LONDON, Ont. - Public health officials in Middlesex-London say their COVID-19 vaccination booking website was hit by a bot that tried to block other users from making appointments.

The region's top doctor says Verto Health, the company that owns the booking system, informed the health unit of irregular activities on the website on Monday.

Dr. Chris Mackie says the company described it as similar to what scalpers use to book concert tickets on sites like Ticketmaster.

Mackie says the bot allowed some people to bypass certain steps in the booking process and blocked out others trying to schedule appointments.

He says, however, that no one was able to book multiple appointments because Ontario health card numbers are needed to schedule shots.

Mackie adds that Verto was able to adjust the system to guard against such incidents in the future.

This report by The Canadian Press was first published March 23, 2021.