The Food and Drug Administration on Thursday approved a third, updated version of Pfizer and Moderna’s COVID-19 vaccine, which could be made available to the public in the coming days.

Here’s what you need to know.

What is different about this vaccine? Why should I get it?

According to the FDA, the latest formula targets what is expected to be the dominant strain of the virus, similar to how it treats the flu.

While the latest variant follows the virus’s pattern of becoming more contagious but less deadly, the virus is still killing about 600 people a week in the U.S., said Dr. Beverly Sha, an infectious disease physician at Rush University Medical Center.

Sha, who worked on previous clinical trials for COVID-19 vaccines, said immunity wanes after six months, despite earlier expectations it would last longer.

“When the vaccines first became available, we hoped that the immunity would be robust and long-lasting, but that has not been the case,” Sha told the Sun-Times on Friday. “Like with the flu, every fall they come out with a new version of the vaccine for what is expected to be circulating in the winter months.”

Pharmaceutical companies only need to change the COVID-19 variant that the vaccine targets. That means they can develop vaccines faster, because there is a lot of transmission between different vaccine versions.

“Everything about the vaccines is the same, so the safety data that we have collected still applies,” Sha said. “I’m not advocating for anything that I wouldn’t do for myself or my family.”

Who can get it?

Unvaccinated children between 6 months and 4 years old can get three doses of the new Pfizer vaccine or two doses of the new Moderna vaccine, the FDA said. Children of the same age who have previously been vaccinated against COVID-19 can get one or two doses of each, while children ages 5 to 11 can get a single dose.

According to the FDA, people who are at least 12 years old can receive a single dose of the new Comirnaty or Spikevax vaccine.

For everyone aged 5 years or older, the new vaccination must be given at least two months after the previous vaccination.

Dr. Sindhu Aderson, medical director of the central region for Northwestern Medicine Immediate Care, compared it to an annual flu shot and suggested people get both their flu shot and their COVID-19 shot as a precaution. She noted that it’s important for people with weakened immune systems or other complications, such as heart or lung disease, to keep their vaccinations up to date.

“We want to make sure that we keep the general population safe,” Aderson said. “(But) it’s really important for people who are at high risk for severe COVID infection, they should really seek out these updated boosters.”

Where and when can I get it?

CVS and Walgreens are accepting appointments prior to the vaccine’s release. CVS will offer vaccinations for walk-in or scheduled appointments in the coming days. Walgreens has said the new vaccine will be available beginning Sept. 6.

Aderson said the new vaccines will be available at urgent care clinics sometime in the next month, but they have not yet received specific dates.

The Chicago Department of Public Health is advising people to check with their health care providers for when vaccines will be available and said it will share information about how to access the vaccines without insurance “as soon as they become available.”

Do I have to pay for this?

While the CDC’s Bridge Access Program — which provided free COVID-19 vaccines to uninsured and underinsured adults — has ended, preventive care is typically covered by insurance, Aderson said. She said patients should contact providers and insurance companies ahead of time to find out what the cost will be to them.

Charlie Rice-Minoso, a spokesperson for CVS, said some systems may not be updated right away, resulting in an initial out-of-pocket cost of $201.99 before it is reimbursed by their insurance company. Patients can choose to come back later once things are sorted out.

Where are we now with COVID-19?

Aderson said COVID-19 levels are “higher than we’re used to seeing this time of year” due to increased gatherings and travel over the summer. So far, COVID-19 has outpaced the flu, though she noted it’s still early in the season.

While the city is no longer reporting COVID-19 data as it once did, the most recent city data, which is from the week of August 4-10, puts the COVID-19 test positivity rate at 15.2%, or about 110 people who tested positive out of 719 who tested. This is lower than the recently reported national average of about 18%.

The CDC is also reporting an increase in cases and hospitalizations.

However, these numbers are probably underestimated.

“People may have very mild symptoms and may not even need to be tested,” Aderson said. “(And) those who do have symptoms may do home testing and just isolate themselves at home.”