British Columbia's provincial health officer says contact tracers are ``stretched to the max'' and falling behind as they try to keep up with the province's growing COVID-19 infection rate.

British Columbia's provincial health officer says contact tracers are ``stretched to the max'' and falling behind as they try to keep up with the province's growing COVID-19 infection rate.

The latest modelling from provincial health officer Dr. Bonnie Henry came as B.C. surpassed 20,000 cases of COVID-19 with 1,130 new cases detected over two days and four more deaths.

Dr. Henry says one infection can cause a cascade of trouble and used the example of a small wedding where 15 people became positive, 10 of those had additional household cases and one person spread it to a long-term care home where three people were hospitalized and one died.

She says they are learning the virus finds it easier to transmit in cooler weather, especially while people are inside, which is why it's so important for people to reduce their contacts and step up their safety measures.

Dr. Henry points out the cases per day have doubled in the last 13 days, presenting an added challenge to breaking the chains of transmission.

A public health order restricting social interactions and other activities are in place in the Vancouver Coastal and Fraser Health regions until Nov. 23, though Henry has said it could be extended.