J&J’s coronavirus shot could dramatically accelerate the US vaccine rollout. Here’s your new vaccination timeline.

• Johnson & Johnson’s single-dose coronavirus shot was just authorized for emergency use.
• With fresh vaccine doses from J&J, the US could finish vaccinating priority groups in March.
• The US could distribute 500 million doses by the end of June — enough to vaccinate all of its adult population.
• Visit the Business section of Insider for more stories.

A shot for every American. Political leaders and vaccine manufacturers have endeavored to meet this goal since the start of the pandemic, and it could finally become a reality this summer.

The vaccination campaign got a major boost on Saturday, when the US Food and Drug Administration greenlit Johnson & Johnson’s single-dose coronavirus shot. An FDA review published on Wednesday showed the shot is safe and effective against COVID-19.

J&J’s shot will be the third coronavirus vaccine to be distributed across the US. Vaccines from Pfizer and Moderna have been administered to more than 48 million Americans thus far, though fewer than 24 million Americans have gotten the full two-dose regimen. 

Pfizer and Moderna have pledged to distribute 600 million doses to the US public by the end of July – enough to fully vaccinate 300 million people. J&J, meanwhile, has said it could deliver up to 100 million doses of its vaccine by the end of June.

That means that by the summer, the US would have more than enough doses to vaccinate all 332 million-plus Americans (though shots haven’t been authorized for children under 16 yet).

Here’s a timeline of how vaccinations could ramp up in the next five months:

• March 31: 240 million doses distributed
• May 31: 420 million doses distributed
• June 30: 500 million doses distributed
• July 31: 700 million doses distributed

Pfizer’s and Moderna’s vaccines are each more than 90% effective at preventing symptomatic COVID-19, while J&J’s appears to be 66% effective at preventing moderate and severe cases. It’s difficult to compare the companies’ trials side-by-side, though, since they happened at different stages in the pandemic and in different geographic regions.

End of March: Wrapping up vaccinations for priority groups

J&J originally planned to deliver 12 million doses by the end of February. But federal officials have said that just 3 to 4 million doses would be immediately available next week.

By the end of March, the company will likely have produced 20 million doses, Richard Nettles, J&J’s vice president of US medical affairs, said at a House committee hearing on Tuesday.

Jeffrey Zients, the White House coronavirus czar, called the slow pace of J&J’s manufacturing “disappointing” on Wednesday. But the government has started helping the company procure equipment and raw materials, he said, which is accelerating the pace.

Pfizer and Moderna, meanwhile, are on track to distribute a cumulative 220 million doses by March 31.

At Tuesday’s hearing, Pfizer’s chief business officer, John Young, said the company intends to make 120 million doses available by the end of March (including the roughly 40 million doses shipped so far). Moderna’s president, Stephen Hoge, said the company would deliver 100 million doses (including 54 million that have gone out already) within the same time frame.

That means the US could finish vaccinating priority groups – including the elderly, essential workers, and people with high-risk medical conditions – next month. The Centers for Disease Control and Prevention estimates that these groups encompass roughly 200 million people.

End of May: The general population gets its shots 

In total, all three pharmaceutical companies are expected to deliver around 420 million doses by the end of May. Vaccinations for the general public could be in full swing by April.

Pfizer is on track to produce an additional 80 million doses by the end of May, bringing the company’s US total to 200 million. Moderna originally planned to deliver an additional 100 million doses in the US by the end of June, but now those should arrive in May.

Both companies are also still trying to speed up their vaccine rollouts.

Pfizer told USA TODAY it has added more production lines at its manufacturing plants, reduced the amount of time it takes to produce vaccine batches, and will soon cut down the time it takes to make DNA for the vaccines. In January, the FDA also instructed vaccinators to squeeze six doses from every vial of Pfizer’s vaccine, rather than the five that were initially authorized in December.

Hoge said Moderna is “working to enable up to 15 doses per vial in the near term,” instead of the 10 that vaccinators extract right now.

A recent report from the American Enterprise Institute, a right-leaning think tank, found that 50% of the US population could be protected from COVID-19 by mid-May if the J&J shot gets authorized. Without that third vaccine, it could take an additional two to three weeks to reach that point, the researchers said. 

End of June: All adults could have access to a shot

Nettles said J&J could deliver up to 100 million vaccine doses by June 30 (including the 20 million doses from the spring). That would bring the total coronavirus shots distributed in the US to 500 million – enough to vaccinate 300 million people, or all of the roughly 259 million adults in the US.

Federal officials still hope J&J can speed up that timeline.

“We’re working with the company to accelerate the pace and timeframe by which they deliver the full 100 million doses, which is required by contract by the end of June,” Zients said Wednesday. 

The American Enterprise Institute estimated that 75% of the US population could be protected from COVID-19 by mid- to late June, assuming that J&J’s shot gets authorized. 

End of July: The US could have a surplus of doses

By the end of July, the US could have more vaccines than it’s able to distribute.

Experts don’t expect the nation’s roughly 73 million children to start getting coronavirus shots until the fall or winter – or perhaps early 2022 – because there is not yet data about the vaccines’ safety or efficacy among younger age groups. (The exception is Pfizer’s shot, which is authorized for ages 16 and up.)

Both Pfizer and Moderna intend to deliver another 100 million doses each by the end of July, bringing the companies’ total doses to 300 million each. The US hasn’t purchased more than that, though it has the option to buy 200 million more doses each from J&J, Moderna, and Pfizer.

According to the American Enterprise Institute, “the addition of a third [vaccine] candidate will mean that anywhere from 22% to 33% more of the population can be vaccinated by July.”

This article was updated on February 27 with FDA’s decision to issue an emergency use authorization for J&J’s vaccine.