The district said at least half of the cases were linked to the prom held last Saturday.
"We take the approach that the pandemic is not over and I think a lot of folks would agree with that," said district spokesperson Andrew Jenks. "That means that you still keep an eye on what the numbers are, what the local conditions are, the case counts and other metrics and criteria and follow the guidance of the health experts."
The district consulted with the Orange County Health Department before reinstating masks temporarily until April 22.
"We believe that the masks back on will slow the rate of transmission and hopefully we'll come out on the other side of this better than we are this week," Jenks said.
Approximately 87 cases were identified throughout the district as of Thursday with an estimated 37% at Carrboro High.
Jenks said it's still too early to decide whether the cluster will lead to tighter restrictions at other proms and large events throughout the district.
"We're going to take a look at this particular instance just see how much, if any, was directly because of prom. I mean, we think there's a likely connection to it, but we don't want to just blame prom, right? I mean there could be other factors. That being said, we'll take a look at it and if there are some changes or recommendations that can be put in place at other events, we'll do that," he said.
The increase in cases comes two weeks after the district's Spring Break. Health experts previously told ABC11 that they feared a rise in cases following Spring Break.
"I am anticipating that with the increase in travel and changes in patterns with spring break and several holidays coming up, we are likely going to have an increase in cases and potentially hospitalizations over the next few weeks," said Dr. Julie Swann, a professor at North Carolina State University who has tracked models throughout the pandemic.
Dr. Mike Smith is an infectious disease doctor with Duke who has worked with districts across the state to develop the best COVID-19 practices as part of the ABC Collaborative. He said he thinks the district made the right move opting back into masks temporarily.
"I think this worked really well here. What I do think it's kind of a call to action, though for other school districts across the state, other communities across the state to really have a sense of kind of what metrics are you going to use to make these decisions," Smith said.
Durham Public Schools also had Spring Break two weeks ago. The district has no clusters and around 40 positive cases, according to the most recent data from April 4-10. The district said it is not changing any protocols right now but is continuing to recommend masks at end-of-the-year events.
Wake County Public Schools is on Spring Break this week and did not confirm if they would be changing any protocols. The district isn't reporting any clusters. The last cluster reported was last December.
Johnston County Public Schools said it is not making any changes to its practices at this time. The district reported 19 positive cases this month between students and staff.
Orange County Schools identified 37 cases this week with around a third connected with Hillsborough Elementary School.
"Each district, each community, kind of has slightly different levels of risk tolerance when it comes to COVID. I think you need a plan. It's much better to have a plan and maybe you never need to enact it, that's the best-case scenario, but not having a plan and waiting for something to happen, I think gets you in trouble," Smith said.
He encouraged districts to be proactive and continue to monitor the metrics. He also said for families and students can continue getting vaccinated and wearing a mask to ensure safety at upcoming events.
"Had this happened in 2020, Carrboro High School would be closed right now," Smith said. "The fact that we've learned about this and, and kind of know what we're doing, it's a reminder that we're not out of this yet, but I think with planning and some thinking ahead, you can prevent, you know, more severe outbreaks from happening."