By Nic Querolo

Covid-19 infections in New York City are climbing for the first time in months as the delta variant gains traction and vaccination rates in some boroughs remain stubbornly low.

The city’s seven-day average rate of positive tests has risen slowly throughout July, and had roughly doubled in two weeks to 1.27% as of Saturday. On average, there were 328 new confirmed and probable cases daily over the past week, up from 208 as of June 28.

That’s a far cry from spikes this year when city officials reported thousands of cases per day, and the positivity rate is below the national level of 3.4%. But the trendline is concerning, given the possibility of variants spreading in pockets of the city where fewer residents are vaccinated.

“The spread of the delta variant means that it is perhaps the most dangerous time to remain unvaccinated,” Dave Chokshi, the city’s health commissioner, said at a virus briefing Monday. “That’s why we have ensured that our vaccination efforts are proceeding with as much urgency as possible.”

Mayor Bill de Blasio failed at his goal of vaccinating 5 million New Yorkers by June. By mid-July, only 4.4 million New Yorkers are fully vaccinated, or 53% of the population. Meanwhile, the inoculation rate has plummeted to around 16,000 doses a day from more than 100,000 in April.

Staten Island has emerged as a miniature hot spot, with its seven-day positivity rate averaging 2.34% as of July 8, well above the citywide average. The borough’s Great Kills and Silver Lake/St. George neighborhoods had the highest hospitalization rates in the city in the latest 28-day period reported, May 31-June 27.

Chokshi said younger, unvaccinated people in Staten Island are a primary cause. Less than half of the population is fully vaccinated, as is the case in Brooklyn and the Bronx.

About 26% of cases tested over the past 4 weeks were classified as B.1.617.2, or delta, a highly contagious variant that was first detected in India and is now the dominant strain in the U.S.

De Blasio said the city was watching the data carefully, and the low hospitalization rate was a good sign. On average, about 20 patients have been hospitalized daily citywide, some of the lowest rates since the beginning of the pandemic.

Nationally, the U.S. is reporting a seven-day case rate of about 37 cases per 100,000 people, with New York City at about 21. Missouri and Arkansas have the highest rates, at more than 160 per 100,000.