On Wednesday, July 28, New Jersey's rate of transmission of COVID-19 was reported at 1.51, its highest reading since the earliest days of the pandemic when testing was scarce and public health precautions were few.

Since then, it has slid down into the 1.3s, although that still signifies "exponential spread" and is well above the state's benchmark of 1.0 to judge whether the outbreak is expanding or contracting.

Despite more than 70% of New Jersey's adult population now being fully vaccinated, as Gov. Phil Murphy desired and achieved earlier in the summer, the spread of the Delta variant among the unvaccinated and vaccinated has driven persistent increases in positive test results and hospitalizations even as the rate has gone down.

Delta is responsible for nearly 84% of all sequenced variant cases in the last four weeks, according to New Jersey's information dashboard, but even more testing and sequencing may be needed to have a better sense of where this particular strain is going next.

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That's according to Dr. Stanley H. Weiss, professor of medicine at Rutgers New Jersey Medical School and professor of biostatistics and epidemiology in the Rutgers School of Public Health.

"We need much more surveillance of that type to understand and predict what's going to happen, and also to be on the lookout for other variants that might enter our community," Weiss said.

Prediction of Delta has been tricky, according to Weiss, who said it's accurate to say the variant was spreading far more and far prior to when New Jersey really took notice.

That eventually included, also on July 28, Murphy and the state Department of Health strongly recommending masks be worn indoors once again, by both the vaccinated and unvaccinated.

Many are looking across the pond for answers. On July 19, the United Kingdom reopened fully, a decision that continued to be adhered to despite concern and even ridicule from public health experts far and wide, given Delta's stronghold.

Yet as of Friday, according to the U.K. Office of National Statistics figures reported by the Associated Press, hospitalizations were down 13% in a week, with positive cases falling as well.

Nearly 74% of adults in the U.K. are fully vaccinated, close enough to the 71% reported in New Jersey by the Centers for Disease Control and Prevention to provide a hopeful parallel.

But it's not that simple, Weiss said, pointing to highly-vaccinated Israel as a more somber example.

"They've also had a surge of cases, and they've had many people hospitalized with COVID who are doubly vaccinated," he said. "So the different pictures we're seeing in different places don't really all jell."

One thing New Jersey may actually have working in its favor is the "lightning speed" with which Delta has moved, particularly looking at India, where the variant originated and spread at a time when vaccinations were few.

That suggests this spike may be quicker than others, but Weiss even cautioned against putting too much faith in that, recalling how this variant took over from others that had previously been dominant.

"If there's a dip, that gives a chance for other variants that might arrive to find a new niche and spread again," he said.

As there will always continue to be a portion of the population that either will not or cannot get a COVID-19 vaccine, Weiss suggested that businesses redouble their efforts to upgrade their heating, ventilation, and air conditioning systems.

This would also be in the spirit of prediction and preventiveness, he said, and would provide protection to all regardless of vaccination status.

"Future rounds of COVID could also be spread by respiratory root, so I think it's still necessary to make changes in our basic infrastructure related to our HVAC systems," Weiss said.

And even though we would all like to know where COVID-19 is going next, Weiss said it is still going to take time to fully understand the ups and downs of the virus and its mutations.

Patrick Lavery is New Jersey 101.5's afternoon news anchor. Follow him on Twitter @plavery1015 or email patrick.lavery@townsquaremedia.com.

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