Will You Need An Extra COVID-19 Booster Shot?

CHICAGO (CBS) --  Will you need a fourth dose of the COVID-19 vaccine?

We're learning when that extra booster could be rolled out. CBS 2's Meredith Barack reports on new information on the timeline.

A Food and Drug Administration (FDA) official is suggesting a fourth dose of the COVID-19 vaccine might be needed closer to the fall. But administering a fourth dose will be dependent on data, emerging variants and trials happening right now.

"What they were finding was after the span of about four months, immunity did drop. So suggesting that especially for high risk people, there may be a fourth dose coming down the line."

Dr. Elizabeth Van Opstal works in internal medicine and pediatrics at Rush Medical Center. She is referring to the findings released by a study from the CDC last week, looking at patients who had two or three doses of the COVID vaccine.

How soon could we see that fourth shot, or additional booster, being put into arms?

"Some sources said it could be the fall, but I think things have been somewhat unpredictable," said Van Opstal.

Currently, a fourth shot is only recommended for people who are immunocompromised. Van Opstal said as we know, we are dealing with an ever changing virus and should we see new strands, we could need the fourth dose sooner.

But for now, we can likely anticipate it will be administered starting this fall, which would give people that extra boost of immunity heading into winter, when COVID cases historically have risen.

"It does seem in general, at least over the last two years, that the summer has been less COVID transmission. More people are outside," Van Opstal said.

The current number of hospitalizations and positive cases looks promising.

"The last week and a half, I work on COVID units, I work in the hospital. I haven't seen any cases of COVID and so that's incredible encouraging," said Van Opstal.

But Dr. Van Opstal said that doesn't mean we can let our guard down yet, especially those who are immunocompromised.

"We're all hoping that this will stay down, the rates will stay down. but I think it's a little unpredictable and we have to follow the science, follow what happens with new strands or hopefully we won't see as much and that would be amazing," Van Opstal said.

Israel is one country already administering a fourth dose. and Sweden is now recommending a second booster for everyone 80 or older.