Vaccination: your questions & our answers (public & employees)

Ask the Experts: a series of videos to learn more about vaccination.
  •  CLICK HERE to meet the experts at our CIUSSS and answer all your questions.

Information on COVID-19 vaccination
Questions and Answers for Employees and the General Public

1. How safe are the COVID-19 vaccines?
Health Canada always conducts a thorough review of vaccines before authorizing them. Thus, the Pfizer and Moderna vaccines have been treated like any other vaccine that is approved for use in Canada: They were subjected to rigorous scientific standards of quality and to clinical trials, and now they are undergoing post-marketing surveillance. Since January 2021, active surveillance of clinical characteristics has been added to the usual surveillance system. For anew COVID-19 vaccine to be administered in Quebec, follow-ups must be undertaken with 30,000 people to document the occurrence or worsening of a health problem that is serious enough to require a medical consultation within seven days before and seven days after vaccination. The risk of a severe allergic reaction is extremely rare: just one to two chances in one million people. No one can be infected with COVID-19 by being vaccinated, since the vaccine does not contain the virus. It contains only a small part of the genetic code of the virus (RNA messenger).

2. What are the differences between the Pfizer and Moderna vaccines?
Although both vaccines contain messenger RNA, there are several differences in the non-medicinal ingredients. In addition, the participants in Pfizer’s study were at least 16 years old, whereas Moderna’s study included participants over the age of 18. A major difference is the storage temperatures:-70oto-80oC for Pfizer, and -20oC for Moderna.Side effects, contraindications and efficacy results in the studies’ trials were very similar. Both were found to be very effective at preventing serious illness, hospitalizations and deaths. It is important to remember that the objective of both vaccines is the same: to help bring an end to this pandemic.

3. How effective are these vaccines after one dose?
In clinical trials conducted by Pfizer and Moderna, vaccine efficacy was over 90% 14 days after the first dose was administered. Recently, the Institut nationale de santé publique analyzed vaccine efficacy after a dose was administered. It found that healthcare workers and residents of CHSLDs showed a high efficacy of 80% after 21 days. It should be noted that maximum efficacy after one dose may not be reached before 21 days in younger people, and before 28 days in older people (Comité sur l'immunisation du Québec (CIQ) - February 18, 2021). Given the efficacy obtained after the first dose, the CIQ recommends postponing the second dose, in case of a vaccine shortage and the very rapid spread of COVID-19 in Quebec. Instead, the vaccine should be given to people in the priority groups as quickly as possible (MSSS - January 20, 2021).

4. What are the new COVID-19 variants? Do the current vaccines protect us against them?
Like other viruses, COVID-19 regularly undergoes transformations into new variants. These (the UK, Brazil and South Africa variants) are thought to be more contagious and/or more virulent than the initial COVID-19 virus. So far, the Pfizer and Moderna vaccines have been able to protect us from these variants. Moderna and Pfizer have produced research findings that show the antibody response to the South African variant is lower, but still enough to protect us.

5. How long does the efficacy of one dose last?
To date, as announced by the Institut nationale de santé publique (INSPQ) on February 17, vaccine efficacy of 80% is maintained for eight or nine weeks after the first dose is administered. It is too early to determine at what point a decrease in efficacy might occur, since the maximum follow-up period is two months for those who have been vaccinated. The studies are ongoing and the data are analyzed on a weekly basis (Comité sur l'immunisation du Québec (CIQ) - February 18, 2021). The CIQ reminds us that administering a second dose is important to ensure long-term protection (INSPQ - January 20, 2021). Since there has been no alert about a vaccine shortage, a longer (rather than shorter) interval is preferred, in order to maximize the protection of the greatest number of people (CIQ - February 18, 2021).

6. What is the rationale for modifying the dosing schedule and not adhering to the Pfizer/Moderna protocol?
In January 2021, clear evidence was found for the increased spread of the virus in the community, as well as an increase in the number of hospitalizations, ICU admissions and deaths. Quebec Public Health warned that our healthcare system was facing a serious threat, and six vulnerable groups were identified. Healthcare workers were included, because they are at greater risk of contracting COVID-19 and are vital to the healthcare system. Rapid vaccination of these groups was believed to be the most effective way to reduce the trend. These groups comprise 1.7 million people. Based on the number of vaccine doses that Quebec was expected to receive in early 2021, it would be impossible to vaccinate these priority groups with both doses in time to prevent our healthcare system from reaching the breaking point. Data from Pfizer and Moderna showed that after the first dose (at day 14), the vaccine is at least 90% effective. The recommendation from the Comité sur l’immunisation du Québec(CIQ) was to offer the first dose to the largest number possible in the six priority groups. The Health Ministry is keeping track of the level of protection provided by the first dose. The preliminary results, reported recently by the CIQ, show that after two months, strong immunity exists after one dose in healthcare workers and in long-term care residents. If a decline is observed, the plan will be modified and the administering of the second dose will be sped up (Institut nationale de santé publique, December 2020). Rest assured that the current plan is for the second dose to DEFINITELY be administered, since it is required for long-term protection.

7. Is there enough data to support the decision to delay the second dose?
Experts from Quebec Public Health carefully evaluated the results of the studies by Pfizer and Moderna. Based on their analysis and the very real threat to our healthcare system, they recommended delaying the second dose, in order to administer the first dose to the greatest number of people in the most vulnerable groups. The goal is to decrease the incidence of serious illness, hospitalizations and deaths, and to protect the integrity of our healthcare system (Institut nationale de santé publique (INSPQ) -December 2020). The study’s results demonstrate at least 90% protection after the first dose. In reality, these figures are not surprising. For many vaccines that routinely require more than one dose, it is the first dose that by far provides the most protection. These include vaccines against whooping cough, measles, mumps, rubella, chicken pox and hepatitis A. The additional doses assure long-term protection (INSPQ, December 2020). What’s certain is that if people are not vaccinated, they are at risk of contracting COVID-19 and developing complications.

8. What is being done to monitor the impact of delaying the second dose?
Careful, continuous monitoring of vaccine effectiveness nearly in real time will take place throughout 2021. This will allow adjustments to be made, if necessary, to the public health immunization strategy.

9. Will we get access to our second dose if the duration of the efficacy is shown to be short?
Yes. The administering of the second dose will be sped up if the efficacy studies by the National Institute of Public Health show a rapid decline in protection after the first dose. The Comité sur l’immunisation du Québec recommends that if there is a shortage, and if a high level of the virus is circulating, the first dose of the COVID-19 vaccine should be given to as many people as possible in the first six priority groups. Once they have received their first dose, the second dose can be offered, if the efficacy studies show a decline in protection after the first dose.

10. I’ve heard that we will not get our second dose. Is this true?
No, this is not true. As per the Ministerial directives, once the priority groups have been vaccinated, and as soon as more doses become available, you will be advised when and where to get your second dose.

11. How long will the second dose be delayed?
The Comité sur l’immunisation du Québec recommends that if a shortage exists, and if the virus is circulating at a high level, the first dose of vaccine should be offered to as many people as possible in the first six priority groups. Once all of these people have received their first dose, the second dose will be offered. The MSSS will determine when the second dose will be given. In addition, administering the second dose might be anticipated, if the efficacy studies by the Institut nationale de santé publique show a rapid decline in protection after the first dose.

12. How is the decision made to give priority to certain employees for vaccination?
In mid-December 2020, the Comité sur l’immunisation du Québec published a directive about prioritizing healthcare workers for COVID-19 vaccinations. It outlines the order in which the vaccines are to be given, as well as establishing the order for it to be given by establishment, department and job title.

13. How are these measures being put into place?
Our CIUSSS is following a directive of the Comité d’immunisation du Québec(published in December 2020) on prioritizing healthcare workers who are to receive the COVID-19 vaccine. Human Resources and various other departments are working together to ensure that all employee lists are validated and that all those who are eligible to receive the vaccine are called in their order of priority. If you think you have been overlooked, please speak with your line manager.

14. Can my family members be vaccinated?
Our CIUSSS is following the vaccination priorities for groups listed by the Programme d'immunisation du Québec. Healthcare workers are included in the first phase of vaccination. In the second phase, your family members will be eligible when vaccination begins for the priority group to which they belong. The vaccine will be administered by the healthcare network in the area where your family members live.

15. What are the contraindications of these vaccines?
You should not be vaccinated if you have had a serious allergic reaction to a first dose or if you have a known allergy to any of the components of the vaccine, such as polyethylene glycol (PEG). The list of components is readily available online.

16. Is pregnancy a contraindication?
Pregnant women have the option of receiving the vaccine at any time, if they are eligible and have no contraindications. This decision is based on their personal values and their understanding that the risk of infection and complications from COVID-19 infection outweighs the theoretical or unstudied risk of vaccination during pregnancy. Women should not be denied the vaccine solely because they are pregnant. Severe infection by the COVID-19 virus carries risks to the health of the mother and fetus (Society of Obstetricians and Gynaecologists of Canada - February 1, 2021). Each pregnant woman is urged to speak with her treating physician. If she decides to be vaccinated, she should have a doctor's prescription for the COVID-19 vaccine.

17. Is trying to become pregnant a contraindication?
If you are planning a pregnancy, it is recommended that you complete the entire COVID-19 vaccination series (where possible) to achieve maximum vaccine efficacy before pregnancy. It is not known whether pregnancy should be delayed after vaccination. Therefore, a risk-benefit discussion with your physician is recommended (Society of Obstetricians and Gynaecologists of Canada - February 15, 2021). In Canada, the Comité consultatif national de l’immunisation (CCNI) recommends waiting 28 days after the end of the vaccination cycle before becoming pregnant (CCNI, January 12, 2021).

18. Is breastfeeding a contraindication?
Breastfeeding women have the option of receiving the vaccine at any time, if they are eligible and have no contraindications. This decision is based on their personal values and their understanding that the risk of infection and/or complications from COVID-19 infection outweighs the theoretical or unstudied risk of vaccination during breastfeeding. Women should not be denied the vaccine solely because they are breastfeeding (Society of Obstetricians and Gynaecologists of Canada - February 1, 2021). The Comité sur l’immunisation du Québec is of the opinion that although there are not yet sufficient data about vaccinating breastfeeding mothers, the benefits of vaccination outweigh the risks for mother and child alike. It is recommended that each breastfeeding woman speak about the risks and benefits of the vaccine with her treating physician. A medical prescription is not required, in order to receive the vaccine.

19. What are the expected side effects?
Side effects that have been reported by people who received the Pfizer and Moderna vaccines. In addition, the studies reported that the side effects for the first and second dose appear to be a bit more pronounced in those under the age of 55. Most of these reactions tend to be light to moderate, and they disappear within a few days. Local side effects include pain, swelling or redness at the site of injection. Pain at the injection site is the most commonly reported local side effect. Among the systemic side effects are fatigue, headache, chills, muscle pain, joint pain and swelling in the lymph nodes under the arm. Fever sometimes occurs, but is typically less than38.9oC. Fatigue and headache are the most commonly reported systemic side effects. Some participants in the Pfizer and Moderna studies reported that the side effects were a bit higher in intensity after the second dose. However, this is a simply a sign that the immune system is doing its job.

20. Can I be vaccinated if I previously tested positive for COVID-19?
Yes. However, Quebec and Health Canada have decided to give the vaccine only to individuals who have not been diagnosed with COVID-19 in the previous three months. Once three months have passed since the date of your most recent positive test, you can receive the vaccine. This requirement will be reviewed as vaccine supplies increase.

21. Can I be vaccinated if I currently have COVID-19?
It is recommended that you wait until you have no symptoms. This waiting period helps prevent a contagious person from showing up at a vaccination site and infecting others. You are still likely to be at risk for serious infection for a few months after infection, although the risk is lower. Therefore, you might consider delaying vaccination until three months after your diagnosis (MSSS - January 4, 2021).

22. Can I still transmit the virus if I have been vaccinated?
Yes. You can infect another person, even if you have been vaccinated. In addition, you may be a carrier of the virus, even if you have no symptoms. It is your responsibility to continue obeying the infection prevention and control rules.

23. If I, my family members and my friends have been vaccinated, do I still need to wear a mask?
Yes. Otherwise, you may contaminate people outside your immediate group. You may also still be a carrier of the virus without being infected. You must continue to obey the rules of infection prevention and control during your daily activities.

24. How can I obtain proof that I have been vaccinated with the first dose?
Proof of vaccination is currently available at the vaccination site. Any employee who was vaccinated before this type of proof was available will be able to obtain proof when they get their second dose (confirmation that both doses were received). If you would like proof as soon as possible that you have been vaccinated with your first dose, you can complete the form at the link below and send it to Chantal Desmarais at:

CIUSSS West-Central Montreal
3755 Côte Sainte-Catherine Road
Montréal (Québec) H3T 1E2
Fax: 514-340-7556

There may be an additional delay, due to a greater volume of requests or the temporary unavailability of the information that is being sought.

25. What should I do if, after being vaccinated, I develop COVID-like symptoms?
Clinical post-vaccination symptoms may resemble symptoms of COVID-19. For this reason, you should be alert to the presence of one or more symptoms, such as fever of 39°C or higher, difficulty in breathing, loss of taste and/or smell, cough, sore throat or unusual headache. If have any of these symptoms, please contact the COVID-19 Employee Hotline at 514-731-7343 between 8:00 a.m. and 6:00 p.m., seven days a week, to have your situation assessed. Also, you should not report to work.

26. How much time does it take to obtain the result of a COVID-19 test at the Légaré trailer and at Pavilion N?
Our CIUSSS communicates the results to those who have been screened within 24 to 48 hours from the time when the laboratory results are received. Laboratory analyses are done according to government priorities. Therefore, the results may be communicated to you a few days after you have been screened.

27. How can I schedule an appointment to be vaccinated?
Staff members will be vaccinated by the CIUSSS, based on priorities established by the MSSS. Eligible staff will be contacted by telephone and given all of the details when their time comes to be vaccinated. Those without an appointment will not be permitted to enter the vaccination site. If you are concerned that you have been overlooked, please talk with your manager.

28. How long does it take to get vaccinated and why do I have to wait around?
The entire process, including registration and assessment, takes 30 to 60 minutes. After you receive your vaccine, there is a remote chance that it may cause an allergic reaction. This occurs almost immediately after the vaccine is administered. Therefore, for your own safety, you will be asked to stay for 15 to 30 minutes after you have been vaccinated.

29. Do I have a choice of which vaccine I receive?
No. Rest assured that all of the vaccines are safe and will protect you.

30. Can I mix and match vaccines?
At the moment, this is not recommended, but this subject has raised a great deal of interest. Studies are being conducted in the U.K. and the results should be available in the coming months.

31. Will the new vaccination strategy also be used for the public? In other words, is it possible that the second dose for healthcare workers will delayed, but as more doses are produced, people with a lower priority will still be vaccinated within the manufacturer recommended timeframe?
The CIQ’s recommendation is to delay the second dose for all current vaccinations. This measure will remain in effect, until the MSSS declares otherwise.

32. Can we travel after receiving two doses of the vaccine? When I return, what are the implications for my job, if I travel abroad—for example, for the birth of a grandchild? I realize I would have to quarantine on returning. I am able to work from home.
The availability of COVID-19 vaccines does not mean we can discontinue the public health measures that are now in place. You are strongly urged not to travel outside Canada or Quebec, and not to move between COVID-19 zones locally or provincially.

If you decide to travel outside Canada, you must self-isolate for 14 days upon returning. As stated in the ministerial guideline, you will not be remunerated, unless you qualify to work from home and receive authorization from your manager. Also, if you travel, you may not be covered by insurance. In addition, you will also be obligated to bear the consequences of any problems that may arise—e.g., unexpected medical expenses and flight cancellations. You will not be eligible for salary insurance if you become infected with COVID19 outside the country.

33. Is written consent required before I am vaccinated?
Yes. You must complete and sign a consent form to receive the vaccine. It will be sent to you by email or given to you by your manager before your appointment. In addition, pregnant women are asked to have a discussion with their attending physician and to have in their possession a medical prescription to receive the COVID-19 vaccine.

34. What number should I call with questions about COVID-19, such as testing, isolation protocols and vaccination?
You can contact the COVID-19 Employee Assistance Line at 514-731-7343, from 8:00 6:00 p.m., 7 days a week.

35. Whom should I speak to if I have questions about any COVID-related premiums that must be paid?
Please speak with your manager.

36. What are my options for a second dose if I received one dose of AstraZeneca? 
For people younger than 45 years of age who received the Covishield or AstraZeneca vaccines as a first dose, it is recommended they receive Pfizer or Moderna as the second dose. However, if they wish, they may receive Covishield or AstraZeneca after being informed of the higher risk of thrombosis with thrombocytopenia for that age group (see below) and that it is recommended they get Pfizer or Moderna as a second dose. 
For people 45 years of age and older who received the Covishield or AstraZeneca vaccines for the first dose, the same vaccines can be administered for the second dose. A person may also receive a dose of mRNA vaccine (Pfizer or Moderna) for the second dose if they prefer, depending on the doses that will be available in Quebec. Studies show that people who receive two different vaccines may experience more pronounced side effects following the second dose, such as fever, headache and fatigue. These side effects resolve within a few days.  

37. Is it safe to get the AstraZeneca vaccine as a second dose? 
The Covishield and AstraZeneca vaccines are safe and provide highly effective, long-lasting protection.  
Note that cases of thrombosis with thrombocytopenia are considered to be a possible complication of the Covishield and AstraZeneca vaccines. This is very rare (1 case in 60,000 vaccines administered as a first dose). When the second dose is administered, the rate is even lower, 1 case in 600,000. 

38. If I choose to get Pfizer or Moderna as my second dose, will it be effective? 
Mixing different vaccines has been used as a strategy for vaccines against other disease in the past, such as hepatitis vaccines. Studies are underway on the immune response obtained when vaccines against COVID-19 are mixed.  
Preliminary studies have shown that providing an mRNA vaccine after AstraZeneca will boost the immune response, producing high levels of antibodies, which is what is expected from a second dose. 

39. What is the best interval between getting my AstraZeneca shots? 
In Quebec, the interval currently recommended for the administration of the second dose of AstraZeneca is 8 weeks or more in order to obtain maximum protection.  
The second dose of the AstraZeneca vaccine is available as of May 29, 2021. (

40. What is the interval if I choose to receive an mRNA vaccine as my second dose instead of AstraZeneca? 
A person may prefer after informed consent to receive a dose of mRNA vaccine (Pfizer or Moderna) as a second dose. The second dose can only be given 8 weeks after the first dose. According to recently published data on this type of vaccination strategy, people who receive two different vaccines are likely to experience more severe side effects in the days following the second dose, such as fever, headache, and fatigue. (

41. Can I receive AstraZeneca or Covishield as my second dose if I got Pfizer or Moderna as my first dose? 
This is not currently recommended.

Page last updated on 

We always seek feedback to make our site better.