South Africa is currently experiencing another wave of the omicron strain of COVID-19, this time with the latest subvariants of the virus, BA.4 and BA.5.
The two newest subvariants of the COVID-19 virus are shown to evade natural immunity, which means if you’ve had a COVID-19 infection previously, it won’t make much of a difference in terms of how sick you’ll get if reinfected. However, being vaccinated and boosted will help protect you from serious illness.
“What’s published suggests that if you’ve had prior infection with BA.1 then your antibodies aren’t as effective against BA.4 and BA.5 subvariants, so you are more likely to be reinfected if you’ve just had omicron BA.1,” explains Daniel Gregson, a Calgary-based physician who specializes in infectious diseases and medical microbiology.
The data on people who’ve been immunized suggests that if you've had omicron then your antibody levels remain more active against the BA.4 and BA.5 than if you’ve just had prior infection.
Gregson says this is something researchers have noticed before with other variants.
“In the alpha wave, we noticed immunization was more protective against re-infection than prior infection,” he says. “With omicron, the BA.1 variant, that third dose of vaccine gives you the most protection. And you’ll probably see the same thing with BA.4 and BA.5. If you’ve had three doses you’re still going to have moderate protection from hospitalization but you’re probably at risk of having a cold.”
To date, there haven't been any reported cases of the newest omicron subvariants in Canada but Gregson says it’s only a matter of time. So far, there been reported cases in England, Denmark, Scotland and the U.S.
“There are cases of it in the United States so we’re going to see this in Canada,” he says. “There’s no real barrier. All you can do is slow it down a little bit. There’s no data right now that suggests we can do that. The more important information that seems to be coming out is that immunization is more important than previous infections.”
He adds that if you’re already been infected with but haven’t been vaccinated, now is the best time to do so.