ALLENTOWN, Pa. – The Centers for Disease Control and Prevention says the highly contagious Delta variant is now the dominant coronavirus strain in Americans.

It accounted for more than 51% of all new cases across the country as of July 3. That’s up from what it was a month ago, when it was just 3%.

It’s bad news for those who aren’t vaccinated. Health experts warn it’s more infectious and increases the risk of hospitalization.

But for people fully vaccinated, you’re in good shape.

“This virus will continue to mutate as long as it can infect people who are not fully vaccinated, so the more this virus continues to roll through populations the more chances it will have,” said Alex Benjamin, an infectious disease specialist at Lehigh Valley Health Network.

Local infectious disease specialists say the strain is still relatively rare in the Lehigh Valley. They’re investigating a possible case in Allentown.

But it’s popping up more in counties where the vaccination rate is lower than the average. That’s why the push for getting a shot is still a top priority.

“It is a wonderful reason everybody should get vaccinated. So those who have not been vaccinated yet or have not completed their two-dose series, we strongly encourage everyone to get their COVID-19 vaccines since the current COVID-19 vaccines do provide some protection against the variant,” said Belle Marks with the Allentown Health Bureau.

The CDC only recently upgraded its classification of the strain from “variant of interest” to “variant of concern.”

The Pennsylvania Department of Health responded to our request for comment with this statement:

“The Department of Health is taking the threat of COVID-19 and the variants like Delta very seriously. The best defense to contain the virus, prevent case surges and keep hospitalizations low, is for all eligible Pennsylvanians to get fully vaccinated.”

Nearly 48 percent of the U.S. is fully vaccinated.