President Joe Biden announced a new pandemic action plan on Thursday, which addressed new vaccine mandates, booster shots, expanded COVID-19 testing and the economic recovery. Saying, «We’ve been patient, but our patience is wearing thin,» Biden underlined concerns around coronavirus breakthrough cases among the fully vaccinated, especially in areas with low vaccination rates.

As a component of the multistep «Path Out of the Pandemic» plan, the White House reiterated its recommendation for vaccine boosters to stay ahead of the virus. While Biden said there are enough boosters to be administered by the original late September projection, the details surrounding who can get them — and when — are pending authorization by the Food and Drug Administration and the Centers for Disease Control and Prevention.

The push for boosters is based on research showing how the effectiveness of the vaccines can decline over time. An additional shot provides enhanced protection against the surging COVID-19 delta variant. In his remarks this week, Biden pointed out that the risk of severe illness from a breakthrough case is still minimal: There’s only one confirmed positive case per day among every 5,000 people who’ve been fully inoculated.

Read on for what we know about COVID-19 booster shots today, including who can get them now and why they’re needed. We’ll also explain how they relate to breakthrough infections and what the controversy has been surrounding the shots. We’ve updated this story recently.

When will COVID booster shots be made available to all?

On Thursday, Biden didn’t give a specific date for the first round of booster shots. Instead, he said they would be available once they’re approved. «As soon as they are authorized, those eligible will be able to get a booster right away, in ten of thousands of sites across the country … and for free,» Biden said.

The latest White House statement says the administration is prepared to offer boosters as early as Sept. 20, which was the date laid out in the initial August booster recommendation. On Sept. 3, the New York Times reported that the FDA and the CDC were advising the White House to scale back its timeline.

While the original booster recommendation applied to the Pfizer-BioNTech and Moderna vaccines, government officialshave recently cautioned that boosters may first be available for thosewho received the Pfizer vaccine, because regulators may need more timeto evaluate the other vaccines. On Sept. 5,Chief Medical Adviser Anthony Fauci confirmed that the rollout forModerna’s vaccine booster could come later than Pfizer’s.

Why are booster shots even necessary?

«Recent data makes clear that protection against mild and moderate disease has decreased over time,» US Surgeon General Vivek Murthy said during an August briefing on COVID-19 vaccines. «This is likely due to both waning immunity and the strength of the widespread delta variant.»

Calling the eradication of the COVID-19 virus «unlikely,» a UK scientific advisory group found (PDF) a «realistic possibility» that a variant will emerge that is resistant to the current battery of vaccines. Governments, public health organizations and vaccine makers are all tracking developments in coronavirus variants like delta and lambda, hoping to determine if booster shots targeting new variants will be needed among the general population.

Why is a Pfizer vaccine booster likely to be available first?

According to a report by the New York Times onSept. 3, administration health officials warn that the scientists of the FDA and CDC maynot have enough time to approve boosters from all vaccine manufacturersin time to meet Biden’s goal of starting booster shots on Sept. 20.

«We were hoping that we would get bothproducts, Moderna and Pfizer, rolled out by the week of the 20th,» Fauci said on Sept. 5. «It isconceivable that we will only have one of them out, but the other willlikely follow soon thereafter.»

Who would be eligible to get a vaccine booster shot?

In August, health officials in the Biden administration recommended an additional shot for Americans 18 and over who are fully vaccinated with the Pfizer or Moderna shots, proposing a booster eight months after being fully vaccinated.

Waiting months in between doses allows the immune system to develop a full response before it is helped by a boost. Whatever the time gap, the booster plan would need to be evaluated and approved by government scientists.

«We believe that that third dose will ultimately be needed to provide the fullest and continual extent of protection that we think people need from the virus,» Murthy said. «Our plan is to stay ahead of this virus by being prepared to offer COVID-19 booster shots to fully vaccinated adults 18 years and older.»

Murthy said the FDA will evaluate booster shots for those younger than 18 years of age, and the administration will follow FDA recommendations for minors.

How does FDA approval of Pfizer’s vaccine impact boosters?

On Aug. 23, the FDA approved Pfizer’s COVID-19 vaccine for two doses for people 16 and older. The Pfizer vaccine is the first to receive FDA approval, while Moderna and Johnson & Johnson vaccines are available under an emergency use authorization. And for children ages 12 to 15, Pfizer’s vaccine is authorized for emergency use.

While a third dose for some immunocompromised individuals is authorized for emergency use, the FDA final authorization does not include a booster shot.

Some health care experts believe the two-shot approval could give a push to those who were waiting on the FDA before getting vaccinated. The approval could also lead to more businesses, schools and venues mandating vaccine requirements.

What about a Johnson & Johnson booster?

On Aug. 25, Johnson & Johnson saida booster shot of its COVID-19 vaccine increases antibody responses inthose who received the company’s one-dose vaccine, based on interimdatafrom anearly trial. Biden administration health officials said they expect those who received the one-dose Johnson & Johnson vaccine will need another jab, but more research is necessary.

The company said it would work with public healthofficials on a plan for a booster shot for eightmonths or longerafter the first dose of its vaccine, but there is no time frame in place. Currently,the one-doseJohnson & Johnson vaccine is available under anemergency useauthorization for individuals 18 years of age and older.

Who is eligible for booster shots now?

Some immunocompromised people who already are eligible under guidelines from the CDC can go out and get their third dose of a COVID-19 vaccine immediately. The list of people who are eligible now includes solid-organ transplant recipients and people who have an «equivalent level of immunocompromise» and who have a reduced ability to fight off infections, making them more vulnerable to the coronavirus.

Among those immunocompromised people, the booster recommendation is for those 18 and older for the Moderna vaccine, and 12 and older for the Pfizer vaccine. The FDA didn’t authorize an additional dose of the Johnson & Johnson vaccine, and because of a lack of data the CDC hasn’t recommended a second dose for immunocompromised people who got the one-shot vaccine.

About 3% of US adults are immunocompromised, according to the CDC, but research suggests they account for about 44% of hospitalized breakthrough cases of COVID-19. Not only are they more likely to get very ill from COVID-19, they also have a lower antibody response to vaccines and are at a higher risk of transmitting the virus.

Those with other conditions, like diabetes and heart disease, aren’t advised to get a booster, at least for now. Here’s a list of people the CDC recommends get an extra dose if they got the Pfizer or Moderna vaccine:

• Those with advanced or untreated HIV infection.
• Cancer patients and transplant recipients who are taking certain immunosuppressive drugs.
• Those receiving active cancer treatment for tumors or cancers of the blood.
• Those with moderate or severe primary immunodeficiency.
• Patients being treated with high-dose corticosteroids or other drugs that may suppress immune response.
• People who received a stem cell transplant within the last two years and are taking certain drugs. The CDC says to talk to your medical provider about your health condition and whether a third shot is appropriate.

If you’re unsure whether you’re qualified, the CDC says to talk to your medical provider about your health condition and whether a third dose is appropriate.

Will booster shots be free?

The current one-dose vaccine shot from Johnson & Johnson and two-dose vaccines from Moderna and Pfizer are free to anyone who wants to get vaccinated. And the additional shots will be free too.

«These booster shots are free,» Biden said. «It will be easy. Just show your vaccination card and you’ll get a booster. No other ID. No insurance. No state registry requirements.»

«It will be just as easy and convenient to get a booster shot as it is to get a first shot today. We have enough vaccine supply for every American,» said White House COVID-19 Response Coordinator Jeff Zients, adding that those who are eligible will be able to get a booster at roughly 80,000 places across the country, including over 40,000 local pharmacies. Zients said 90% of Americans have a vaccine site within 5 miles of where they live.

Vaccines.gov provides information, including what vaccines are available at each site and, for many sites, what appointments are open. A toll-free number, 1-800-232-0233, will also be available in over 150languages. Americans who have already utilized the text code 438829 orWhatsApp to get vaccine information will automatically receive a textwith information on boosters, if and when recommended.

What’s happening with COVID-19 breakthrough cases?

As of July, in the US, «breakthrough» coronavirus cases caused by the dominant delta variant amount to less than 1% of people who are fully vaccinated. Both the Moderna and Pfizer vaccines have proven to be more than 90% effective against hospitalizations and death. Nonetheless, a CDC study shows that vaccinated people can both contract the highly contagious delta variant and spread it. According to a widely reported internal CDC memo, the delta variant spreads as easily as chicken pox, which is considered more contagious than the flu but less contagious than measles.

The surge in new COVID-19 cases is primarily affecting unvaccinated people and causing community spread, and in turn, prompting the return of mask mandates and guidance in hard-hit areas, even for people who have full vaccine protection. The debate over mask use and vaccine boosters underscores how scientists and other health experts continue to grapple with the uncertainties of COVID-19.

What’s the controversy with the WHO over booster shots?

The plan for boosters has resulted in a backlash among countries that are struggling to deliver first and second shots to residents.

Last month, World Health Organization Director-General Tedros Adhanom Ghebreyesus called for a «moratorium» on booster shots in high-income countries, citing the global disparity in vaccine distribution. Of the 4 billion doses administered globally, 80% have gone to high- and upper-middle income countries that make up less than half the world’s population, he said. He also called on vaccine producers to prioritize Covax, the world’s COVID-19 vaccine distribution program.

At a Sept. 8 news conference, Tedros said that the world’s poor shouldn’t have to be satisfied with leftovers. «Because manufacturers have prioritized or been legally obliged to fulfill bilateral deals with rich countries willing to pay top dollar, low-income countries have been deprived of the tools to protect their people,» he said.

White House Press Secretary Jen Psaki said on Aug. 17 that the US will have enough vaccines to both provide boosters for those who are fully vaccinated in the US and meet the global demand. «We have long planned from enough supply,» she said.

The US has so far shipped 115 million vaccine doses to 80 different countries, Zients said. «Our wartime efforts will continue doing everything we can to get even more people vaccinated both here at home and around the world. We can and must do both at the same time because that’s what it’s going to take to end this pandemic,» he said.

Is it okay to mix and match COVID-19 vaccines?

According to the New York Times, administration officials will recommend people get a booster of the same vaccine they originally received. On Sunday, Fauci said the White House will soon release data on mixing vaccines from different manufacturers.

While we watch how the situation develops, here’s what we know about the delta variant and info on whether you should continue to wear a mask.

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.