MIDDLESEX CENTRE, ONT. -- The first inoculation in London, Ont. using the Pfizer bioNTech COVID-19 vaccine will happen on Wednesday, health officials say.

The London Health Sciences Centre (LHSC) and the Middlesex-London Health Unit announced the start of the vaccine program Tuesday, a day after the first doses reportedly arrived in the Forest City.

The first inoculations are expected to be administered to health-care staff in long-term care homes and other congregate settings that either care for seniors or are in outbreak.

The vaccinations will happen at the Western Fair Agriplex, where a temporary field hospital had been set up for the pandemic.

Vaccine rollout in Ontario began early last week, with new locations, including LHSC, added on Friday.

However, health officials have said the the vaccine is likely to be in short supply in early days, and it's unclear when the vaccine will be available beyond health-care workers and those most at risk.