DENVER (KDVR) — Health experts are waiting for more information to determine how effective the COVID-19 vaccine is when it comes to stopping the spread of the virus.

According to the Centers for Disease Control and Prevention (CDC), a person who is vaccinated against COVID-19 can still be infected with or “carry” the virus that causes COVID-19 while not feeling sick or having symptoms. Experts call this “asymptomatic infection.”

The CDC says the vaccine is effective at keeping you from getting sick, but scientists are still learning how well it prevents people from spreading the virus.

“What we really need is more information and this information is more difficult to study than whether people get sick or not after getting vaccinated,” said Dr. Richard Zane, chief innovation officer with UCHealth.

Zane says there is emerging evidence indicating the vaccine does help prevent the spread of COVID-19, including studies out of Israel.

One study conducted by the Israeli Health Ministry and Pfizer Inc. found that the vaccine reduced infection, including asymptomatic cases, by 89.4% and in symptomatic cases by 93.7%.

Zane says a true indication of whether the vaccine helps prevent the spread of the virus will come from studying those who live or work with people who have been vaccinated.

“We need to compare them to those who are not close to someone who’s been vaccinated and then we also have to measure people who have been vaccinated and see if there is virus in their nose, essentially,” said Zane.

Zane says asymptomatic infection sets COVID-19 apart from other viruses, and makes it difficult to measure.