medicine machine manufacturers，medicine machine manufacturers，medicine machine manufacturers，medicine machine manufacturers，The July 4 holiday is always a huge celebration in the small town of Provincetown, Massachusetts, with a long lineup of parties and festivities that usually bring in thousands of visitors from across the country to the top edge of Cape Cod."That's what we kind of say is the official start of summer," said Christopher Roberts, who owns a puzzle and game store in Provincetown. "July 4 is just packed ... and then really from that day on, it's like that."Provincetown, home to roughly 3,000 year-round residents, was thrust into the national spotlight last week after it became the subject of a study that persuaded the US Centers for Disease Control and Prevention to change its face mask guidelines.Published Friday by the CDC, the study said 469 Covid-19 cases were identified in Massachusetts residents who had traveled to Barnstable County -- which includes Provincetown -- between July 3 and July 17. The cases were associated with "multiple summer events and large public gatherings," the CDC said.Roughly three-quarters of those cases were among fully vaccinated people, a finding that suggests inoculated people can also spread the virus, including the dangerous Delta variant that's been fueling the country's latest surge. There were five hospitalizations associated with the outbreak -- four of whom were fully vaccinated people -- and no deaths reported, the CDC study said.The agency updated its mask guidance last week to recommend vaccinated people wear masks indoors when they're in areas with "substantial" or "high" Covid-19 transmission to prevent further spread of that variant."I personally was under the impression that it would be difficult to contract (Covid-19)" after getting the vaccine, said Ken Horgan, a Provincetown hotel owner."But I was educated quickly, as all of us were here, getting vaccinated does not give you the ability to engage in high-risk activities or otherwise assume that you don't have to take any precautions," he told CNN's Alisyn Camerota on Friday.To curb further spread, local leaders have brought back a mask mandate for Provincetown, and fully vaccinated residents and business owners say they're doing their part to double down on safety measures again and push for more vaccinations.They say the cluster was a wake-up call that while the vaccine is very effective at preventing serious illness and death, it works best when paired with other precautions."We were told that if you're vaccinated, you're almost invincible and I think we ... wrongly assumed that," town manager Alex Morse CNN's John Berman on Friday.'A petri dish for the country'Debbie Nadolney, director and curator at the AMP Gallery in Provincetown, said while she, her partner and most of the other people she knows in town have been vaccinated, she felt mask requirements and other safety measures were lifted too soon. She said she mostly continued to wear her mask after her vaccine and encouraged others to do so when they were in the gallery."It just seemed to me like common sense to continue on," she said. "Only half the country ... has been vaccinated, we haven't reached, you know, the 70 or 80% vaccination rate in the country yet. So why are we celebrating?"Roughly 57.5% of the US population has received at least one Covid-19 vaccine dose and about 49.5% is fully vaccinated, CDC data shows. In Barnstable County, roughly 76% of people have received at least one dose of their Covid-19 vaccine, according to the latest state data.With the influx of people the town saw in July and no widespread mask requirements, Nadolney said the outbreak didn't surprise her. Local leaders held an emergency meeting last week and issued an indoor mask mandate for Provincetown. The requirement applies to all indoor restaurants, theater or performance venues, bars, dance floors, lodgings, fitness centers, retail and personal service shops, offices and other public facilities.Nadolney said she now mandates masks in the gallery and hopes the town's mandate isn't lifted any time soon. Doing away with mask requirements was a "mistake" in the first place, she said, and she hopes other parts of the country learn from the town's experience and require masks in addition to pushing for more vaccinations."Provincetown is such a little place but obviously we've been a petri dish for the country," she said.Roberts, who owns the puzzle store, said he's enforcing the mask requirement and if customers don't have a face covering, employees will offer one to them. Now that he knows vaccinated people can spread the virus, too, Roberts said he's extra careful not to get infected since his 7-year-old son is still ineligible for a Covid-19 shot.