The most common strain of COVID-19 now circulating nationwide, and in New Jersey, spreads more easily than viruses that cause the common cold, seasonal flu and smallpox, and is roughly as contagious as chickenpox, according to recent media reports. It also packs the nose and throat — where it can be easily disseminated by sneezes or coughs — with 1,000 times more viral particles than the form of coronavirus circulating last spring.

These are among the disturbing new facts about the COVID-19 delta variant that emerged Friday in news stories based on research conducted by the federal Centers for Disease Control and Prevention, which the agency used as justification for revising national masking guidelines last week. Gov. Phil Murphy and state health commissioner Judy Persichilli also recommended New Jerseyans mask up when indoors among people who may not be immunized, regardless of their own vaccination status.

It was not clear Friday if state officials planned to implement other infection-control measures based on the latest CDC research. Officials at the state Department of Health declined to say if additional restrictions were under consideration.

Dr. Edward Lifshitz, who leads the department’s communicable disease service, noted that delta is currently the most contagious coronavirus variant known so far. And, Lifshitz said in an email to NJ Spotlight News, the delta variant is nearly as infectious as measles, the most contagious virus currently known.

Return to infection-control measures

Several public health experts said that while news of the delta variant’s unique powers is not surprising, it underscores the need to keep close-fitting masks handy and revisit other, once-common infection-control measures like hand-washing and social distancing. They also stressed the importance of COVID-19 vaccinations, as the shots are highly effective in preventing serious illness and death — even if immunized individuals can still spread the delta variant. Plus, protecting society against the new variant requires a higher level of community immunity, according to one epidemiologist.

“Delta is a different beast in terms of how infectious it is. And it’s much more worrisome,” said Dr. Stanley H. Weiss, an infectious and chronic disease epidemiologist and professor at the Rutgers New Jersey Medical School and the Rutgers School of Public Health. Weiss said controlling this more virulent strain also requires a greater commitment to systemic changes, like improving ventilation systems to reduce spread, and providing booster shots to individuals who have received COVID-19 vaccinations but remain at greater risk than the general public because of their age or health status.

“This pandemic has clearly not gone away yet,” Weiss said. “I think we can anticipate that other variants may evolve over the coming months and years that may be even more dangerous than the delta variant.”

New cases on the rise

In New Jersey, the coronavirus transmission rate, or RT — a measure of spread — has risen to levels not seen since last spring. The number of daily COVID-19 diagnoses, on the rise since early July, has exceeded the new case counts recorded on the same days last summer, according to an NJ Spotlight News analysis of state data. And on Thursday, new cases topped 1,000 for the first time since May. Hospitalizations and deaths also increased in recent weeks but remain at levels far below those reported in 2020.

“It’s very concerning because the strain of the virus that filled up our hospitals last year and triggered a shutdown of almost everything we’ve been doing in this state is almost half as transmissible as the delta variant we’re seeing now,” Dr. Shereef Elnahal, president and CEO of University Hospital in Newark, told NJ Spotlight News reporter David Cruz in an interview Friday.

Elnahal, the former state health commissioner, is hopeful New Jersey will not need to return to previous pandemic restrictions.

What’s happening in hospitals

“But the real marker on that is when hospital resources get strapped again,” he said, something that hasn’t happened at University Hospital, which now has fewer than 10 COVID-19 patients.

Elnahal credits the state’s relatively high vaccination rate — more than 70% of adults have been inoculated against the virus — with keeping down the number of hospital admissions and fatalities. While NJ Spotlight News found that “breakthrough cases” — or infections — as well as hospitalizations and deaths among vaccinated individuals have occurred more frequently in recent weeks, most of the people who got very sick and die are not immunized.

“I do want to reinforce that vaccines are still the path that will ultimately get us out of this pandemic,” Elnahal said, a view he said hasn’t changed as more details come out about delta. “They are the one ray of light in this.”

Working toward community immunity

Epidemiologist Stephanie Silvera, a public health professor at Montclair State University, said that given delta’s characteristics, New Jersey probably needs to vaccinate around 80% of all eligible age groups — vaccines are now approved for ages 12 and older — to reach community, or herd, immunity, a point at which sudden spikes in new cases are much less likely. “We’ve plateaued well below where we need to be. And that was before the delta variant,” Silvera said of the state’s immunization progress, which has slowed significantly in recent months.

According to reports by The New York Times and other media outlets, the delta variant spreads faster than many common viruses and packs a hard punch in the high number of viral particles it generates in people’s noses and throats. That makes the virus easier to spread and harder for blood-borne antibodies triggered by vaccination to counteract the infection, experts suggest.

This “high viral load” is considered a main driver of spread via immunized people and a particular concern to Elnahal. “The question of why vaccinated people can spread the virus, even if they don’t get sick from it, is a real one,” he said. “And that’s the real public health concern around the reason that the [CDC] recommended indoor masking in areas where there is high or substantial spread.”

Well-fitted masks, limiting close contact

Weiss stressed that to protect against delta, these masks need to fit well, like the N95 versions that are designed to cup the face and filter out almost all particles. He also urged people rethink previous guidance, like the recommendation to spend less than 15 minutes in close contact with unmasked individuals.

“That’s thrown out the window now,” Weiss said, noting that delta can be transmitted very quickly.

No vaccine, including the highly effective ones that protect against COVID-19, is 100% effective, experts note, underscoring the need for masks, distancing and other infection-control protocols. Lifshitz, with the state’s health department, said these are particularly important for people whose immune systems are compromised.

“It is not a giant wall between you and the virus. It’s keeping you from getting severely ill and dying,” Silvera said of the shots. “We have to go back to that layering of public health measures. It’s like layers of Swiss cheese: all these measures have holes and when you layer them, the holes get smaller.”

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