Although Mayor Eric Adams has lifted COVID-19 restrictions in recent weeks due to low overall case counts, some New Yorkers may still be in the habit of keeping an eye on how the coronavirus is trending, the way one might routinely check the weather.

Anyone looking at the city’s COVID-19 data in the last two weeks might have noticed something curious: The number of cases started creeping up again just as the positivity rate was trending down. Now, the rate is stable as cases continue to rise. During past surges, the two metrics have tended to follow each other.

Gothamist reached out to a pair of infectious disease experts to understand why this might be happening — and whether the slight uptick in cases is cause for concern. The New York City Health Department also explained the potential impact of Congress withholding pandemic funds. The agency said city-run testing sites should remain free and available to all but worried that some private sites might start turning away those who are uninsured.

Positivity versus cases

The positivity rate by itself is “an imperfect marker of what’s going on,” said Dr. Jeffrey Shaman, a professor in the department of environmental health sciences at Columbia University’s Mailman School of Public Health.

Shaman speculated that the positivity rate might be skewed by people who have allergies or are catching other illnesses with symptoms that are similar to the coronavirus and want to get tested to rule it out.

“The flu is going around now as well, and there are also lots of other bugs that are going around,” Shaman said. “Kids are taking their masks off at school and as a consequence of that, the germs that were being slowed in their transmission may have picked up their pace.”

His theory was shared by Dr. Anna Bershteyn, an assistant professor in the department of population health at the NYU Grossman School of Medicine.

“If we see that this little uptick in the number of cases is sustained over time, we should expect that the positivity rate will eventually come up, too,” she said.

Positivity rates are rising in some portions of New York City, namely ones that are also seeing higher demand for tests in recent days, such as Tribeca and other neighborhoods in Lower Manhattan.

The city has created a color-coded alert system, following the lead of the Centers for Disease Control and Prevention. Every Thursday evening, it relies on a mixture of case rates per 100,000 residents, hospital admissions and hospital capacity to judge risk levels in each borough. For Manhattan to move from its current level of low risk to medium risk, it would need to record about 3,200 cases total from one Thursday to the next. This week, it recorded 2,300 cases.

Preparing for the next wave?

Both Bershteyn and Shaman said it was too soon to tell whether the BA.2 subvariant of omicron that now dominates in New York would cause a significant surge in cases the way it has in parts of Europe. Nations like Scotland experienced dual surges in cases, hospitalizations and deaths this winter due to BA.2 thriving so soon after its sister.

Only 36% of New York City residents have received a booster shot, the strongest barrier against severe COVID-19. And about one in five residents caught the initial BA.1 omicron strain this winter, according to estimates from Bershteyn and her colleagues.

If all those people were separate individuals, then it would mean about half the city could have solid protection against BA.2. However, there is some overlap between those two groups, given the vaccines don't prevent infection with omicron. So, the population still vulnerable to BA.2 is likely larger.

But Bershteyn said it’s possible that vaccination plus temporary immunity from recent infections could be enough to protect New York City from being hit hard by BA.2. Vaccinated people, for example, are less likely to spread BA.2 onward to others, according to research from Denmark.

“It may not lead to a sustained climb,” she said. “I think that's yet to be seen.”

She predicted that parts of the country that were less impacted by the initial omicron surge might be hit harder by BA.2. Within New York City, Bershteyn said, “it's possible but not as clear whether there were pockets that were spared from BA.1.”

Over the past week, the average number of daily cases in New York City has crept above 1,100, according to data recorded by the Centers for Disease Control and Prevention. That’s about 40% higher than a low point — 646 cases per day — recorded in early March, but a vast improvement over the more than 40,000 daily cases seen at the peak of the omicron surge in January.

“Over the past week, we've seen a small increase in reported COVID-19 cases in New York state and New York City, and some increases in people in the hospital with COVID-19 in New England,” CDC Director Dr. Rochelle Walensky said Wednesday during a White House briefing.

New York City health officials maintain that BA.2 is not currently a threat.

The new normal fundamentally is going to be about relaxing in-between waves when we can, and then tightening restrictions when waves come back.

Anna Bershteyn, NYU Grossman School of Medicine

“BA.2 has been increasing over the past several weeks, but at the same time, overall case numbers have been relatively stable with some increase in the last few days,” Dr. Celia Quinn, deputy commissioner of the city health department’s Division of Disease Control, said during a press conference on COVID-19 on March 18. The same pattern happened with BA.2 in the United Kingdom before it was hit with a second surge of cases and hospitalizations.

She added that BA.2 does not appear to cause more severe illness than other strains of omicron but does appear to be more transmissible. Health officials have said it’s anywhere from 30% to 60% more infectious.

There have been plenty of anecdotal reports of people getting COVID-19 in recent days, but it’s likely that not all of those cases are being recorded. As rapid at-home tests become prevalent, city officials have maintained that there are still enough people getting tested at city-run sites and private clinics to provide early warning signs of a new wave. At the March 18 press conference, the city noted that test results for about 60,000 people had been reported on a recent day.

Shaman said there are formulas for determining how many tests are enough for a given population but said that his gut reaction was, “That should be ample to detect signals of what's going on, so long as it's not heavily biased to exclude certain populations.” Since last week, the daily average of PCR and antigen tests at clinics has fallen to 54,000. Testing volume varies day to day but has been trending downward since early March. The city does not allow most New Yorkers to report their at-home test results for official recordkeeping.

Free testing might end for private sites

It’s possible that federal changes to funding for COVID-19 tests could also impact access moving forward. The federal government is slated to stop covering COVID-19 tests for people who are uninsured on Friday.

Kate Smart, a spokesperson for the mayor's office, assured Gothamist that “city-run COVID-19 services will continue for all New Yorkers, regardless of insurance status.”

But she also expressed concern about the change, which could lead to private testing sites turning away or charging people who are uninsured. “The cuts to provider reimbursements for COVID-19 testing, vaccinations and treatments for uninsured and underinsured New Yorkers may have severe impacts on our city if not backstopped,” Smart said. “We fully support the work of our partners in Congress fighting to renew this critical funding.”

Regardless of what happens, Bershteyn said it’s expected that people will get tested less often at times when COVID-19 is less prevalent. Both she and Shaman also said it makes sense to loosen restrictions while there are fewer cases going around. Shaman said the key is for policymakers to be willing to tighten them again if necessary.

“I think the new normal fundamentally is going to be about relaxing in-between waves when we can, and then tightening restrictions when waves come back,” Bershteyn added.

When the time comes, she noted, it’s important to have sufficient warning to be able to act early. “I think the benefits of restrictions like masking and not having large indoor gatherings really happen on the leading end as the wave is rising,” she said.