On April 6, President Joe Biden announced that all American adults would be eligible for a COVID-19 vaccine by April 19.

"That's the way to beat this," Biden said Tuesday, announcing he was advancing his deadline by two weeks. "Get the vaccination when you can."

In most U.S. states, that was a superfluous command. They were already planning to allow all residents ages 16 and up to receive vaccinations on or near that date. But not Oregon.

Gov. Kate Brown and health officials had doggedly stuck to their plan to roll out COVID-19 vaccinations gradually to people at risk of severe illness and workers in jobs that have a high risk of exposure. She did not intend to make all adults eligible for a first dose until May 1.

Hours after news broke that Biden would issue his directive, Brown announced she was complying. Her statement did not mention the president. Instead, she again stressed the importance of getting vaccines to Oregon's most vulnerable people.

"We must reach Oregonians where they are, including those who may not have easy access to health care or the ability to take time off from work," Brown said in her statement.

Only two other states were waiting beyond April 19.

Last week, Washington declared all residents eligible for a shot starting April 15. That's the date California already circled on the calendar. And Idaho? It made everyone eligible a week ago.

That made Oregon an island of enforced patience. Biden moving up the deadline throws into uncertainty Brown's carefully orchestrated vaccine queue—one that experts say the governor had arranged to compensate for head-scratching decisions earlier in the rollout.

You may have questions. Here are the answers to some queries that might occur to you in the brief time left to wait.

Why can't everyone in Oregon have a COVID-19 shot right now?

The simple answer? The state still has a shortage of vaccines.

Some math: There are 3.5 million Oregonians over the age of 16, of which 1.3 million have already gotten at least a first dose, according to Oregon Health Authority data. That leaves up to 2.2 million Oregonians competing for COVID-19 vaccine doses, if everyone became eligible right now.

This week, OHA says it's receiving a record number of prime doses: 275,000.

See the mismatch? That's eight Oregonians who might want a vaccine for every one dose available this week.

For the next several weeks, the state is expecting far fewer doses—only 150,000 a week—because Johnson & Johnson had a manufacturing problem that will delay doses nationwide.

In other words, making everyone eligible for a vaccine isn't the same thing as giving everyone a vaccine.

"If we were just to open it up to everyone, people would still have to wait in line," says Oregon State University professor Courtney Campbell, a bioethicist.

Then why were other states opening up eligibility to everybody?

Some states have less of a mismatch between supply and demand. Take Idaho, which cited a lack of demand as it failed to vaccinate very many people: Its COVID vaccination rate is eighth lowest in the nation.

Other states say they are moving fast because they have plenty of vaccines.

California Gov. Gavin Newsom cited "abundance" on March 25 as the reason he was expanding eligibility so quickly—at least before the Johnson & Johnson delays.

Washington also cited plenty of vaccines. "Thanks to increasing vaccine supply from the federal government and hard work from our providers across the state to get shots in arms, we are able to expand eligibility sooner than anyone initially thought," said Washington Secretary of Health Dr. Umair A. Shah in a statement March 31.

But those states don't have enough supply to vaccinate every eligible person, either. In some cases, they might have more doses than Oregon—OHA has complained it is receiving less than its fair share—but not so many that they can match the expected surge of demand once everyone is eligible.

In other words, more people aren't getting a vaccine in California. Instead, different people might be getting it.

What was Oregon doing differently?

Gov. Brown has cited a commitment to equity as her reason for keeping eligibility comparatively narrow. She says she wants to make sure the communities most impacted by COVID-19 get first access to the vaccines.

"Right now, we are focused on ensuring those populations have the opportunity to receive their vaccine before opening up to every Oregonian 16 and up," Brown spokesman Charles Boyle told WW on March 29. "Oregon's prioritization schedule is designed to ensure equity in distribution when vaccine supplies are scarce."

Oregon has a mixed track record so far on equitably distributing the vaccine.

As of March 29, an analysis by Kaiser Family Foundation showed only a 2 percentage point difference between Black and white Oregonians for vaccinations. That's the second-smallest racial gap in the country.

But the state has a 15-point gap between white and Hispanic Oregonians, which is worse than average for the country, and places Oregon 20th out of the 30 states reporting demographic data.

Perhaps that's because Oregon has been slower to make frontline workers and people with high-risk medical conditions eligible for the shots than other states, just as the state was slower in making older Oregonians eligible. Both Washington and California opened up eligibility to these groups earlier and have a lower gap between their Hispanic and white vaccination rates.

Brown, announcing the shift to April 19, cited her ongoing commitment to equity.

"Over the next two weeks, we will dedicate all available resources to ensure Oregon's frontline workers and people with underlying conditions have access to vaccines––two groups in which Oregonians from communities of color are predominantly represented."

Who's right—Biden or Brown?

Oregon has fallen behind in its vaccination rate, from 16th in the nation to 32nd. Clearly, speed matters if the goal is to prevent deaths. So there's a case for going as fast as possible—which means eliminating all barriers.

But some critics of the governor's previous decisions on vaccine eligibility say the groups currently being made eligible are critical to reach.

The state had the chance to address some of the unfairness of its previous decisions—like vaccinating teachers early on and giving shots to grocery workers much later, Oregon experts said. Making everyone eligible now would create a crush of demand and squeeze out frontline workers who waited through February and March.

"If you open it up right now to everyone, some individuals have greater access in terms of transportation, proximity to vaccine clinics, proximity to information," says OSU's Campbell. Allowing that to happen, he adds, would worsen "the misuse of an especially scarce resource in late January and early February."

In other words, Oregon was stuck with its ordering system because it gave short shrift to some vulnerable people earlier in the vaccine rollout.

Multiple experts point out that eligibility isn't the only answer to ensure equity. Some states are reserving vaccines for certain underserved groups even as they open up vaccinations to everyone. And more outreach is required from Oregon public health agencies whose weakness has already been exposed by other parts of the pandemic.

"There are so many other factors that come into play," says Nambi Ndugga, a policy analyst with Kaiser Family Foundation's Racial Equity and Health Policy Program. "Accessibility, working times, being able to sign up for the vaccination are examples. Addressing these other barriers to equity will impact how equitable the vaccine is."

Even before Biden's announcement, Brown said she felt an urgency to get shots into arms.

"Make no mistake, this is a race between the vaccines and the variants," she said April 2. "It is a critical moment for us all to double down so we can outrun this next wave."

Correction: Due to an editor's error, this story incorrectly stated that Gov. Brown announced a changed vaccine timeline after President Biden issued his directive. In fact, she made her announcement after news broke of the president's directive but before Biden made his speech. The governor's office says Brown made her decision after consulting with the White House on April 5. WW regrets the error.