COVID-19 Vaccination

Four vaccines for COVID-19 have now been approved by Health Canada and are being distributed across the country. The four currently approved vaccines are: 

• Moderna 
• Pfizer / BioNTech 
• Oxford University / AstraZeneca 
• Janssen (Johnson & Johnson) 

How do the vaccines work? 

The vaccines all work a little differently. The Pfizer-BioNTech and Moderna vaccines are mRNA vaccines. They work by delivering the instructions from the virus that causes COVID-19 to our own cells. This makes the body produce a small part of the virus’ outer shape – the spike protein of the virus – which then stimulates our body’s immune response and teaches it to recognize the virus should the actual virus enter your system.

The AstraZeneca and Janssen vaccines are viral vector vaccines. They use a harmless virus (such as an adenovirus, the virus which can cause the common cold) as a “delivery system” for the COVID-19 spike protein, which will stimulate your body’s immune response. This vector virus is not the same virus that causes COVID-19.  

Importantly, none of the four vaccines involve injecting people directly with the COVID-19 virus.  

Which is the best vaccine to get? 

There have been lots of reports about the “efficacy” of these different vaccines—which broadly means how well they work. We cannot make a direct comparison between the current vaccines because all of the clinical trials were done under slightly different conditions and used different metrics.  

However, what we do know is that all of the approved vaccines were 100% effective in clinical trials at preventing hospitalizations and deaths. We also know that they all have a greater efficacy than the standard Health Canada sets for approvals and that cases have dropped by as much as 80% in vaccinated populations in BC.  

This means we cannot say that one vaccine is “better” than another. The best vaccine for you is the one you are offered first. Waiting longer to be immunized is a far greater risk than taking a vaccine with a slightly lower efficacy in clinical trials.  

On April 27, Dr Bonnie Henry announced that the AstraZeneca vaccine would be available in pharmacies and clinics, as well as ‘hot spot’ areas across BC to those over 30 years old. This announcement follows an assessment from Health Canada that the risks of rare blood clots (which had led to a temporary pause in the rollout of this vaccine for those under 55), is very rare, and that the vaccine remains safe and effective. The health risks of COVID-19 – which include a much higher likelihood of blood clots – are far greater.

Read the statement from the Ministry of Health here.

When will I get my second dose? 

Three of the four approved vaccines in Canada require two doses for maximum protection (the Janssen vaccine is single-dose), although there is strong evidence that a single dose provides very high protection for several weeks. The recommended window between the first dose and the second “booster” dose of all COVID-19 vaccines in British Columbia is currently a minimum of around 8 weeks.  If it has been longer than 8 weeks since you received your first dose, however, this does not mean the second dose is ‘late’; in some cases there is even evidence that waiting a little longer can provoke a better immune response.

On June 3, the Provincial Health Officer also announced that ‘mixing and matching’ between the three vaccines for first and second doses is safe and effective. In general, those who received Pfizer and Moderna vaccines for their first dose will get the same brand for their second dose; however, depending on the supply at the time, some individuals may be offered the other mRNA vaccine.  Those who received Astrazeneca for their first dose will be able to choose which they receive for their second dose (see this infographic for more details). For people who wish to receive Astrazeneca for their second dose also, they are likely to be contacted by their pharmacy. For those who choose to receive an mRNA vaccine for their second dose, this can be booked through the Get Vaccinated website around the 8-week point. This is a matter of personal preference and risk; evidence shows there is no particular ‘better option’.

In general, second doses of COVID-19 vaccines are being coordinated through the province’s Get Vaccinated website. Even for those who got their first dose before the website launched in April, the system will have a record of the date of your first dose and will send an invitation to book an appointment at a clinic for the second dose.

In some health authorities (in particular Vancouver Coastal and Island Health), the additional option to receive a second dose at on-site clinics in long-term care or assisted living settings may also be available. If this is the case, managers will have been contacted by their health authority about these clinics. Regardless, we recommend that everyone take a few minutes to register via the Get Vaccinated site, as this is the easiest way to guarantee access to your second dose.