“This communication… challenges the assumption that high universal vaccination rates will lead to herd immunity and prevent COVID-19 outbreaks… In the outbreak described here, 96.2% of the exposed population was vaccinated. Infection advanced rapidly (many cases became symptomatic within 2 days of exposure), and viral load was high.”

SOURCE:

https://eurosurveillance.org/content/10.2807/1560-7917.ES.2021.26.39.2100822#html_fulltext

Notable in this case is what seems to be a record breaking viral load from this study's patient zero, which very much contrasts the generally mild viral loads among the few cases of vaccinated infections:

A vaccinated dialysis patient was admitted to Meir Medical Center - a large Israeli hospital near Tel Aviv - with fever and cough. He remained on the dialysis unit for days, as his condition worsened. (One of many problems with overselling the vaccines is that it led to mistakes like this.)

By the time he was diagnosed with Covid-19, he had infected three fellow patients. He also had a PCR threshold of 13.6 - almost impossibly low, showing viral loads roughly 1 million times those in a lightly infected person. He was moved to a Covid-19 ward, where he eventually died [....]

Ultimately, 39 out of the 238 exposed vaccinated people (16 percent) were infected, along with 3 out of 10 unvaccinated people - a difference that doesn’t reach statistical significance because the unvaccinated group is too small.

Of the infected, 23 were patients and 19 staff. The staff all recovered quickly. But five patients died and another nine had severe or critical cases. All were vaccinated. The two unvaccinated infected patients both had mild cases.