By Stephanie Stahl

PHILADELPHIA (CBS) — A dramatic drop in the number of Americans getting COVID-19 booster shots has doctors issuing urgent pleas for people to get the extra dose of protection. There’s also confusion about certain high-risk groups and when they should get vaccinations.

People who are immunocompromised need to get four shots of vaccine, but apparently, that’s not understood by some drug stores who received a warning from the U.S. Centers for Disease Control and Prevention. Even if you’re not high risk, boosters are still recommended, but they’re not being received by a growing number of Americans.

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Booster shots prevent severe disease and hospitalizations, but there’s been a sharp decline of 55% in the last month in the number of people getting that extra shot of protection.

“Convincing people that they need that additional dose is a little bit of a heavy lift,” Health Commissioner Dr. Cheryl Bettigole said.

Nationally, just 40% of those eligible have received booster shots. In Pennsylvania, the rate is only 23% of residents getting boosters, 32% in New Jersey, and Delaware is at 33%. In Philadelphia, where 37% of residents have received booster shots, rates are especially low in minority communities.

“It’s been a little bit challenging. One of the challenges people describe is being worried about side effects, for example,” Bettigole said.

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But side effects from booters are similar to the first shots. There can be temporary flu-like symptoms.

“I wish booster rates were a little bit better,” said Dr. Timothy Friel, chair of medicine at Lehigh Valley Health Network. “We need to focus our attention on those who are going to benefit the most from boosters.”

Friel says boosters can be lifesavers for high-risk groups.

For people who are immunocompromised, it’s recommended they get four doses of vaccine, but that’s been hard to find for some, prompting a warning to providers from the CDC.

“I think there was a little bit of confusion,” Friel said. “Now, what we are recommending is five months after that third dose that individuals come back for their official booster. So, for immunocompromised individuals, it’s actually their fourth dose.”

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Doctors say boosters are critical for high-risk groups because COVID-19 can be especially dangerous for them.

Stephanie Stahl