MONTREAL -- Faced with a rise in outbreaks, Quebec Health Minister Christian Dube announced Tuesday that seniors living in residences will be offered a third dose of a COVID-19 vaccine.

He made the announcement during a vaccination campaign update, accompanied by the province's public health director, Dr. Horacio Arruda, and the head of Quebec's COVID-19 vaccination strategy, Daniel Paré.

"If we look at the last few weeks, we see that we are starting to have outbreaks again in what we call our living environments," Dube said referring to the province's long-term care homes (CHSLD, RPA).

About 250,000 seniors are eligible for a third dose.

Dube said immunization experts have recommended a six-month interval between second and third doses, and, thus, mobile units will be deployed at the end of October to those living environments.

Arruda said the reason elders at home will not be a priority is due to the risk of infection being greater in residences than at home. If the situation changes, seniors living at home will be added to the priority list.

"If there is a risk to those persons, we'll do the same thing," he said.

There are currently 140 active COVID-19 cases in Quebec seniors' homes, including an outbreak at a facility in Mirabel.

The elderly are more at risk of infection because their immune system is weaker, as the antibodies from the first two doses wear off and variants become a bigger threat.

"When the body's immune system starts bringing things down because that's how it normally behaves, but then there's a lot of variants," said infectious disease specialist Dr. Donald Vinh. "You can see why there would be a need for boosters. What we don't want is to find ourselves where we were a year and a half ago, but this time with variants, decimating our elderly again."

Dube said that a third dose could soon be offered to more Quebecers.

"We will await for the recommendation of our experts for other age groups," said Dube.

In August, the Quebec Institute of Public Health (INSPQ) recommended that Quebecers on dialysis or who are immunocompromised get a third dose of vaccine, but didn't advocate for seniors. Now, the INSPQ is recommending the booster shot for seniors.

Quebec's plan for a third dose follows Ontario, Saskatchewan and Alberta. The U.S. is recommending anyone over 65 years old get a third shot. Arruda said in the States, there was a shorter time between first and second doses.

" The U.S. used a vaccine with 21 or 28 days interval," he said. "There's a lot of data saying they had to revaccinate people because the interval was too low. We waited 16 weeks and that made our antibody response better."

The health minister said though the numbers have plateaued and the number of hospitalizations is also expected to stabilize, the Delta variant and outbreaks continue to occur.

"We must remain careful," said Dube. "In general it's the unvaccinated people who get the sickness."

COVID-19 cases have spiked in the last two months in Quebec, mostly due to the highly contagious Delta variant that is leading the fourth wave.

Arruda said no new measures aside from the mandatory mask and physical distancing orders would be required.

"Even though you have two doses, you can still spread the virus. We shouldn’t drop all of our health restrictions,” he said.

With the Oct. 15 deadline approaching for health-care workers to be fully vaccinated, Dube said that 7,000 health-care workers who are in contact with patients have yet to be fully vaccinated.