B.C.’s top doctor says contracting COVID-19 in the past doesn’t guarantee immunity from the virus.

Provincial health officer, Dr. Bonnie Henry is urging those who’ve had COVID, and haven’t yet gotten immunized, to get the jab.

“Over 175,000 people we know in British Columbia have had COVID-19 and many people wonder if they need to be vaccinated, and the short answer is yes,” she said. “We have looked at data from across Canada, from around the world, we’ve looked at the information around antibody levels, and one of the things that we know is the antibody levels after infection can be very varied.”

She added that some people’s immune response can be “really overwhelmed” by COVID, even with a mild or moderate infection, but particularly if they’re hospitalized, and they may not build up the long-term immunity that protects them from getting infected again.

As well, some people have a milder illness, and they may not stimulate the whole part of their immune system, according to Henry.

She said some mild infections can be fought off “and not really stimulate that cell mediated response.”

Henry also cautions that the virus continues to evolve.

She added that, like influenza, COVID can change rapidly and evade your immune response, particularly if you were infected by one of the strains that was circulating a year ago.

“It’s inconsistent in how people respond and how their immune system responds to this virus, so while many people will have a high level of protection for a long period of time, we don’t actually know how much antibody we need to protect you, long term,” Henry said.

“With the vaccine, however, we do know. We know there’s a measured amount of antigen, we know that it gives broader protection against different strains, even if they change and mutate. And we know now, from the vaccine effectiveness studies that we’ve done, both here in B.C., across Canada, and internationally, that we have a standard response that lasts for a long time from vaccine. And we know that memory cells are activated very effectively from these vaccines.”

Henry says COVID long haulers – those who have felt the effects of the virus long after contracting the virus – actually find their symptoms “get better after immunization.

“For a number of reasons, it is important, even if you’ve recovered from COVID-19, to receive a course of vaccination. It’s recommended by our national advisory committee, and it’s recommended by experts on immunology, and it is the best, longer lasting, durable, and wide-ranging protection that you can have.”