Coronavirus outbreak hits Quebec's first vaccination site, public health says 'it's expected'

On Dec. 11, as the Quebec City health region was preparing to administer the first Canadian doses of the COVID-19 vaccine, two residentsat the CHSLD Saint-Antoine tested positive for coronavirus.

The next day,15 more did. The people affectedwere from a single unit and werequickly isolated.

Officials had plannedto inoculate the facility's 230 or so residents partly to testwhether the vaccine could inhibit the virus's spread in an extended-care facility where it wasn't already present. It now appears that byDec. 14, the day the first shots were administered, it was too late.

More than 80people at the centre, including 66 residents, havetested positive for the novel coronavirus since receiving the first of two vaccine doses.

The vaccine itself contains no viral or infectious materialand the outbreak should not be taken as an indication that it is not effective, a health regionofficial stressed.

A spokesperson for the CIUSSSde la Capitale Nationale said positive tests and resulting cases of COVID-19 were always likely. According to the evidence from clinical trials, it can take up totwo weeks to achieve 50 per cent immunity, and a second dose is required after 21 days to reach95 per cent.

"We expected there could be more cases among staff and residents who are vaccinated, because they've only had one dose of the vaccine," Mlanie Otis said in an email.

According to the health region, 202 residents took the vaccine, along with 125 staff. It seemslikely several of them were already infected with the coronavirus when they received the shot, Otis indicated.

In any case, immune responses aren't typically instantaneous, Dr. Jacques Girard, the medical adviser to Quebec City's chief public health officer, told Radio-Canada's Premire Heure.

"When we give someone a vaccine it's to protect them," but hecautioned that it often takes a couple of weeks to develop sufficient antibodies to stave off the virus, meaning that as of this week there should be signs the outbreak at CHSLD Saint-Antoine is starting to recede.

Residents and staff will begin receiving their second dose of the serum beginning Jan. 4.

Protection still key after vaccination

It wasn't immediately clear how many of those who have tested positive for the coronavirus are symptomatic or have come down with COVID-19. As it stands, a total of 51 residents and 50 staff are positive.

"The situation at CHSLD Saint-Antoine demonstrates the importance of protecting oneself even after vaccination. And even if the vaccine provided real protection after one dose we know the virus can still transit through certain people," Otis said.

The experience in Quebec Cityto this point lends credence to the belief previously expressed by some scientists that while vaccination is goodat protecting people against getting desperately sick, it may not inhibit spread.

Another factor to consider, Otis said, isthe clinical trials for the vaccine weren't held in a long-term care environment that is dealing with an incipient outbreak.