At least 40 cases of the coronavirus have been linked to a wedding held in rural Washington earlier this month, a possible COVID-19 “superspreader” event that has left health officials begging all 300 attendees to quarantine.

The Grant County Health District on Wednesday confirmed to The Daily Beast that overnight, 23 more people have tested positive for COVID-19 in connection with the Nov. 7 wedding near Ritzville, Washington—a rural eastern Washington town with a population of only 1,649. Officials say the wedding has since caused a spike in COVID-19 in the area, and they expect more cases in the coming days.

“We have over 40 confirmed linked cases and we are asking all participants and the households of the linked cases to quarantine,” district administrator Theresa Adkinson said. “Due to the large surge in cases beyond just this one event, we are doing our best to make contact with cases but do not have a full scope of the impact of the wedding at this time. Most wedding participants are being cooperative and very helpful in quarantining their households.”

The Washington health department is now asking all wedding attendees to get tested and quarantine until Nov. 21.

“We are very thankful to those attendees who have gone in for testing and are staying home. This helps protect their friends, coworkers, and communities from this illness,” Adkinson said in a Monday statement, which added that while the health department is trying to notify attendees, it’s unlikely they’ll be able to reach everyone.

Under current COVID-19 restrictions, wedding ceremonies in Washington are limited “to a total of no more than 30 people.”

On Sunday, Washington Gov. Jay Inslee prohibited indoor gatherings and outdoor gatherings with more than five people from different households in an attempt to curtail the recent spike of COVID-19 cases that has spurred a “third wave” of transmission in the state.

“A pandemic is raging in our state,” Inslee said Sunday while announcing a slew of new COVID-19 restrictions. “Left unchecked, it will assuredly result in grossly overburdened hospitals and morgues; and keep people from obtaining routine but necessary medical treatment for non-COVID conditions.”

The new regulations, which will be in place for at least a month, also include a ban on indoor dining, bars, and gyms, as well as a warning from Inslee that flouting these mitigation recommendations for the holiday season could have catastrophic impacts on the state and its already overwhelmed health system. To date, 2,548 have died and 131,532 more have been infected with the coronavirus, according to the state Department of Health.

“Time is of the essence here; what we know is, if you act early you can save lives and if you don’t you’ll be swamped by a tsunami of the virus,” Inslee said. “This is in our hands, we make a decision whether this pandemic is going to swallow us whole.”

Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security who specializes in infectious diseases, believes the Washington wedding proves the perils of gathering in a pandemic that has already killed nearly 240,000 Americans.

“During these kinds of mass gatherings, where people are not fully social distancing, not wearing masks, and are drinking alcohol, it’s a perfect environment to see the virus spread,” Adalja told The Daily Beast on Thursday. “The bigger the wedding, the bigger the possibility for infections.”

Adalja added that while every person who attended the wedding should quarantine for at least 14 days, valuable time has already been lost to mitigate the COVID-19 spread.

“This is a significant spread, and I think it underscores that situations, where people put their guards down, is an opportunity for the virus to exploit them. And while a 300-person wedding is not a 10-person Thanksgiving dinner, it’s the same type of risk,” he said. “If anything, a Thanksgiving dinner is just a microcosm of this wedding and what can happen.”

And while few details of the Ritzville wedding have been released, the ceremony is now one of several to cause a significant outbreak. In August, a Maine wedding led to at least 177 cases and the deaths of eight people who did not attend the event, according to the CDC. In New York, a wedding and birthday party also led to more than 50 positive cases and nearly 300 in quarantine.

To combat the spread in Washington, the Grant County Health District is now urging wedding organizers in any county to keep a log of attendees in case a future outbreak occurs.

“Our personal decisions affect the health of our family, friends, and communities,” the Grant County Health District said.