Across D.C., Maryland and Virginia, more than 70% of adults are now partially or fully vaccinated against the coronavirus — meeting an ambitious goal set by the White House to have that percentage of American adults partially vaccinated by the Fourth of July.

Maryland passed the benchmark before Memorial Day (the state is currently at 73%), and Virginia and D.C. did so this week.

The milestone underscores the scale and reach of the vaccine rollout; by comparison, D.C. officials estimate that about 35% of Washingtonians get a flu shot annually.

“We hear so much bad news. This is good news,” says Dr. Anne Monroe, a professor of epidemiology at the George Washington University’s Milken Institute School of Public Health. “It represents a massive effort…I think that just recognizing what it took to get to this benchmark is important, and recognizing what still lies ahead is also very important.”

While the state-level figures have surpassed the 70% mark, there is variation among the counties in the Northern Virginia and Maryland suburbs.

Fairfax County, the most populous jurisdiction in the region, has 73.3% of adults vaccinated, while Loudoun County has hit 75.6%. Alexandria, Arlington County and Prince William County are just shy of meeting the goal, with 64.4%, 68.2% and 67.5% of adults partially or fully vaccinated, respectively.

In Maryland, Montgomery County has far outstripped the rest of the region in vaccinating its adult population: 88.7% of adults have received at least one dose of the vaccine. Prince George’s County is nearing the 70% threshold, with 68% of adults at least partially vaccinated.

Nationally, the White House now says it expects to just miss making its vaccination goal before the Fourth of July, largely because of lagging vaccinations among people under 30.

In the D.C. region, the 70% figure isn’t tied to any restrictions easing — across the region, most capacity limits and social distancing requirements are already lifted — and the number is a political benchmark, not an epidemiological one.

“It doesn’t have some kind of magical power,” says Monroe. “It is a number. It’s a benchmark.”

Monroe says the 70% goal may have originally been tied to earlier estimates of vaccination rates needed to achieve herd immunity, which have been rendered outdated because of the highly transmissible nature of new variants of the disease.

The metric also does not take into account the entire population of the region who can get vaccinated: by focusing on adults, the benchmark omits the children ages 12 and up who are currently eligible for the Pfizer vaccine. In D.C., for example, 67.8% of residents 12 years and older have been fully or partially vaccinated.

“In the U.S. as a whole, adults 18 and up make up about 75 percent of the total population of the US,” Monroe points out. “So when you look at targets for herd immunity, you’re usually looking at an entire population.”

And while the local adult population overall is 70% fully or partially vaccinated, public health officials are still struggling to overcome persistent racial gaps in access to vaccines and concerns about them — leading to areas of the region with lower vaccination rates. In D.C.’s Ward 8, which is majority-Black, just 26% of residents 12 and up are fully vaccinated. The rate is double that in wealthier, whiter Wards 2 and 3.

And the racial gulf is more significant in certain age groups. Just 5% of children ages 12-15 in Ward 8 have received at least one dose of the coronavirus vaccine, compared to 67% in Ward 2.

“Now that the people who were eager and activated and were able to take time off and were able to get themselves to a vaccination site and trusted that the vaccine was something that was beneficial to them — now that all those people pretty much have cleared the hurdle of getting vaccinated, this real challenge remains,” Monroe says. “How do you improve access in a way that is meaningful to people?”

Local gaps in vaccination rates are particularly concerning in light of the arrival of new, even more transmissible strains of COVID-19. Experts expect the Delta variant, which is the most contagious version of the coronavirus yet and may cause more serious illness than other strains, to become predominant in the U.S. this week. Meanwhile, scientists are concerned that another emerging strain, the Gamma variant, may be somewhat better able to get around vaccine immunity.

Monroe says that people who are vaccinated in the D.C. region should feel good knowing that many of their neighbors are protected, and transmission of the virus has receded — but continue to follow some basic public health recommendations, like washing their hands and preferring to socialize outdoors when possible.

“I think people should feel like they can resume some of the activities that they might want to resume, but to continue to be thoughtful and do the best that they can to to follow some of these basic infection infection prevention precautions,” she says.