LOS ANGELES (CNS) — Los Angeles County has officially crossed the 4 million mark in total COVID-19 doses administered, but the public health director again warned Wednesday that getting an appointment for a shot will become more difficult starting Thursday when everyone aged 50 and over becomes eligible.

According to the Department of Public Health, a total of 4,013,521 doses have been administered in the county as of last Saturday. That includes 1,323,686 second doses, equating to the number of people who are now fully vaccinated.

"This does translate to tens of thousands of people having an extra layer of protection from serious illness and death due to COVID-19," Public Health Director Barbara Ferrer said. "While we still have a lot of work to do, I do hope we can all take a moment to be proud of what L.A. County has accomplished in really a little more than three months."

The county this week received its highest vaccine allocation to date, at 378,400, and that total does not include doses that were distributed directly by the federal government to some providers, such as pharmacies, health centers and the federally operated site at Cal State Los Angeles.

But despite that increase, the county still receives far short of the supply it has the capacity to administer, often leading to a shortage of appointments. That shortage will be exacerbated Thursday, when eligibility expands to all county residents aged 50 and over.

According to Ferrer, there are an estimated 2 million people in that age group in the county, although health officials estimate about 631,000 of them have already received at least one dose by qualifying in another eligible category. But that still means another 1.4 million people will be eligible and hunting for appointments.

"So we do ask both those currently eligible and those that will be newly eligible to be patient as supply increases," she said.

Things will get even worse on April 15, when everyone aged 16 and up becomes eligible for the shots. That group includes an estimated 5 million people, although about 1 million are believed to have already received at least one dose, Ferrer said. 

She stressed that the age-based categories of eligibility are reserved for county residents only. Categories of essential workers eligible for the shots were open to people who worked in the county, regardless of residence.

Ferrer expressed confidence that vaccine supplies will continue to improve, with the county projecting that a total of 700,000 doses per week will be dispatched to the county by the end of April.

"If L.A. County receives on average 576,000 doses a week, starting in April, we can expect to reach 80% vaccine coverage for people 16 and older in just 12 more weeks. Reaching such a milestone is possible with increased allocations, and it will dramatically change the trajectory of the pandemic here in L.A. County."

The county is already working to expand its ability to administer more doses, with the goal of being able to dole out 1 million doses per week.