With major jumps in the prices of some health plans and lower subsidies on others this year, the Massachusetts Health Connector is seeing more of its members switching plans and shopping around than in the past.

After 55,028 people facing a premium increase of 15 percent or more next year received messages from connector officials advising them of their options, 12,746 of them have actively shopped for a new plan through the insurance clearinghouse. That figure – 23 percent – is more than double the rate at which the broader population of members renewing their coverage shops around, connector staff said Thursday.

Consumers are in the midst of an open enrollment period during which they can buy their own insurance through the connector marketplace. Open enrollment closes in 54 days – Jan. 31 – but three weeks remain until a deadline to pay for January coverage.

Overall, unsubsidized plan premium costs are climbing 19 percent next year, connector officials have said. At the high end, Harvard Pilgrim Health Care will rise 47.1 percent and Neighborhood Health Plan 24.7 percent. Boston Medical Center HealthNet has the smallest increase, with premiums rising an average of 1.4 percent.

The connector is also restricting subsidies that lessen the cost of pricier plans within income brackets in subsidized ConnectorCare plans.

“As many members are experiencing premium changes, we are seeing the kind of activity we want to see,” executive director Louis Gutierrez told the Health Connector Authority Board. “Members in plans with high premium increases are switching more often than staying put when they shop, which tends to indicate that members are paying attention but also availing themselves of shopping options. We do want to see more of that activity.”

The connector has encouraged members to shop around before enrolling or letting their coverage automatically renew, sending robo-calls, emails and letters.

Around 234,000 people were enrolled in plans through the connector at the start of December, Gutierrez said. The connector now has 227,483 enrolled for coverage in January, and another 16,780 who have selected a plan through the website but not yet checked out.

Gutierrez said “quite a number” of members have not shopped, and some may be waiting until the Dec. 23 payment deadline for coverage that starts in January.

“So the next three weeks, we really have to see continued high-volume shopping activity,” he said.