COVID-19 case counts in Pennsylvania and New Jersey remain low, but they’re moving, slowly, in the wrong direction.

Nationally gathered data that show slight case increases in both states in recent weeks, including in the Philadelphia suburbs, has health-care officials worried the more contagious delta variant could bring a new coronavirus surge to the still insufficiently vaccinated region.

“I’m still concerned, based on the number of people that are left unvaccinated, that we have a great enough number of vulnerable residents that it could be a real issue,” said Caryelle Lasher, assistant public health coordinator for Camden County.

The increase so far is a mild uptick, an increase of about a third in both states. Pennsylvania is averaging 228 cases a day, and New Jersey 312.

“It is unlikely that we will again approach the highs from last winter,” said Dawn Thomas, a spokesperson from the New Jersey Department of Health. “However, any time case counts are increasing it is a cause for concern and a reason to remain vigilant.”

The states’ counts look enviable compared with others now being swept by COVID-19. Florida, with a population less than double Pennsylvania’s, is averaging 24 times as many new daily cases, more than 5,500 a day. Missouri, with half as many people as Pennsylvania, has more than six times as many cases, averaging more than 1,500 new cases daily.

Case counts in local counties remain remarkably low compared with spring. In Montgomery County, for example, the county reported 1.6 new cases per 100,000 people as of July 13 compared with .9 at the beginning of the month. That’s an average of 13 cases a day. Bucks County is reporting 1.9 cases per 100,000, up from .7 on July 1, an average of about 12 cases per day.

Philadelphia’s case rates have remained virtually steady since the beginning of the month, according to an Inquirer data analysis.

“We know that there are delta cases in the city, and we’re seeing a slight rise in cases,” said James Garrow, a Philadelphia Department of Public Health spokesperson. “Given what delta has done to other places, we assume that the delta variant is circulating and infecting people.”

Hospitalizations are staying profoundly low. In Philadelphia’s Pennsylvania suburbs, home to 2.5 million people, 31 patients were hospitalized with COVID-19, according to an Inquirer analysis conducted Wednesday. Only two patients were on ventilators. In Philadelphia, just 46 people were hospitalized, a far different picture than the start of the year. On New Year’s Day nearly 1,600 people were hospitalized in the city and its suburbs, including more than 200 on ventilators and an additional 100 in intensive care units.

Those low numbers could change, though, if case counts keep rising.

» READ MORE: The delta variant isn’t dominant yet in the Philly region. More vaccinations could keep it that way.

Nationally, the delta variant appears to be playing a significant role in the case increases. It is unclear if the delta variant is more deadly than other strains of COVID-19, but it is easier to transmit, and it now accounts for more than half of all cases in the United States.

Bucks County Health Director David Damsker said new iterations of COVID-19 are no more surprising than the varieties of flu that emerge each year.

“We assume we will have delta cases going forward, at least until the next variant appears and takes over,” he said. “Every year the flu strains change as well, and we anticipate this will be similar in nature.”

Getting just one of a two-dose vaccine regimen is less protective against the delta variant than other strains, but for fully vaccinated people, the variant poses little risk, health officials have said. The full two-dose regimen of Pfizer-BioNTech vaccine has 88% efficacy against the variant, and federal officials have said protection from two doses of Moderna is likely similar. Johnson & Johnson has also reported its single-dose shot performs well against the delta variant. The new strain, though, threatens to sweep through unvaccinated populations.

That means a community’s ability to weather a delta-driven surge depends on its vaccination rates.

With about 49% of Montgomery County’s population fully vaccinated, for instance, “it is likely that this will help to keep the rate of increase in COVID infections that might be attributable to the delta variant under control,” said Richard Lorraine, chief medical officer for the Montgomery County Office of Public Health.

About 48% of Camden County’s population is vaccinated. The county is reporting an average of 10 new cases from July 6 to 12, she said, compared with seven a day from June 28 to July 5.

Right now, the county’s new cases appear scattered, Lasher said, often the result of one unvaccinated person bringing the virus home to a household of unvaccinated people. The delta variant, though, accounts for more than half the county’s cases now, and threatens to take hold in places like Camden City, where infection rates have remained somewhat higher than elsewhere in the county and vaccination rates are lower. Lasher plans to participate in a town hall on the delta variant for Camden County residents Thursday at noon.

“I do think there could be pockets of outbreaks based on those vaccine rates,” she said.

The county is performing contact tracing on all new cases, and said the majority of new cases, about 93% are among people who were either unvaccinated, not fully vaccinated, or the vaccination status could not be confirmed. Of the vaccinated people who tested positive, Lasher said, none became seriously ill.

The prevalence of the delta variant in the region is hard to quantify. Camden County estimated more than half of its new cases are the delta variant. In New Jersey, the variant represented about 40% of all cases in the last month. Pennsylvania officials said last week only about 3.9% of its past month’s cases were identified as the variant, but officials expect that number to rise.

» READ MORE: The delta variant is pushing COVID-19 cases up in some hotspots. Am I at risk if I’m vaccinated?

“We can project from nationwide and state numbers that there is likely to be an increase in the percentage of delta,” Lorraine said. “There has not been any significant increase in severity of illness and mortality even so.”

The risk of the delta variant, Damsker said, is minimal for vaccinated people and possibly not much more of a hazard to the unvaccinated than any other strain of COVID-19. Whether it’s the delta variant or some other version of COVID-19, he said, people who aren’t vaccinated are putting themselves in harm’s way.

He’s primarily concerned with a variant that proves resistant to the vaccines. Until that happens, there’s a simple way to avoid the virus.

“Whatever variant’s spreading now, there’ll be a different variant six months from now and then six months later. That’s just what viruses do,” Damsker said. “I don’t want people to get fixated on ‘delta variant, delta variant.’ We want people to get fixated on: Get vaccinated.”

Staff writers Justine McDaniel and Dylan Purcell contributed to this story.