MONTREAL -- Quebec's decision to delay the second dose of the Pfizer COVID-19 vaccine this week to inoculate as many people as possible with a first dose is causing concern for some health-care professionals working on the front lines.

The Ministry of Health said Dec. 31 that it would not hold back doses for the second "booster shot" for those who have already received a first shot. 

"Note that the effectiveness of the first dose, 14 days after administration, is over 90 per cent for both vaccines (Pfizer and Moderna)," Quebec said.

"The second remains important, mainly to ensure long-term protection. It should be administered within the time limits prescribed by public health in order to ensure maximum immunization coverage. The appointments of people already vaccinated to receive their 2nd dose will be adjusted accordingly."

The news left one nurse at the Jewish General Hospital stressed and anxious.

"They now claim that we are 90 per cent immune with a first dose when they were telling us all along that it was 60 per cent covered," said the nurse who wished to remain anonymous. "Where’s the proof of the 90 per cent coverage. We are exhausted and desperate for help."

Another nurse wrote a response to the CIUSSS when she received the letter informing her that her second dose was cancelled.

"I did not consent to receive one dose of a very new vaccine without the booster 21 to 28 days afterwards as intended," wrote Sarah, who wished to only use her first name.

"This is not how the vaccine has been scientifically demonstrated to work. Despite the fear of taking a new vaccine, I did my research and laid my trust in Pfizer, the CIUSSS as well as the ministry of health. Now, the new recommendation shifts to a more haphazard approach of mass vaccination. I am extremely disappointed and think this strategy will breach the trust of many employees as well as the public, just as mine has been."

Nathan Friedland is a nurse at Lakeshore General Hospital, which has suffered immensely from staff shortages, outbreaks and other logistical issues. He has not been vaccinated and welcomes Quebec's decision. 

"I happen to think Quebec is making the right decision here: vaccinate as many as possible right away especially with the latest projections from INESSS," he said.

"What should now happen is that they take those 27,000 vaccines they were going to hold and give them to the staff in the ICUs and ERs because we are about to get overrun with COVID!"

The decision is in line with other health authorities such as Ontario and the UK, which decided not to hold back half of its vaccines for second vaccinations.

Health Canada says that for the Pfizer-BioNTech COVID-19 mRNA vaccine to work best you need two doses 21 days apart. Based on studies of around 44,000 participants, Health Canada says, the vaccine "was 95 per cent effective in preventing COVID-19 beginning 1 week after the second dose."

Pfizer director of corporate affairs Christina Antoniou repeated this saying the vaccine is to be administered 21 days apart, and that individuals may not be optimally protected until at least seven days after their second dose of the vaccine. 

"We consider it to be a safe approach for the vaccination points of use to continue storing a portion of the doses received, to ensure no delay in the second dose deployment," said Antoniou.

"It’s a conservative approach that we have recommended to ensure that both doses of the vaccine are delivered according to the schedule in the product label (i.e. 21 days apart)."

She added that it is the responsibility of the provincial health authorities to determine their immunization program, however.

When asked how long before the first dose becomes ineffective without the second, Antoniou said Pfizer does not have that data.

"We do know that it takes about two weeks after the initial dose to develop an immune response, but that two doses are necessary," she said.

"In our clinical trial, the two-dose regimen of the vaccine, which was given 21 days apart, was well-tolerated and demonstrated vaccine efficacy of 95 per cent against COVID-19. There is still much to learn about the disease, and the protective nature of the vaccine will continue to be studied."

Sarah wished the CIUSSS would have protested the government's decision and refused the new approach.

"Let people who received the first dose already get their second. My second dose is in just a few days," she said.

"Switch the strategy after letting people receive their booster if they already received a first dose. If people still choose this way of vaccination, great! Give people the choice to do it this way... My choice has been stripped by the government. My bodily autonomy has been taken away."

Quebec has received 55,000 Pfizer and 32,500 Moderna vaccines.

As of the last COVID-19 update on Dec. 31, the government of Quebec reported that 29,250 vaccines had been administered in the province.