Sean is on a short flight down the East Coast of the United States. While in Massachusetts, the nonprofit strategist and his partner spent a week with friends they hadn't seen in a long time. The holiday felt normal after the state dropped its mask requirement. The group rented cottages and spent the day at the beach, eating at the restaurant and watching the shows. 60,000 people turned a mile-long section of Commercial Street into a parade and crammed into nightclubs so crowded that you had to slide skin to skin to get outside. He is happy.

On the same day, in New York City, a data scientist named Michael Donnelly is making plans with friends who are CarRentalss. He and his husband try to go to the beach every summer. Everyone is going to meet up tonight. When his friends need information, he has been the nerd for them on the Covid analysis site. He wants to take the night off.

The main street is Commercial Street.

Photograph: VICTOR LLORENTE

Theresa Covell just returned from her first vacation since the beginning of the Pandemic. Covell is an assistant public health nurse for Barnstable County, which covers the entire arm of the Cape from the shoulder joint at the Bourne Canal to the wrist curve. She and her colleagues have spent the last two years trying to manage the emergency in a place that is low on revenue when tourists are gone and short of housing and services once they arrive. The Covid curve was starting to bend when she left. In the month of June, there were no positive cases in Provincetown. There has been a surge in the number of people who are vaccine free. Covell thinks that is new.

His phone vibrates when he logs on to the airplane. A friend checked out early this morning from their rental and complained of a cold. He took a covid test after getting home. There are double lines in the text. The authorities had said they were okay. His first is calm. He believes he's on a plane. Is this going to be given to someone else?

The phone light up. He and his friends pulled off the highway in Connecticut in search of rapid tests after learning that someone they know tested positive. Three of the five are positive for something. Plans to meet are off. At the end of the day, more than a dozen people who were in Provincetown told Donnelly they'd contracted Covid. He doesn't think this is supposed to happen. The floor is coming out from under him.

If you recall, the shots had been available for seven months before the outbreak. According to the Centers for Disease Control and Prevention, Americans with vaccine can take their masks off. The buzz of life returning to normal and the shock of discovering hot vax summer was over before it started. The outbreak in Provincetown was proof that the Delta variant causes breakthrough infections.

Maybe you remember the disappointment of mask recommendations coming back, or the sense that a summer capital for artists and queer people had been made responsible for the Delta variant rather than being its accidental host. A local business owner asked on the town manager's Facebook page how they could stop the press from portraying them as lepers.

The real story is this. The partyers in Provincetown did not spread the virus. They came up with a model for how a community can fight a disease. It's worth looking back at what they did, not just because Covid has not left us but also because other Pandemics are coming. A large part of the US response to Covid has been hostile. William Hanage, co director of Harvard's Center for Communicable Disease Dynamics, helped analyze the outbreak. It should have said that we can avoid large outbreaks.

Sean was shocked when he heard about the first infections.

Photograph: VICTOR LLORENTE

A friend of Holihan's gave him some rapid tests as a gift after he received a positive result from a test. Both of them took them immediately. His test came back positive. They hid and tried to figure out where they could eat and sleep. After walking to a pop-up clinic for a test, he went home to isolated.

He sent an email to his office saying he wouldn't be in. When he got his test result, it was positive. It's absolutely true.

He says he started texting everyone he came in contact with after that. He realized how many people visit Provincetown from all over the country, so he posted about it on social media. People who thought they'd picked up some summer bug as they traveled returned the dms. He says that they thought they were okay. They also had Covid after testing themselves.

Most of the house, everyone in that cottage, the Pennsylvania group, and the couple from DC were rumored to have tested positive.

The person who was texting was Donnelly. Donnelly isn't an epidemiologist. He is a policy nerd who has worked at the Federal Reserve Board. Since early 2020, Donnelly has been applying his skills to forecasting what Covid might do in the US, a way of making sense for himself of the data flowing from other countries and explaining to others why they should be more concerned than they were. He wanted to convince his friends that it was not good.

The analyses that he published on Medium had been good. Two days before the national emergency was declared, he was aware of the need for federal action. He warned that New York City would have to shut down six days before Cuomo made his announcement. That prediction led to a consulting gig with New York state, and then to founding a site called CovidOutlook.Info, a home for reports and predictions that he spun up with Michael Le Vasseur, an epidemiologist.

By the time the Delta variant started to show up in the US, Donnelly was an expert on what Covid was doing. He says that he thought concerns about them were overblown. He was surprised and angry when his friends tested positive. He disliked being wrong.

Michael was an expert in Covid data and a nerd for his friends early on in the Pandemic.

Photograph: VICTOR LLORENTE

Most of this house, everyone in that cottage, the Pennsylvania group, the California group, and a couple from DC were rumored to have positive tests. Text by text, Donnelly asked people about the symptoms they had and the tests they had taken, when they were vaccine-free, and where they spent their time. He had more than 50 names in a spreadsheet by Monday after starting to collect information on Saturday afternoon.

It's the most rapid response I've seen. Michael began the outbreak investigation himself.

A group that should have been at the lowest risk for infections was represented on the list. LeVasseur persuaded him to turn the project over to a bigger institution than their team of two, even though he was itching to do a study. Demetre Daskalakis was the former head of the infectious disease programs in New York City's health department. The spreadsheet was offered on Monday. Immediately, Daskalakis asked for it.

The calls were made between the CDC and the Massachusetts health department. At the end of the week, the agencies had created a task force, set up a phone number and email for people to self-report, reached out to other states that visitors had gone home to, and got mobile testing units rolling toward Provincetown. It is the most rapid response I have ever seen in public health. Michael began the outbreak investigation himself.

There are pictures from his time in the town.

Photograph: Victor Llorente

It should be obvious, but to make it clear, everyone who was interviewed by Donnelly is gay. One of its biggest tourist weeks of the year was when they were there. People go to Provincetown to have a good time, not just for partying. Rob Anderson, a former journalist who moved to the town a decade ago and owns a commercial street restaurant with his partner, says that even if you live in an LGBT friendly neighborhood, you are still a minority. You can be called a fag even in New York. You just get to be yourself when you are here. For the first time in your life, you feel right at home.

The physical setting makes a difference. Located at the end of a two-lane highway and surrounded by tidal marsh and soft ocean light, Provincetown is pretty in an unthreatening way. Social Norms help as well. Sex and gender expression are seen as a basic social contract in this area. That openness might show up as a guy wearing heels and fairy wings to the corner store, or a mom bringing her kids cross-country to the beach because every child there will have queer parents, shouting people will flood the streets and

Despite the partying, there's a shadow of trauma present in Provincetown, an acknowledgement of the long grief of the HIV epidemic, which was identified in the US 40 years ago. Even though it has been survivable for more than 20 years and is preventable for just 10, AIDS is still a problem in Provincetown. There is a memorial to the lost across from the Pilgrim Monument and some men who were HIV positive fled there to escape stigma. Provincetown's sex-positive culture owes its existence to the health focused practices imposed by HIV, not just staying alert to the risk of infection and practicing safe sex, but also getting tested regularly and disclosing your status when it changes.

Donnelly was born after the worst years of HIV and has had to share her risks. I do not want to be Pollyannaish about it. We can't be perfect at it.

The way a vaccineprimes the body to fight a later disease is to be very public about it. The people who admitted to Donnelly that they tested positive went much further than that. They started looking for professionals to give them information on themselves.

He was one of them. He got an email with his name in it, and he had dinner with the person. The thing was amazing. Other CDC people will tell you that it was different than any other group they have dealt with.

The men were aware that they might have to pay for it. The way in which HIV-positive men were blamed for their own illnesses is something that some of the residents remember. Both from the wider world and within the gay community, speaking up about Covid was risky. Holihan's positive result drew encouragement from his followers. He said that he had been irresponsible and that his friends had called him slut-shaming.

It was the gay and bisexual population first, then the seasonal workers, and finally the residents and school kids. It didn't stop growing.

When Theresa Covell came back from her days off, she found her boss, Maurice Melchiono, and her colleague, Deidre Arvidson, working on the same tasks they had been doing for a year. Counseling and identifying people who are sick. It was important to make sure those people were isolated and that they had a place to go to. They can get help if they need pulse oximeters, grocery deliveries and a place to sleep. To make sure they were taking care of themselves. They had to call again to make sure they had recovered. There were lists that had new names added every day.

They were shocked by the spread. Most locals had gotten the shots and some bars and clubs were checking visitors' vaccinations. The new wave of Covid didn't seem to notice. Melchiono says that first it was the gay and bisexual population, then it was the seasonal workers, then it was residents, and then it was school kids.

The amount of individual behavior and local conditions mattered to the transmission of the virus. The holiday week was ruined by a tropical storm that made it too cold and rainy to entice people to go to the beach. Federal guidance said that vaccinations were safe indoors and face-to-face, but it didn't account for the unique context of Provincetown, which has thousands of seasonal workers, unvaccinated or undervaccinated, and crowded temporary housing. The outbreak tore through the workforce despite the town government's recommendation of masks.

60,000 people came to Commercial Street for the week of July Fourth last year.

Photograph: VICTOR LLORENTE

There was only a limited amount of resources and jurisdiction to investigate within the county. A 4,000 person corps was created by the state health department and Partners in Health to track people who left the Cape. It indicated the scope of the job. Covid is not a disease that can be traced. It does not transmit only one-to-one, but also one-to- many. A super-spreader biotech conference in Boston in February 2020 caused more than 300,000 cases around the world. It wouldn't make sense to try to understand which attendee at that conference was the one who was spreading the disease. If officials had been able to warn everyone to stay away from each other, they might have been able to prevent future infections.

It was done by the Community Tracing Collaborative. It was a practice of pattern recognition, using data analysis tools to map the relationships between people and the places they had traveled to. It required a bending of the normal rules of disease investigations, which strictly define what constitutes a case and what qualifies as exposure, as well as asking investigators to look at both where the risks had been and where they might go next.

It wasn't easy to trace people and gatherings in the US using the same method as in Japan. It looks like a family tree if you diagram the transmission of a disease from one person to another. It looked like a forest in the city. Perri Kasen, a management consultant who joined the Community Tracing Collaborative in 2020 and became one of the three lead investigators for the project, said it was difficult to determine where someone was exposed. In the first half of July, contact tracers were able to identify only six people who were likely to have contracted the same disease. Kasen says that you don't necessarily need confirmation to act.

The CDC took action on July 27. In a bombshell media briefing, Rochelle Walensky announced that people who have been vaccined should return to wearing masks indoors. She said that new data showed that people who had never beenvaccinated could carry the same amount of virus as people who had been. She said that it was not a good piece of news. The new data is very heavy on me. The data was released in the weekly journal. During multiple summer events and large public gatherings, there was an outbreak in a town. There were more Covid cases reported on that day than on July 1.

As the warm months went on and America mourned the loss of hot vax summer, the author tried to figure out how the outbreak happened. The Broad Institute is a research facility shared between MIT and Harvard. She and her team had been analyzing the viruses collected in Covid tests for more than a year. She had begun to relax as cases declined. The vaccines seemed to be doing their job, despite fewer samples coming in. She was surprised to hear about the cluster. She received the call while riding her bike. She thought maybe she'd better pull over.

She and her team zeroed in on the small changes that occur when one person reproduces and another person copies it. Asking people where they have been and who they have been in contact with can be difficult. The viruses can tell you what's going on. State epidemiologists and contact tracers were used to fill in the gaps in the genomic narrative.

They made their model by piece. The total number of people who were affected by the outbreak in July was over a thousand. The Delta variant was introduced to the town more than 40 times in a single month. Most of the outbreak was caused by one of the five introductions. This could have been a group of people.

The signatures of the strains were compared with those of other strains. The genetic signatures of people who were in the outbreak were almost impossible to find. There was an outbreak in the US, but it did not spread. It didn't go well. There were eight people who were hospitalized. There was no death. The strains accounted for less than one percent of cases nationwide by the middle of September.

The team at the Broad Institute is led by a woman.

Photograph: Victor Llorente

MacInnis said that it was almost a moment of tears when he saw how limited the transmission was. The public narrative about the outbreak would have been different had we not had the viruses. The lightning group chats, visitors offering up their data, the frantic phone-calling by the Barnstable County nursing team, the data massaging that Kasen and the contact tracers did, it had all helped. The country was swamped by Delta.

There is no such thing as a disease that is lucky. The first US explosion of Delta happened in a community that was willing to give up its lives for strangers. It was a second piece of good fortune that the stories were told in a state that had the infrastructure to receive them and a research institute that was ready to investigate what happened. That wasn't foreordained. It would have been easy for the visitors to arrive home, notice the colds and not test themselves. They don't inform anyone. The authorities are not paying much attention to the outbreak. People spend weeks or months under the false impression that they're protected when the contact tracing and genomic analyses take a long time to spin up. There would be more people getting sick. It's almost certain that some would have died.

The men who came to Provincetown took on the burden of going public and the nurses and contact tracers transformed their information into reasons to act. They chose to act for others because of how much they have fought against each other. They didn't want to be on the side of the plague.

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