LONDON, ONT. -- London health officials say the region's vaccine supply is about to drop, with hot spot designations that fail to reflect the current realities prompting COVID-19 vaccines to be sent to other areas.

Middlesex-London Health Unit Medical Officer of Health Dr. Chris Mackie says the supply of the Pfizer BioNTech vaccine coming to the region is about to drop by almost 30 per cent.

Speaking at the Board of Health meeting Thursday night Mackie said, "We have been receiving 12,870 Pfizer per week. That will be down to 9,360 in about a week's time. At the same time you've seen case counts here climbing dramatically to the point where we're very similar to those GTA hotspots."

As cases in the London region climb, he added that hot spot designations aren't keeping pace with regional surges.

"The challenge with the decision is that it doesn't seem like the definition of hot spots is being updated. This community was not a hotspot three weeks ago when the decision was made and we're seeing our vaccine allocation being cut now by about 27 per cent in terms of Pfizer allocation over the next couple of weeks."

In fact, based on current data, Mackie says the London region currently has one of the highest rates of infection in the province.

"The rate per hundred thousand is the fifth highest in Ontario, behind only three GTA communities and Ottawa. Otherwise, this is the highest community in cases per 100,000 in the province. Vaccine allocations do not reflect that. So that's a challenge."

And the reduction in supply doesn't take into account an already slower-than-expected roll-out of the Pfizer vaccine.

"All health units were supposed to have received, as of next week, enough vaccine to vaccinate 40 per cent of the population. That was a commitment from the premier and that was based on data the Ministry of Health supplied the premier with. It looks like we're off by between 20,000 and 35,000 thousand doses here. We won't be able to hit that mark," Mackie says.

It's unclear whether the issue is unique to the London region or whether there is an issue with the methodology used to determine what areas are hot spots, Mackie added.

Mayor Ed Holder says he's already brought his concerns about hot spot designations to Premier Doug Ford's office, but now the health board has directed chair Maureen Cassidy to do the same.

Board member, Councillor Arielle Kayabaga, explains, "That the chair sends a letter to provincial government to advocate for London North to be considered as a priority area for vaccines as it is currently as hot spot."

As it stands, Mackie says the reduction in Pfizer BioNTech vaccine may result in one of the three mass-vaccination clinics being temporarily idled.

Meanwhile, the region's pharmacies and doctor's offices are expected to receive 15,000 to 20,000 doses of the Astra Zeneca vaccine, but there is no timeline for their arrival.