Not so very long ago, being fully vaccinated against COVID-19 seemed to be the golden ticket. Prevention against the dreaded coronavirus seemed virtually assured — and even the U.S. Centers for Disease Control and Prevention eased its mask-wearing guidance, optimistically opining that fully vaccinated people could ditch their face coverings.

Alas, it all turned out to be overly optimistic, as the new delta variant roared through communities, more contagious and more deadly than previous strains. The CDC has since revised its masking stance, to match the increased risks associated with the surging delta strain.

The vaccinations remain highly effective, of course — proven to be powerfully protective in lessening COVID-19 severity should infection occur. At Hilo Medical Center, for instance, one of many hospitals where ICU beds are full, the average hospital stay for an unvaccinated patient is four weeks — a stunning toll on the human body, and on health-care resources. Clearly, this is not just a bad flu.

Still, no vaccine is an absolute shield, and in today’s case, not against delta. So precautions must be renewed — namely, the “3Ws” of wearing masks, washing hands and watching one’s distance from others.

COVID-19 infections here remain alarmingly high by Hawaii standards: On Friday, 845 new cases were reported, plus four deaths. And the state Health Department’s newest cluster report cited eight breakthrough cases in July: fully vaccinated residents infected by the coronavirus during social gatherings.

Four of the breakthrough cases were among a cluster of 16 individuals who attended an indoor band concert at an Oahu bar with “many attendees, intermittent mask wearing, and very little physical distancing.” In another July cluster event, four fully vaccinated residents were among 17 coronavirus cases linked to an indoor wedding reception.

The cluster report’s focus on community transition from social gatherings underscores the imperative to drastically curtail mingling outside of household members — even with friends and relatives perceived to be coronavirus-free, since delta is so highly transmissible.

To be sure, most of today’s severe cases comprise what health officials call “a pandemic of the unvaccinated,” with unimmunized people accounting for about 97% of COVID-19 infections and 99% of hospitalizations.

So protect yourself and loved ones by getting vaccinated today. And even after that, take all precautions to wear a mask, wash your hands and watch your distancing. Even as government leaders mull stricter rules on social interactions, self-responsibility remains key.