ANNAPOLIS, MD (AP) – Maryland’s acting health secretary says the state will launch an online statewide system next month to pre-register for COVID-19 appointments at mass vaccination sites. Dennis Schrader told a panel of lawmakers the pre-registration system will enable the state to manage the flow of appointments. He says it also will be better prepared for when vaccine supplies are much more abundant. Lawmakers criticized Maryland’s vaccine rollout for not having a centralized way of registering for appointments. Maryland has two mass vaccination sites. One is at the Baltimore Convention Center. The other is at Six Flags American in Prince George’s County.