At 9 a.m. Thursday morning, 1,800 vaccine appointments will open to senior citizens and health care workers in Wards 5, 7 and 8 in D.C. — an update from the earlier “priority zip codes” identified by the city, which included residents in wards 1 and 4.

On Friday at, an additional 1,800 appointments will open for residents ages 65 and older or healthcare workers living in any ward.

D.C. Mayor Muriel Bowser announced the change on Twitter Wednesday afternoon.

The focus on certain zip codes began last month, after the initial vaccination rollout to residents ages 65 and older showed gaping geographic and racial disparities. Residents in majority-white Ward 3, home to some of the city’s wealthiest neighborhoods, snagged the most spots of any ward in the first week of availability, at 2,465 appointments. Meanwhile, residents in majority-Black wards 7 and 8 secured 197 and 94 vaccine appointments, respectively. In an attempt to correct the inequity, the city moved to open more than 4,000 appointments to residents in wards 1, 4, 5, 7, and 8.

According to Bowser’s statement Wednesday, zip codes in wards 5, 7, and 8 were prioritized this week because they have the lowest percentage of residents 65 and older who have received a first dose of the vaccine. As of Jan. 28, only 11.3% of older residents in Ward 8 have received the vaccine, compared to 33.3% in Ward 3. Wards 5, 7, and 8 are also the wards with the highest number of residents who have died from COVID-19, according to D.C. Health data.

During a D.C. Council oversight hearing Monday, officials said the priority zip codes may change week-to-week, based on available data. 

Since the city opened its online portal for vaccine booking, appointments have been filling up quickly, often within 15 minutes of opening. Many residents have reported trouble accessing the online system, and last week D.C. Health quadrupled its number of call-takers to assist residents looking to book appointments over the phone.

As of Monday, the city has administered 62,219 doses of the vaccine, but D.C. Health is lacking race and ethnicity data for hundreds of thousands of vaccinated residents. D.C. Health has acknowledged the racial and geographic gaps in vaccine distribution, but officials maintain that supply continues to be the biggest constraint on the city’s vaccine rollout. Last week, the Biden administration announced it would be increasing D.C.’s federal allotment of doses by 15% for the next three weeks.