Is it time for your COVID booster? New federal guidelines tell you

For those wondering if and when they should get their next COVID-19 booster shot, federal health officials have released new guidance.

Beginning in spring, an additional booster dose is recommended for adults 80 years of age and older, or those living in long-term-care homes or congregate living settings, either for seniors or those with complex medical-care needs, according to the National Advisory Committee on Immunization (NACI) guidance released Friday.

NACI also recommends that those 18 and older who are moderately to severely immunocompromised due to an underlying condition or treatment, as well as those between the ages of 65 and 79 if they haven’t had COVID-19, seek a booster.

“I think that’s smart policy because if you look at who is most likely to end up in the hospital or have bad outcomes, it’s this group of people,” said Dr. Fahad Razak, internal physician at St. Michael’s Hospital and former director of Ontario’s COVID-19 science advisory table.

As for the individuals who don’t fit into those categories, at this time NACI is only recommending another dose if they haven’t already received previously recommended doses — their initial two or three doses of vaccine and any type of booster this past fall.

NACI added they expect that enough supply of COVID-19 bivalent boosters will be available for recommended groups.

Vaccine protection against infection and symptoms has been shown to wane over time with the original monovalent COVID-19 vaccines, though according to NACI, protection against severe outcomes lasts longer than protection against symptomatic disease.

“Vaccine effectiveness against severe disease from booster doses is generally higher and more sustained than against infection,” NACI added.

The committee’s guidance added that some Canadian data suggests vaccine protection may reach a plateau for adults with hybrid immunity — those who had at least one exposure to COVID-19 and at least one vaccine dose.

NACI said those with hybrid immunity demonstrated little benefit from booster shots of the original mRNA vaccines in certain specific circumstances — health-care workers got little extra protection against infection/symptomatic disease from the Omicron subvariant BA.2; and non-institutionalized elderly populations gained little protection against hospitalization due to the Omicron subvariants BA.1, BA.2 and BA.4/5. (Current epidemiology shows Omicron sublineages continue to be the dominant strain of the virus.)

With testing no longer widespread and routine, Razak said researchers are relying on wastewater data to determine how much virus is spreading. That data shows a possible rise in infections over the last few weeks in Ontario.

“It’s remained relatively high now for over a year or so since Omicron first emerged — it’s never really gone down to very low levels like we saw previously between waves,” Razak said, adding this suggests that Omicron subvariants like BA.5, BA.2 and XBB.1.5 are each triggering a new wave of infections.

The good news, Razak said, is there hasn’t been a “meaningful rise in hospitalizations” right now. Razak credited this to prior infections and vaccinations leading to some level of durable immunity against severe disease in the population as a whole.

Dr. Isaac Bogoch, infectious disease physician, called the guidance a reasonable approach and added that we may see recommendations change with time.

“We know there’s various groups that are at much lower risk for severe COVID-19 who’ve already had two or three or more doses of vaccine and perhaps those groups aren’t really going to benefit much from a vaccine at this point in time,” Bogoch said, reiterating that this could change.

To help prevent infection and spread of COVID-19, Razak said it makes sense for the general population to wear a mask in crowded indoor settings like transit and grocery stories.

“Even if you’re not at high risk of ending up in hospital, infections can be very disruptive. It could be missed work, it could be missed family events, it could be missed school,” Razak said.

NACI said it will continue to monitor COVID-19 across the country as well as new evidence on vaccines, and will update recommendations if necessary.