(NEXSTAR) – COVID cases are still on the rise, but an updated vaccine could be more than a month away. That leaves some concerned people in a predicament: get boosted now, or wait?

As of August, the latest version of the vaccine we have available is the “bivalent” shot, which was released last year. It was designed to target the highly contagious omicron variant of COVID, which is still the dominant variant to this day. However, studies show the bivalent shot’s effectiveness wanes substantially over time.

And over the past year, omicron has spawned many subtypes, each with a name composed of letters and numbers. The most common over much of the past year have been the XBB strains.

The new booster, which should be available by end of September or early October, is a monovalent vaccine, specifically made to target XBB.

Whether they want the protection now or not, many people have to wait for the XBB-targeting booster to be released because they’re not eligible for another dose now. If you’ve already gotten a bivalent shot, you may not be able to get a second dose.

Currently, the CDC only recommends a second bivalent shot for people who are immunocompromised or 65 and older.

“The vast majority of people can wait until the updated COVID shots are available in late September or early October,” said Dr. Peter Chin-Hong, an infectious disease expert at the University of California, San Francisco. “Given the increase in cases currently however, those who are 65 or older or those who are immunocompromised can chat with their health provider to determine whether they should get a dose of the currently available vaccines.”

Those groups shouldn’t worry they’ll be left behind when the new booster comes out this fall, Chin-Hong said. “These individuals will still be eligible to get the new COVID vaccine – even if an additional shot is received now,” he said.

Those who can get a booster now, shouldn’t wait, agreed Dr. Sherif Mossad, MD, infectious disease specialist at Cleveland Clinic, “since we don’t know when the new monovalent will become available.”

For those who haven’t gotten a bivalent dose yet, there’s still time. The CDC recommends one dose of the booster for everyone ages 6 and older.

Over the next few weeks, the Food and Drug Administration is expected to give more information on who can get the new booster shot and when. The CDC will provide its recommendations afterward, according to Dr. Anand Parekh, chief medical advisor at the Bipartisan Policy Center.

Not sure if you’re up to date on COVID-19 vaccines? The CDC has more information on its website.