COVID-19 booster shots may be needed as breakthrough cases continue

Barrie, Ont. -

An Alliston physician says third doses of a COVID-19 vaccine for all Canadians may not be out of the question as the province begins increasing its reliance on rapid COVID-19 testing.

Dr. Barry Nathanson, Stevenson Memorial Hospital's chief of staff, says he supports the use of rapid COVID-19 testing as a measure to help identify cases and reduce transmission amongst students.

"Rapid testing has a role," Nathanson says. "It's another tool in the toolbox to keep children safe in school, to keep schools open, and to keep the population at large safer and to allow us to open up our economies and our lives more and more so."

The Alliston doctor says the tests can be helpful as long as they are only used in the context they are intended to be.

"It's much like if I can use the comparison, the pregnancy test," Nathanson says. "Its reliability is reduced in comparison to the gold-standard PCR test but not greatly so."

Expanding the province's rapid testing program comes as confusion lingers around a potential booster dose of a COVID-19 vaccine.

Some studies have shown that a third dose of an approved mRNA vaccine can provide added protection - leading countries, including the United States and Israel, to administer the additional dose to select segments of the population.

"The evidence is not 100 per cent clear as yet, but it's evolving, and it's growing, and every other jurisdiction is watching that quite carefully as are we here in Ontario and Canada," says Nathanson.

He adds the trend generally suggests that many people, if not everyone, will require a booster shot of a COVID-19 vaccine, but he expects senior citizens and those immunocompromised will receive it first.

The research into third doses comes as some studies show the effectiveness of the COVID-19 vaccine may lessen over time - one of two factors explaining why breakthrough cases, or those fully vaccinated, continue. The second is the fact that the vaccines were never said to be 100 per cent effective.

"We still have, at the best of times, approximately 10 per cent of fully vaccinated individuals who remain at risk for full-on infection, serious illness and frankly death, and that's because the vaccine, however stunningly effective it is, is 90 per cent and not 100 per cent effective," notes Nathanson.

The doctor says that while not perfect, the vaccines do continue to provide significant protection.

He says work must now be done to manage the imperfections of the vaccines.