NEW YORK (AP) — Soaring COVID-19 case numbers, long testing lines, and event cancellations might feel a bit like déjà vu, but so far New York City hospitals aren’t seeing a repeat of the surges that swamped emergency rooms early in the pandemic. The state reported Saturday that nearly 22,000 people had tested positive for COVID on Friday—eclipsing the previous day’s mark for the highest single-day total for new cases since testing became widely available.

More than half of the positive results were in New York City. But new hospitalizations and deaths so far are averaging well below their spring 2020 peak and even compared to where they were this time last year. Still, Mayor Bill de Blasio described it as an urgent situation. “We are seeing a very substantial rise in the member of cases in a way we haven’t seen previously,” he said in a rare Sunday press conference.

The stark contrast in the number of hospitalizations within this latest wave of infections could be attributed to several factors, including New York City’s vaccination rates. As of Saturday, 82% of adult New Yorkers were fully vaccinated and 71.1% of the city’s entire eligible population, including children as young as 5 years old, were fully vaccinated.

“We can weather that storm if more and more people get vaccinated, more and more people go get those boosters,” de Blasio said. “This temporary reality demands an urgent immediate step, which is to maximize vaccination.”

Scientific research has shown that the COVID vaccines are effective in preventing hospitalization from the virus. The CDC reported that the Moderna vaccine is 93% effective, the Pfizer-BioNTech vaccine is 88% effective and the J&J vaccine is 71% effective.

Additionally, early analysis of the new omicron variant indicates that while it appears to be highly transmissible, and may more easily evade vaccine protection, it also may cause less severe disease, which would allow more people to self-resolve at home rather than be hospitalized with a potentially deadly case of COVID.

A new study out of Britain found the top five early symptoms related to the omicron variant were similar to a cold: runny nose, headache, fatigue, sneezing, and a sore throat.

However, Dr. Anthony Fauci warned Americans not to let their guard down, as the dangerous and deadly delta variant continues to pose a serious threat in the U.S. “We are in a situation where we are now facing a very important delta surge and we are looking over our shoulder at an oncoming omicron surge,” Fauci, chief medical adviser to President Joe Biden, said of the two COVID-19 variants.