LONDON, ONT. -- COVID-19 vaccine supply remains tight in London and Middlesex County a day after 135,000 people 18 to 39 years old became eligible to book appointments.

Dr. Chris Mackie says the province’s decision not to allocate additional vaccine to the region comes as his capacity to administer shots is double the supply received each week by the Middlesex-London Health Unit (MLHU).

“We made a strong case, the capacity is here, we still have about twice as much capacity as we have vaccine coming in here,” says Dr. Mackie.

On Tuesday, Solicitor General of Ontario Sylvia Jones told CTV News the province has an additional strategic supply.

“Show us your plans for how quickly you can vaccinate people, how your inventory can literally be provided as quickly as possible, and we have some provincial strategic supply,” Jones explained.

Five weeks out, pressure is mounting to ensure everyone has a ‘one-dose summer’.

“If a lot more people are coming forward for appointments, and we don’t have additional vaccine allocated, then we’re going to have a problem,” adds Dr. Mackie.

Meanwhile, a significant amount of our region’s vaccine capacity in June will go towards 12 to 17 year olds when they become eligible to book appointments the week of May 31.

Mackie says, “That potentially displaces some of the adults who would have otherwise been vaccinated with that vaccine.”

Dr Mackie explains he took a calculated risk Tuesday, booking appointments for vaccine that wasn’t yet guaranteed to arrive.

It avoided disappointment, but balancing local supply with predicted demand is an ongoing challenge.

“It’s a tightrope, we are on a wire, there aren’t a lot of appointments left, but there are still some in the system, and each day we add more as we (look) weeks out.”