What to Know
- The delta variant has been found in 41% of positive NYC samples studied, up from 26% in the health department's last report; the week before that, delta was found in 17.1% of samples tested
- That strain is now the dominant one in New Jersey as well, accounting for 40.7% of samples sequenced in the last four weeks, up from 26.8% a week ago and 7.3% two weeks before that.
- Existing vaccines have proven effective protection against the variant; virtually all new COVID deaths and hospitalizations are among unvaccinated people, officials at all levels of government say
The highly transmissible delta variant is now the most dominant COVID-19 strain in New York City, soaring from about a quarter of tested positive samples to more than 40% in a week as the five boroughs' rolling seven-day case average surged 62%, according to new health department data out Friday.
As of Friday, the delta variant that first devastated India before spreading globally -- and is thought to be up to 60% more contagious than that first widely tracked alpha variant -- accounts for 41% of citywide samples tested in the last four weeks.
That's up from 26% in the city's variant report a week ago and up from 4.9% in about six weeks, a rise reflective of a national trend that saw delta emerge as America's most dominant COVID variant last week.
It took only 14 days for delta to vault from the fourth most common COVID strain in the city to the first, overtaking first the so-called New York City strain that initially emerged in Washington Heights before spreading elsewhere, B.1.526, then gamma, formerly known as the Brazilian strain, P.1 and now alpha.
Scientific evidence has shown delta spreads far more easily than earlier strains of the virus and causes more severe outcomes for those infected, prompting renewed pushes at all levels of government to get people vaccinated if they haven't been.
Delta, the variant that was first found in India and is now in at least 104 countries, has dramatically increased its prevalence across the U.S. over the last month, accounting now for well more than 50% of tested samples, according to the CDC.
The World Health Organization, which has called it the "fastest and fittest" variant yet, expects it to become the dominant strain globally.
Given the relatively minute subset of positive samples sequenced to assess potential strain variations, both CDC and local experts believe the prevalence of delta, which is classified as a variant of concern, to be much higher than reported.
The variant is being blamed for a surge in cases across the United States that has seen cases double over the last three weeks following months of decline. All but two states -- Maine and South Dakota -- have reported case increases in the past two weeks. While hospitalizations and daily deaths remain comparably low, those are lagging indicators and may rise as delta spreads in unvaccinated areas.
The latest data from the CDC shows they already are on the increase. Hospital admissions are up 36%, while deaths rose by 26% last week nationwide, with nearly all cases being among the unvaccinated, the agency said Friday.
"There is a message that is crystal clear: this is becoming a pandemic of the unvaccinated," CDC Director Rochelle Walensky said. "We are seeing outbreaks of cases in parts of the country that have low vaccination coverage because unvaccinated people are at risk."
Just four states drove 40% of new cases last week, with one in five coming from Florida -- and the White House says the Biden administration believes cases will continue to increase in the weeks ahead because of viral spread within low vaccination rate communities.
Existing vaccines are expected to protect people against delta and other variants of concern that have emerged, but with just about 68% of U.S. adults having received at least one vaccine dose and less than 60% fully immunized, delta's heightened transmissibility and associated risk has renewed concerns.
In New York City, the new seven-day case average this week is up 62% from the seven-day average the four weeks prior, city health data shows. Last week, that average was up just 32% in the same time frame. Hospitalization and daily death averages are both down in the latest period of study versus the previous week.
In New York City, where state data shows almost 65% of the adult population is fully vaccinated and more than 70% have had at least one shot, officials are warning of delta and doubling down on their message to get vaccinated with a sense of urgency that has been absent from the mayor's briefings the last month.
"We see overwhelmingly people have done the right thing," Mayor Bill de Blasio said when asked Friday on his weekly radio segment on WNYC whether restrictions need to be reinstated. "What's working for us is to constantly report the facts as we're seeing them, and if we see something we need to change we'll call people to arms."
De Blasio pointed to a preprint analysis of a new, not-yet-peer-reviewed study out of Yale and the Commonwealth Fund earlier this week that he says shows New York City's vaccine rollout has saved more than 8,000 lives and prevent hundreds of thousands of new cases of COVID in the five boroughs.
In a lengthy Twitter thread, he outlined a number of steps the city was taking to get vaccination rates even higher, including deploying mobile sites to under-vaccinated communities, unleashing door-to-door canvassers to spread the message and offering in-home vaccination services to any eligible New Yorker who wants them.
The city has also expanded its referral bonus program for local nonprofits and focused acutely on driving private practicing doctors to encourage their patients who haven't yet gotten vaccinated, for whatever reason, to get dosed now.
Now is an opportunity to sustain the city's progress against COVID-19, de Blasio says, and leverage existing vaccine effectiveness to curtail delta's spread.
Statewide, new daily COVID counts are closer to 1,000 the last few days than the roughly 300 to 400 Gov. Andrew Cuomo was reporting just a month ago. Daily deaths, for now, have reminded low. The governor reported just two new virus fatalities Friday, only one of them in the city, while total hospitalizations (460 as of Friday) are well below the 410-threshold that opened the pandemic in March 2020.
Core viral rates are consistently at or near all-time pandemic lows in New Jersey as well. Like New York, the Garden State does monitor variant data, and like New York, it has seen the prevalence of delta rise throughout the state in recent weeks.
That strain is now the dominant one in New Jersey as well, accounting for 40.7% of samples sequenced in the last four weeks, up from 26.8% a week ago and 7.3% two weeks before that.
Gov. Phil Murphy has repeatedly declared new COVID cases, hospitalizations and deaths in New Jersey to reflect "a pandemic of the unvaccinated."
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Data: City of New York, State of New Jersey • Nina Lin / NBC