What are COVID-19 vaccines?
COVID-19 vaccines protect against infection from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes COVID-19. The vaccines cause your body to produce antibodies that will help protect you from getting sick if exposed to the virus.
Currently, there are four COVID-19 vaccines approved for use in Canada:
- Moderna
- Pfizer-BioNTech
- AstraZeneca & COVISHIELD
- Johnson & Johnson (Janssen)
For information on the vaccines and registration, please go to https://immunizebc.ca/covid-19 . Everyone is eligible for the vaccine, regardless of your immigration status.
For information on socializing and having sex after the vaccine, visit the socializing section on our page.
How effective are the COVID-19 vaccines?
How our immune system works
Our immune systems don’t work like a light switch that goes simply on or off. Think of it more like a dimmer switch. With dimmer switches, the switch can go all the way up, but it can also go somewhere in between fully bright and completely off. If you stopped the switch in the middle, it’s not off – you can still see, but it is dim.
The immune system is in many ways similar to the dimmer switch. When you are vaccinated, the switch to make antibodies in your body is slowly turned up and more and more antibodies get made. Antibodies are what give you immunity.
A vaccine with 95% efficacy means that in the clinical trials, 95% of people had full protection after getting the vaccine. This doesn’t mean that the other 5% did not get any protection. It just means that their immune system “dimmer switch” got partially there, and that without the vaccine there would have been zero protection. Their bodies made antibodies, just not enough to be considered fully protected.
However, when it comes to COVID-19, we also don’t know the number of antibodies needed to be considered fully protected. We are currently using our best estimate, based on what we know about our bodies. This is not new. We have seen this with other vaccines before, such as the MMR vaccine used to prevent measles, mumps… With the MMR vaccine, studies later revealed that when we gave everyone two doses with one month apart, almost 100% of the people were actually fully protected.
Clinical Trial Results
Clinical trials are not all the same, and cannot be compared to each other.
In the clinical trials, both mRNA vaccines were about 95 percent effective in preventing COVID-19 after the participants had received two doses. Protection, beginning 14 days after one dose of either vaccine, is greater than 90 percent. The duration of protection is not yet known for one or two doses of the vaccine but is being actively monitored. In general, some vaccines provide lifelong immunity, while others such as tetanus only work for 10 years.
In the clinical trials, the AstraZeneca COVID-19 vaccine was about 62% effective in preventing symptomatic disease starting 2 weeks after the second dose. However, AstraZeneca confirms 100% protection against severe disease, hospitalization and death in the primary analysis of their Phase III trials.
In the clinical trials, the Johnson & Johnson (Janssen) vaccine was about 66% effective in preventing moderate to severe COVID-19 and 100% effective in preventing COVID-19–related hospitalization and death after receiving one dose.
Do these clinical trial statistics mean that one vaccine is more effective than the others? No. These were not head-to-head trials, and so cannot be directly compared. There is no need to worry about the differences in either effectiveness or safety of these vaccines when your turn to be immunized comes up.
All approved vaccines in Canada provide excellent immunity against the COVID-19 extreme illness, and every vaccine gets us closer to the goal of having the novel coronavirus in control.
Check out the video Why you can’t compare Covid-19 vaccines.
Long Term Immunity
We don’t currently know how long immunity from the COVID-19 vaccines lasts, but the research is ongoing. COVID-19 vaccine trial participants continue to be monitored, so we will learn more. However, we do know that right now we can safely reduce the risks of COVID-19 disease by getting vaccinated.
The degree to which these vaccines will protect us against COVID-19 one or two years after vaccination will be determined in the future, and public health experts will recommend whether booster shots are needed as we get more information.
