Happy Nice Mall

They were gold miners in French Guiana, revelers and Indian health workers in Cape Cod. Although they lived in separate worlds, they had two things in common. All vaccinated against covid-19. And they all became part of the infection clusters.

In recent weeks, cases like this prove that chains of Covid-19 transmission and over-spread events can happen even now. groups in which almost everyone is vaccinatedare sounding alarms among paramedics and undermining hopes of returning to work as quickly as ever in the US.

In May 2021, the CDC told vaccinated Americans that they could remove their masks, but on Tuesday the agency said it had reversed course. vaccinated people should wear masks in closed public environments.

That’s because investigators learned from an outbreak in Provincetown, Massachusetts, a coastal town on Cape Cod that hosted a rowdy parade and weeks of crowded pool parties in early July. Health researchers say that since then, there have been more than 800 cases of covid-19 linked to these events, of which 74% were in people who were vaccinated.

The Provincetown outbreak was caused by the so-called delta variant, which now accounts for most cases in the United States. In a statement released today, CDC chair Rochelle Walensky said the “significant discovery” was that vaccinated people infected with the delta in Provincetown appeared to have as much virus in their systems as unvaccinated people.

“High viral loads increase the risk of transmission and raise concerns that, unlike other variants, vaccinated people infected with delta may transmit the virus,” he said.

The advice suggests a swift return to a layered countermeasure approach, including masks and social distancing, which could also complicate school reopening in the US from next month.

Infection in the gold mine

Studies around the world are building evidence of epidemics among those who have been vaccinated for weeks. For example, a science team in Paris and French Guiana recently announced how covid-19 pierced a South American gold mine in May, even though nearly all miners had received the Pfizer vaccine.

Despite being vaccinated, 60% were infected by a variant called gamma. This surprised scientists so much that they checked to see if the vaccines were damaged during shipping, but it didn’t.