1st dose of COVID-19 vaccine provides 80% protection 14 days after administration

An article published today reports that 32% of the 78 MUHC employees infected with COVID-19 last February, or 25 employees, had received a first dose of the vaccine.

It is important to note that of these, at the time of diagnosis, 12 employees had been vaccinated for less than 14 days, and 13 had been vaccinated for more than 14 days.

Efficacy studies show that the vaccine provides 80% protection approximately 14 days after the first dose. In the first few days after the first dose, no efficacy is expected because it takes time for the immune response to become active. Of MUHC employees who were vaccinated for more than 14 days and were diagnosed as positive, only 15% became infected, which is consistent with the effectiveness of the first dose.

The MUHC is following the Public Health recommendation to offer the second dose of the COVID-19 vaccine 16 weeks (four months) after the first dose, thereby significantly increasing protection for vulnerable Quebecers.  The MUHC is also actively pursuing a campaign to promote vaccination among its employees.  As of March 10, 2021, close to 9,500 MUHC healthcare workers have been vaccinated against COVID-19 out of a total of approximately 13,000 employees in priority groups, including physicians. We will vaccinate administrative personnel and employees who are not in direct contact with patients, when their turn comes.