.”