Connecticut's first mass vaccination site is now open to seniors 75 and over, by appointment only.

A site in East Hartford at the Pratt & Whitney aerospace complex held a soft launch Monday with roughly 500 planned vaccinations.

"We're at Pratt & Whitney Airport," said Mark Masselli, CEO of Community Health Center. "Hasn't been used in probably 35 years. In one week, we've set up a vaccination clinic -- a drive-thru one."

Those getting a vaccine drive up to a trailer and display a given QR code before getting the shot. They must also park for at least 15 minutes to look out for any possible adverse reactions.

Delores Arsenault of East Hartford said the process was "really easy, really smooth."

The lines are short, and the wait is just a few minutes.

The federal website to sign up, called VAMS, can be a bit confusing, according to vaccination seekers.

"The signing up was a little testy," said a woman from Vernon named Nancy. "I think everybody has said that."

Eventually the Pratt & Whitney site will vaccinate up to 10,000 people each week.

Appointments can also be made by calling the the CT COVID Vaccine Appointment Assist Line at 877-918-2224.